JP3463231B2 - Distance measuring device and safe driving system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device and a safe traveling system. In particular, the present invention relates to a distance measuring device for measuring a distance to a detected object using a phase difference correlation method, and a safe traveling system using the distance measuring device.

[0002]

2. Description of the Related Art FIG. 1 shows a schematic configuration of a conventional distance measuring device 1 for measuring a distance to a detected object in a visual field by using a phase difference correlation method, and FIG. 2 shows an optical configuration thereof. .
This distance measuring device 1 uses photodetectors 4a and 4b such as a photo diauto (PD), and as shown in FIG. 2, a first light receiving lens 2a having an equal focal length f.
And the second light receiving lens 2b are spaced apart by a constant base line length Q (a distance between the optical axes 3a and 3b of the first and second light receiving lenses 2a and 2b). First and second photodetectors 4a and 4b are arranged at positions separated from the light receiving lenses 2a and 2b by the focal length f.

However, in the distance measuring device 1 based on the phase difference correlation method, natural light or light emitted from a light projecting element (not shown) is reflected and diffused on the surface of the object to be detected OBJ. , The reflected light r is reflected by the first light receiving lens 2
The light enters the first photodetector 4a through the first optical path passing through a, and simultaneously enters the second photodetector 4b through the second optical path passing through the second light receiving lens 2b. From the first and second photodetectors 4a and 4b to the microprocessor (C
The light intensity distribution of the received light is output to the PU) 6 as image information. Then, in the microprocessor 6, the image 5a supplied from the first photodetector 4a and the second image 5a
The shift amount D of the barycentric position of the image 5b supplied from the photodetector 4b is calculated. This shift amount D corresponds to X ₁ + X ₂ in FIG. The distance L to the detected object OBJ is
Value of shift amount of center of gravity between images 5a and 5b D = X ₁
By using + X ₂ , it is obtained by the following formula based on trigonometry. L = Q · f / D ... When these operations are executed by the microprocessor 6, the result is output as distance data via the output circuit 7, as shown in FIG.

The principle of obtaining the distance L to the detected object OBJ based on the above equation, that is, the image shift amount D will be described with reference to FIG. Now, the detected object OBJ is located at a distance L from the center plane H of the first and second light receiving lenses 2a and 2b,
When it is located at a point q from the optical axis 3b of the light receiving lens 2b of the first photodetector 4a, the first photodetector 4a has the abscissa X _{1 based} on the position corresponding to the optical axis 3a of the first light receiving lens 2a. image 5a of the detected object OBJ (gravity center position) occurs, the horizontal coordinates X ₂ of the detection object OBJ from its position at that corresponds to the optical axis 3b of the second photodetector 4b second light receiving lens 2b Assuming that the image 5b (the position of the center of gravity) is generated, as shown in FIG. 3, there is a relation as shown below. Q−q = (L / f) X ₁ q = (L / f) X ₂ If q is eliminated from these two equations and X ₁ + X ₂ = D, the above equation is obtained. Therefore, in this way, the two photodetectors 4 are
By using a and 4b, it can be seen that the distance L to the detected object OBJ can be accurately obtained from the formula even if the detected object OBJ is located at an arbitrary position within the visual field.

However, since the object to be detected OBJ has a size, the first and second photodetectors 4a, 4a,
The light receiving pattern in 4b is not a point but a light intensity distribution pattern (image). Therefore, the definition of the deviation amount D cannot be used as it is, and it is necessary to expand the definition of the deviation amount D or the method of obtaining the deviation amount D. In the distance measuring device 1 using the phase difference correlation method, the shift amount D between the images 5a and 5b is obtained as follows. First, the reference line P
Define A and PB. FIG. 4A shows the first and second light receiving lenses 2a and 2b and the first and second photodetectors 4a and 4b.
FIG. 4B shows the first and second photodetectors 4a, 4
In the images 5a and 5b supplied from b, the horizontal axis represents the abscissas XA and XB on the photodetectors 4a and 4b, and the vertical axis represents the light intensity. The reference line PA shown in FIG.
It is a vertical line indicating the position of a in the screen and corresponds to the intersection A with the optical axis 3a on the first photodetector 4a. Similarly, the reference line PB is a vertical line indicating the position of the image 5b in the screen, and corresponds to the intersection B with the optical axis 3b on the second photodetector 4b. In order to obtain the shift amount D between the image 5a supplied by the first photodetector 4a and the image 5b supplied by the second photodetector 4b, first, both images 5a, 5
b is compared and the reference line PA and the reference line PB are aligned on the screen as shown in FIG.
The image 5b of b is moved together with the reference line PB so as to best match the image 5b of the other photodetector 4a. In this way, the reference line PA when the two images 5a and 5b are best matched,
The distance between the reference lines PB is defined as the deviation amount D at this time,
The distance L to the object to be detected OBJ is calculated using the formula. Note that the time when the two images 5a and 5b best match each other is as shown in FIG.
It is defined that the area of the non-overlapping area of both images 5a and 5b is the minimum area, such as the shaded area shown in (d).

In the distance measuring device 1 using such a phase difference correlation method, the two images 5a and 5b shift in the same direction even if there is a color pattern such as a pattern on the surface of the detected object OBJ. The displacement amount D is not affected, and the distance L to the detected object OBJ can be accurately measured even in such a case. Further, since the deviation amount D can be obtained with high accuracy by the correlation calculation, the distance L can be measured with high accuracy even when the detected object OBJ is at a long distance.

[0007]

However, in the method of calculating the distance by the phase difference correlation method as described above, there are two or more objects to be detected within the field of view, and there are two or more objects on the photodetector. When the image of the detected object of is formed,
As described above, even if the distance to the detected object is obtained from the shift amount when the area of the left and right images that do not overlap is the minimum, there is a problem that it does not match the distance to any of the detected objects. .

Now, two detected objects OBJ1 and OBJ
Suppose two are at different distances. For example, in FIG. 5A, the detected object OBJ1 is located at the distance L1 and the detected object OBJ1
J2 is present at a distance L2 (<L1), and the photodetector 4
As shown in FIG. 5B, an image 8a of the detected object OBJ1 and an image 9a of the detected object OBJ2 are generated on a, and the image is detected on the photodetector 4b as shown in FIG. 5C. Image 8b of detected object OBJ1 and image 9 of detected object OBJ2
b has occurred.

At this time, the image 8a is displayed as shown in FIG.
And images 8a and 8b so as to best match
b, 9a, 9b and the reference lines PA, PB are moved, and the distance obtained from the deviation amount D1 at that time matches the distance L1 to the detected object OBJ1. Further, as shown in FIG. 6B, the respective images 8a, 8b, 9a, 9b and the reference lines PA, PB are moved so that the images 9a and 9b are most matched, and the deviation amount D2 at that time is obtained. The distance matches the distance L2 to the detected object OBJ2.

However, in reality, as shown in FIG. 6 (c), when the degree of coincidence between the entire images 8a and 9a on the photodetector 4a and the entire images 8b and 9b on the photodetector 4b is the highest. The deviation amount D is calculated, and the deviation amount D at that time is D1.
Neither D2 nor two detected objects OBJ1, O
The images 8a, 8b, 9a, 9b of the BJ2 are the photodetectors 4a,
The amount of deviation D is D depending on the position on the image 4b.
Takes any value from 1 to D2.

Therefore, in the distance measuring device using the phase difference correlation method, when there are two or more objects to be detected in the field of view, the distance data output from the distance measuring device indicates which object to be detected. Since the distance is not shown, there is a problem that the distance measurement becomes unstable and the distance is erroneously measured. Moreover, when there are two or more detected objects in the field of view, it is extremely impossible to individually detect the distance to each detected object.

The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and an object thereof is to determine the distance to a detected object even when there are a plurality of detected objects in the visual field. It is to be able to measure accurately.

[0013]

A distance measuring apparatus according to claim 1 receives light emitted from a predetermined visual field and transmits the light along first and second optical paths spatially separated from each other. Light receiving optical system and a plurality of light responsive elements, and receives the light transmitted along the first optical path of the light receiving optical system to generate a one-dimensional image.
A first light detecting means for outputting an electric signal representing the light intensity distribution of the light receiving element and a plurality of light responsive elements, and receives the light transmitted along the second optical path of the light receiving optical system , Second light detecting means for outputting an electric signal representing the light intensity distribution,
Of the light intensity distributions output by the first and second light detection means,
One of the optical detection devices is a distance measuring device including a calculating unit that obtains a deviation amount on the photoresponsive element and outputs a predetermined calculation result based on the deviation amount as a distance to a detected object. From the light intensity distribution output by the means,
Extracting means for extracting a partial image from among the output light intensity distribution of the other light detecting means, and selecting means for selecting a partial image corresponding to the light intensity distribution of the extracted partial image,
The calculation means may perform the predetermined calculation based on the deviation amount of the light intensity distribution between the partial image extracted by the extraction means and the partial image selected by the selection means. It has a feature.

According to the present invention, the partial image is extracted by the extracting means, the corresponding partial image is selected by the selecting means, and the distance from the deviation amount between the extracted partial image and the selected partial image to the object to be detected. Are seeking. Therefore, the distance to the detected object can be obtained corresponding to each partial image , and the ranging accuracy does not deteriorate even when there are a plurality of detected objects in the visual field. Further, it is possible to individually detect the distances of a plurality of detected objects.

According to a second aspect of the present invention, in the distance measuring apparatus according to the first aspect, the extracting means selects from a certain extreme point to another from the light intensity distribution output from the one light detecting means. The feature is that the part up to the extreme point of is extracted as a partial image .

In this case, the image of the portion corresponding to the edge of the detected object is grasped as a characteristic portion, and the distance of the detected object is obtained using the image.

According to a third aspect of the present invention, in the distance measuring apparatus according to the first aspect, the extracting means selects from a certain extreme point to another from the light intensity distribution output from the one light detecting means. portions, portions interval between extreme points is not less than the predetermined
The feature is that it is extracted as an image .

By not extracting a portion where the interval from the extreme point to the extreme point is less than a predetermined value, the influence of noise or the like can be removed and the ranging reliability can be improved.

The embodiment described in claim 4 is defined by claim 1
In third distance measuring device, wherein said selection means to select the output that best matches a high degree of partial images from the partial images extracted by said extraction means in the light intensity distribution of the other light detecting means Is characterized by.

[0020] The selection means, all the high partial images degree of coincidence with the extracted partial image instead of selecting, by selecting only the best match high degree of partial images, preventing erroneous distance measurement, the distance measurement precision Can be improved.

[0021]

[0022]

The embodiment described in claim 5 is a method according to claim 1
4. The distance measuring device according to 4, wherein the extracting means is a partial
When a plurality of extracting an image, said selection means, for each of a plurality of partial images the extracted, select the corresponding partial image, said computing means, the light intensity distribution of said each of the partial images It is characterized in that a deviation amount is obtained, and the predetermined calculation result performed based on the largest one of the deviation amounts is output as the distance to the detected object.

According to this embodiment, since the distance calculated based on the largest amount is output, it is possible to output the distance of the object to be detected which is the closest.
Therefore, when used for a vehicle or the like, it is possible to detect the distance to the closest object.

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

The safe traveling system according to claim 6 is a contract system.
The distance measuring device according to any one of the first to fifth aspects is provided, and the distance measuring device is mounted inside or outside the vehicle in order to measure a distance to an object existing in the surroundings.

Since this safe traveling system is equipped with the distance measuring device, it is possible to reach the target detected object (in particular, the nearest front vehicle or rear vehicle) without being disturbed by the background or other detected objects. The distance can be detected with high accuracy.

[0035]

[0036]

The embodiment according to claim 7, in driving safety system according to claim 6, based on an output of at least the distance measuring device, is likely to collide with the object which the vehicle is present around It is characterized in that it is provided with a judging device for judging whether or not it is in a dangerous state.

If a judging device for judging whether or not there is a dangerous state in which there is a possibility of colliding with an object existing in the vicinity based on the output of the distance measuring device, for example, an alarm is issued in advance. To indicate that there is a risk of collision,
A collision accident can be prevented by operating the brake.

[0039]

[0040]

[0041]

[0042]

[0043]

DETAILED DESCRIPTION OF THE INVENTION

(Basic Mode of the Present Invention) FIG. 7 is a diagram showing a configuration of a distance measuring device 11 according to an embodiment of the present invention. 12a, 12
b is the photodetector 13a for the light reflected and scattered by the detected object,
It is a lens for forming an image on the light receiving surface of 13b. Thirteen
a and 13b are photodetectors such as photodiodes,
It has a large number of pixels and outputs a signal (image signal) indicating the light intensity for each pixel. 14 is one photodetector 1
An extraction unit that extracts a portion that satisfies a predetermined condition (extraction condition) from the image generated in 3a. A selection unit 15 selects a part having a high degree of coincidence with the partial image extracted by the extraction unit 14 from the images generated by the other photodetector 13b. The meaning that the degree of coincidence between the partial image extracted by the extraction unit 14 and the partial image compared by the selection unit 15 is high will be made clear by the embodiments described later. Reference numeral 16 denotes a correlation calculation unit, which selects the partial image extracted by the extraction unit 14 and the selection unit 1.
The shift amount D of the partial image selected in 5 is obtained, and the distance to the detected object is calculated based on the shift amount D. That is, the photodetectors 13a and 13b are respectively connected to the extraction unit 1
Pixels corresponding to the partial image extracted by 4 and the selection unit 1
Only the pixels corresponding to the partial image selected by 5 output a signal to the correlation calculation unit 16, and the correlation calculation unit 16 performs the correlation calculation based on the signal to calculate the distance to the detected object. An output circuit 17 outputs the distance to the detected object obtained by the correlation calculation unit 16 as distance data.

The distance measuring device 11 can measure the distance to each of the detected objects even when there are a plurality of detected objects in the visual field. Now, FIG. 8 (a)
, The detected object OBJ1 is located at a distance L1 within the visual field.
, And the detected object OBJ2 exists at the distance L2. FIG. 8B shows an image (hereinafter referred to as a left image) generated on the photodetector 13a on the left side,
18a shows a left partial image by the detected object OBJ1,
Reference numeral 19a indicates a left partial image of the detected object OBJ2. Further, FIG. 8C shows an image generated on the right photodetector 13b (hereinafter, referred to as a right image), and 18b
Shows the right part image by the detected object OBJ1, 19b
Shows the right partial image by the detected object OBJ2.

The principle of obtaining the distances L1 and L2 between the detected objects OBJ1 and OBJ2 by the distance measuring device 11 will be described below. The extraction unit 14 extracts and selects a portion of the left image generated by the photodetector 13a that satisfies the extraction condition, for example, a left partial image 19a by the detected object OBJ2 as shown in FIG. 9A. The information is transmitted to the section 15. The selection unit 15 searches for the right image generated by the photodetector 13b, and as illustrated in FIG. 9B, a portion 19 having a high degree of coincidence with the left partial image 19a extracted by the extraction unit 14.
Select b. Then, the correlation calculation unit 16 obtains the shift amount between the extracted left partial image 19a and the selected right partial image 19b. For example, as shown in FIG. 9C, the shift amount D2 is obtained from the distance between the reference lines PA and PB when the extracted left partial image 19a and the selected right partial image 19b are best matched. Next, the correlation calculation unit 16 calculates the distance L2 of the detected object OBJ2 from the calculated shift amount D2 based on the equation.

Similarly, as shown in FIG. 10A, the extraction unit 14 extracts the left partial image 18a of the detected object OBJ1 from the left image, and the selection unit 15 extracts the left partial image 18a as shown in FIG. 10B. The corresponding right partial image 18b is selected, and then, in the correlation calculation unit 16, as shown in FIG. 10C, the reference line when the extracted left partial image 18a and the selected right partial image 18b are best matched. If the shift amount D1 is obtained from the distance between PA and PB, the distance L1 of the detected object OBJ1 can be calculated.

In the conventional phase difference correlation method, the left and right images are superposed so as to be most matched with each other, and the distance of the object to be detected is calculated from the deviation amount at that time, so that only one distance data can be output. If it is not possible and there are multiple detected objects in the field of view, the distance measurement device of the related art outputs distance data that is not the distance of any detected object,
The measurement error was large. On the other hand, in the distance measuring apparatus 11 of the present invention, a part of one image that satisfies a certain extraction condition is extracted, and a part of the other image having a high degree of coincidence with the extracted partial image is extracted. Since the correlation calculation is performed in consideration of only the selected partial image selected from among the selected partial images and the selected partial image, only the detected object characterized by the above extraction condition can be separated to obtain the distance. Moreover, the distances between the detected objects can be obtained even when there are a plurality of detected objects by sequentially extracting the portions satisfying the extraction conditions by the extraction unit 14 and executing the above processing. Therefore, even when there are a plurality of detected objects, it is possible to accurately obtain each distance data corresponding to each detected object.

Although all the distances of the detected object obtained as described above may be output as distance data, the shortest distance among the obtained distances, that is, the distance of the closest detected object. May be selected and output from the output circuit 17.

(First Embodiment) This embodiment is characterized in that an extreme value is used as an extraction condition in the extraction unit 14. 11 (a) and 11 (b) are views showing the characteristics of the distance measuring method by the distance measuring device 11 according to one embodiment of the present invention. FIG. 11 (a) shows two objects at distances L1 and L2, respectively. The left image by the detection objects OBJ1 and OBJ2 is shown, and FIG. 11B shows the right image. In this embodiment, the portion that satisfies the predetermined condition (extraction condition), which is the extraction condition in the extraction unit 14, is changed from the extreme value (maximum value, minimum value or stationary value) of the image to the adjacent extreme value (minimum value). , Local maximum or stop point). The extraction condition of this embodiment is intended to extract the edge of each detected object.

In the distance measuring device 11, the extracting unit 14 includes a left partial image 20a from the minimum value to the maximum value in the left image, a left partial image 21a from the maximum value to the minimum value,
The four partial images of the left partial image 22a from the minimum value to the maximum value and the left partial image 23a from the maximum value to the minimum value are sequentially extracted. On the other hand, the selection unit 15 corresponds to each of the left partial images 20a to 23a extracted by the extraction unit 14, the right partial image 20b from the minimum value to the maximum value, and the right partial image 21b from the maximum value to the minimum value, respectively. , The right partial image 22b from the minimum value to the maximum value, or the right partial image 23b from the maximum value to the minimum value is selected. Then, the distance of the detected object is obtained from the extracted right partial image having a high degree of coincidence with the left partial image. For example, if the extraction unit 14 extracts the left partial image 20a, the selection unit 15 divides the right image into a plurality of right partial images 20b to 23b according to the same extraction condition of the extraction unit 14, and is extracted from them. Right partial image 20b having a high degree of coincidence with the left partial image 20a
Select. In the correlation calculator 16, the left partial image extracted by the extractor 14 and the right partial image selected by the selector 15 are subjected to correlation calculation to calculate the distance of the detected object.
That is, the distance L1 of the detected object OBJ1 is obtained from the left and right partial images 20a and 20b, and the left and right partial images 21a are obtained.
And 21b, the distance L1 of the detected object OBJ1 is obtained, and from the left and right partial images 22a and 22b, the detected object O is detected.
The distance L2 of BJ2 is obtained, and the left and right partial images 23a and 23
Since the distance L2 of the detected object OBJ2 is obtained from 3b as well, the output circuit 17 eventually outputs the distance data L1 and L2.

(Second Embodiment) FIGS. 12A and 12B are views showing the features of the distance measuring method by the distance measuring device 11 according to another embodiment of the present invention. In this embodiment,
The extraction condition in the extraction unit 14 is set to the extreme value (maximum value,
A partial image of a section from a minimum value or a stationary value) to an adjacent extreme value (a minimum value, a maximum value or a stationary point),
The width of the section (hereinafter, referred to as edge width) is defined to be a predetermined value or more. That is, the extraction condition in the first embodiment is characterized in that the point where the width (edge width) of the partial image is equal to or larger than a predetermined value is weighted, and the point having a small edge width is not extracted.

For example, the distance measuring device 11 may cause a data output failure due to the influence of electrical noise or optical disturbance. For example, as shown in FIG. 12A, a noise component 24 is included in an image (light intensity distribution) generated on the photodetectors 13a and 13b due to electrical noise, optical disturbance, or the like.
May occur. Therefore, with only the processing method as in the first embodiment, as a result of performing the correlation calculation on the noise component 24, there is a possibility that the distance data that does not actually include the detected object may be output.

Therefore, in this embodiment, when the edge width W from the extreme value to the extreme value is equal to or smaller than the predetermined value, the extraction condition is set so that the partial image is not extracted by the extraction unit 14. Therefore, the extraction unit 14 from the image of FIG.
When the partial image is extracted by, partial images 25 to 31 as shown in FIG. 12B are extracted, and the influence of noise can be removed to output accurate distance data.

Here, the predetermined value that gives the limit of the edge width W can be experimentally determined. That is, the test sample having the steepest edge (for example, the boundary between the white surface and the black surface) is arranged by changing the distance (set distance) from the distance measuring device 11, and then the edge of the test sample is changed. The edge width of the obtained image is measured.
FIG. 13 shows the set distance-edge width characteristics thus obtained. Then, the minimum necessary edge width W is read from FIG. 13 according to the set distance of the detected object to be detected, and the predetermined value is set to the edge width W or a value slightly smaller than that, and The extraction unit 14 does not extract a portion having a small edge width. By setting the predetermined value in this way, the partial image with the steepest edge can be extracted by the extraction unit 14, but the spike-shaped partial image due to the influence of electrical noise or the like can be prevented from being extracted. It is possible to prevent erroneous distance measurement to a detected object.

It should be noted that, here, in the case where the image extracted by the extraction unit 14 is the partial image in the section from the extreme value to the extreme value, the image having the width less than the predetermined value is not extracted, but it will be described below. Even in the case of other extraction conditions (for example, the inclination of the partial image) such as that described above, it is possible not to extract those that are equal to or less than or equal to a predetermined value.

(Third Embodiment) In the third embodiment, the position of the partial image selected by the selecting unit 15 can be limited according to the position of the partial image extracted by the extracting unit 14. Is characterized by.

For example, the detection range of the distance measuring device 11 is set to the range shown in FIG.
14A shows the position of the partial image 32 extracted in FIG.
At the position shown in (b), the partial images selected by the selection unit 15 are limited to those existing within the allowable range shown in FIGS. 14 (a) and (b).

It is assumed that the partial image 32 is extracted at the position shown in FIG. 14 (a). The image 32 is generated at this position when the detected object OBJ exists in the direction of the optical path 35. Here, if the detected object OBJ is located at the position closest to the detection range in the direction of the optical path 35, the detected object OBJ at this position is detected by the photodetector 13b.
The partial image 33 is generated on the upper side, and the detected object OBJ at the farthest position generates the partial image 34 on the photodetector 13b.
If the allowable range is set in the range including both of the partial images 33 and 34 and the partial image outside the allowable range is not selected, only the distance of the detected object OBJ existing in the detection range can be measured. it can. Note that the allowable range is the extraction unit 1
It goes without saying that it changes depending on the position of the partial image extracted by 4.

Therefore, if the range of the partial image selected by the selecting unit 15 is limited according to the position of the partial image extracted by the extracting unit 14, an object (for example, background) outside the detection range can be removed. Therefore, the processing time can be improved and the partial image can be prevented from being cross-correlated.

(Fourth Embodiment) The fourth embodiment is characterized in that the partial image extracted by the extracting unit 14 and the partial image selected by the selecting unit 15 are weighted with a tilt condition. That is, the selection unit 15 selects a partial image having a high degree of coincidence with the partial image extracted by the extraction unit 14 according to a predetermined extraction condition as a selection candidate, and the sign of the inclination between the extracted partial image and the partial image of the selection candidate. And the partial images are selected when the signs of the inclinations are the same, and not selected when the signs of the inclinations are different. Here, the sign of the inclination of the partial image may be determined by the sign of the inclination of the line segment that connects the extreme points at both ends of the partial image, or the maximum value (or the minimum value) is at the left end of the partial image. It may be determined whether it is present or at the right end.

FIGS. 15 (a) and 15 (b) are views for specifically explaining this embodiment. For example, as shown in FIG. 15A, when one detected object OBJ2 is out of the field of view,
The right image (partial image 37) of the detected object OBJ2 generated on one photodetector 13b may be partially missing.
Therefore, the detected object O generated on the photodetector 13a
Even if the partial image 36 from the minimum point to the maximum point is extracted from the left image of BJ2 and the corresponding partial image is selected from the right image, the corresponding partial image cannot be found. Therefore, there is a risk that the selection unit 15 determines that the wrong right partial image is the corresponding partial image. In this embodiment,
Since partial images having different signs of inclination are not selected, the partial images 37 and 39 of the right partial images 37 to 39 are mismatched with the left partial image 36, and are not selected by the selection unit 15. Therefore, the risk of a false correlation in the correlation calculation unit 16 can be reduced, and the reliability of the distance measuring device 11 can be improved.

(Fifth Embodiment) The fifth embodiment is characterized in that, in order to evaluate a partial image having a high degree of coincidence, a comprehensive judgment is made using an evaluation formula in consideration of various factors. For example, when there are a plurality of partial images that are considered to correspond in the photodetector 13b to an arbitrary partial image extracted by the photodetector 13a, by using an evaluation formula that indicates the degree of coincidence between the two partial images, It is possible to judge whether or not the partial images correspond to each other, and it is possible to prevent the cross-correlation between the partial images.

Ideally, the corresponding partial images generated on the left and right photodetectors 13a and 13b have the same contrast, edge width, inclination, start point height, and end point height. Therefore, as elements used in the evaluation formula, preferably, as shown in FIG. 16, the contrast of the partial image 40 (difference in light intensity at the start point 41 and the end point 42) and the width (edge width) of the partial image 40. , The slope (= contrast / width) of the line segment connecting the start point 41 and the end point 42 in the partial image 40, the start point height and the end point height (light at the start point 41 and the end point 42 of the partial image 40). Strength)
Can be used.

If the evaluation formula is constructed by using, for example, the contrast of the partial image, the width of the partial image, and the height of the starting point of the partial image among these elements, the following evaluation formula is obtained. κ = K ₁ · | Lcon-Rcon | + K ₂ · | Lwid-Rwid | + K ₃ · | Lstr-Rstr | ... where Lcon and Rcon are the partial image extracted on the photodetector 13 a and the photodetector. 13B shows the respective contrasts of the partial images that are selection candidates on 13b. Lwid and Rwid are
The widths of the extracted partial images and the partial images that are selection candidates are shown. Lstr and Rstr represent the starting point heights of the extracted partial images and partial images that are selection candidates, respectively. K ₁ , K ₂ and K ₃ are constants.

If there are a plurality of partial images that are selection candidates for the extracted partial images, the value of the above evaluation formula is calculated for each selection candidate, and the value is below a certain value. Try to choose one.

For example, as shown in FIG. 17, when there are a plurality of detected objects OBJ1, OBJ2, OBJ3,
A plurality of partial images 43a to 48a obtained by decomposing the left and right images formed on both photodetectors 13a and 13b; 43b to
The arrangement relationship of 48b is almost the same. Therefore, the strength of the correlation can be evaluated by using an evaluation formula considering the above-mentioned factors, for example, the formula, for example, the photodetector 13
Even if there is a light reception variation in a and 13b, it is possible to select a partial image that correctly corresponds to the extracted partial image.

(Sixth Embodiment) In this embodiment, partial images having a high degree of coincidence are selected based on an evaluation expression such as an expression and the sign of the inclination of the partial images. That is, as shown in FIG. 18A, there are detected objects OBJ1 and OBJ2 having similar shapes and brightness at distances L1 and L2.
Consider a case where the left image as shown in (b) is generated and the right image as shown in FIG. 18 (c) is generated. Now, if the partial image 49 is extracted from the left image, the signs of the inclinations of the partial images 50 to 53 of the right image are searched. As a result, the partial images 51 and 53 are the extracted partial images 49.
And the remaining partial image 50,
52 is determined to have a high degree of coincidence. Next, regarding the two partial images 50 and 52 and the partial image 49 having a high degree of coincidence,
Calculate the value of each evaluation formula. If the value of the evaluation expression between the partial images 49 and 50 is κ = 2, and the value of the evaluation expression between the partial images 49 and 52 is κ = 15, the selection unit 15 determines that It is determined that the smaller value of the value κ has a stronger correlation, and the corresponding partial image 50 is selected.

As shown in FIG. 19A, in the case of the detected object OBJ having a repeating pattern such as a lattice, the information provided from the partial image 50 to the evaluation formula and the evaluation formula from the partial image 52 are used. , The value of the evaluation formula of the partial image 50 for the partial image 49 is, for example, κ = 2, and the value of the evaluation formula of the partial image 52 for the partial image 49 is also κ = 2. Match. In such a case, which partial image is the corresponding partial image cannot be determined, and an incorrect determination may be made depending on the variation in the light reception of the photodetectors 13a and 13b. In such a case, if the value of the smallest evaluation expression and the value of the second smallest evaluation expression are close to each other and the difference is less than or equal to a predetermined value, it is not possible to judge and the difference between the evaluation expressions is determined. If the partial image having the smallest value of the evaluation formula is selected only when is greater than or equal to a predetermined value, it is possible to prevent the cross-correlation of partial images.

(Seventh Embodiment) In the first embodiment,
When selecting the corresponding partial image, a partial image is extracted from the left image generated in one photodetector 13a, and is generated in the other photodetector 13b with reference to this. The divided partial image is searched from the right image, and the corresponding partial image is selected. However, for example, as shown in FIG. 20, the image (partial image 58a) of the third detected object is displayed on only one of the two photodetectors 13a and 13b, and the image of the detected object is displayed on the other. It is possible that is not displayed. In such a case, there is a problem that the wrong partial image is selected as the partial image on the photodetector 13b corresponding to the partial image extracted on the photodetector 13a.

The seventh embodiment is to solve such a problem, in which the extraction part 14 extracts the left partial image,
The right partial image corresponding to the left partial image is searched for as a selection candidate, and then the left partial image corresponding to the right partial image that becomes the selection candidate is searched, and the left partial image thus searched is originally extracted. When it matches the left partial image, it is determined that the correspondence is correct, and the selection unit 15 selects the left partial image. On the other hand, if they do not match, distance measurement is not possible, and cross correlation of partial images is prevented.

20 and 21 specifically explain this embodiment. FIG. 21 shows the photodetector 1 shown in FIG.
It is a table which shows the value of evaluation formula (kappa) between the partial images 54a-58a on 3a, and the partial images 54b-57b on the photodetector 13b. If the extraction unit 14 extracts the partial image 58a, the partial image 56b is searched as the partial image having the highest degree of matching. Then, when the partial image having the highest matching degree with the searched partial image 56b is searched again, the partial image 56a is selected. Therefore, in this case, since the original partial image 58a and the re-searched partial image 56a do not match, it is determined that the partial image corresponding to the partial image 58a does not exist on the photodetector 13b, and the distance measurement is performed. Considered impossible.

(Eighth Embodiment) In order to obtain the distance to the object to be detected by the correlation calculation, as described in the conventional example, the shift amount D when the area where the two partial images do not overlap is the minimum is obtained. Calculated from
However, for example, the left and right photodetectors 13a and 13b have different light intensity distributions due to the influence of an optical shift, and as shown in FIG. 22A, the contrast CL of the left partial image 59 and the contrast CR of the right partial image 60 are different. And the point where the non-overlapping area of the two partial images 59 and 60 is the minimum (referred to as the area minimum point) and the point where the images overlap most due to the difference in the contrast CL and CR of the left and right partial images 59 and 60. Without doing so (FIG. 22B), an incorrect distance may be calculated. To solve this,
As shown by a broken line 61 in FIG.
It is advisable to correct the light intensity distribution of the partial image 60 output from 3a or 13b so that the contrasts of both images 59 and 60 match. By doing so, it is possible to correctly detect the point where the area where the two partial images do not overlap is minimized (see FIG. 2).
2 (c)).

(Ninth Embodiment) For example, when calculating the distance of a high-brightness detected object such as a tail lamp of a vehicle, as shown in FIG. A light amount difference may occur in the outputs (left image 62, right image 63) from the photodetectors 13a and 13b. At this time, the partial image 64a extracted / selected from the images 62, 63 (or the image 62 having the same light intensity distribution as the image 63 'shown by the broken line) supplied from the two photodetectors 13a, 13b. , 64b and the distance of the detected object obtained from the partial images 65a and 65b extracted / selected from the images 62 and 63 are not equal to each other, and different distances are caused by the influence of the light amount difference. It will be calculated.

[0074] determined from thus when the luminance of the detected object is high and it has been found that the distance is equal by each partial image shift amount obtained from the partial images 64a and 64b and the partial images 65a and 6 5b Average the amount of deviation,
The distance may be obtained by using the average amount of deviation. As a result, it is possible to correct the shift of the image due to the difference in the light amount and output the correct distance.

As an effective case of averaging the deviation amounts, if the inclinations of all the partial images are equal to or more than a predetermined value, or if the absolute values of the contrasts of all the partial images are equal to or more than a predetermined value, There are cases where the partial images to be averaged are continuous and the sign of the inclination is reversed.

(Tenth Embodiment) In each of the above embodiments, only the distance to the detected object is detected.
In this embodiment, the direction of the detected object is detected together with the distance of the detected object. That is, as shown in FIG. 24, the detected object OBJ exists at the position of the distance L in the direction connecting the center of gravity of the images 66a and 66b and the centers of the lenses 12a and 12b on the photodetectors 13a and 13b. If the coordinates of the barycentric positions of the images 66a and 66b on the detectors 13a and 13b are X ₁ and X ₂ , respectively, the lens 12
The direction θ of the detected object OBJ drawn from the center of a, 12b toward the detected object OBJ is obtained from θ = (2LX ₁ −fQ) / 2fL = − (2LX ₂ −fQ) / 2fL. According to this equation, the correlation calculator 16 or the like calculates the direction θ of the detected object OBJ, and the output circuit 17 outputs the distance L and the direction θ.

(Eleventh Embodiment) Further, the distance measuring device 11 causes the distance L (and the direction θ) of the object OBJ to be detected.
At the same time, the size (size) of the detected object can be detected. If the distance L of the detected object OBJ is obtained, the size E of the detected object OBJ can be obtained from E = (L / f) e from the similarity relationship shown in FIG. Here, e is a detected object OBJ generated on either photodetector 13a or 13b.
Width of the image 66a or 66b (or both photodetectors 1
3a and 13b are the average widths of the images 66a and 66b).

(Safety Driving System) Next, a vehicle equipped with the distance measuring device of the present invention will be described. In a distance measuring device used for a vehicle, it is necessary to detect the closest object to be detected (the preceding vehicle in front, an obstacle, etc.), so when there are multiple objects to be detected within the visual field range, , Is set to detect and output the distance to the closest detected object. The mounting location of the distance measuring device is not particularly limited, and it can be mounted at any location according to the application. For example, it may be mounted inside the vehicle such as on the back of the rearview mirror or on the dashboard, or outside the vehicle such as a bumper or front grille on the front of the vehicle. In addition, there is no problem even if it is installed so as to monitor the rear of the vehicle or the side of the vehicle.

26 and 27 are a side view and an interior view showing an embodiment of such a vehicle 81, in which a distance measuring device 83 is attached to the rear surface of the room mirror 82.
A distance display device 85 is attached near the vehicle speed display meter 84. Then, the distance measuring device 83 is used to detect a detected object in the field of view in front of the vehicle 81 (for example, the front vehicle 86
The distance to the object to be detected in front is displayed in real time on the distance display device 85 to notify the driver of the distance to the object to be detected. Therefore, the driver can reliably drive while keeping a safe inter-vehicle distance without relying on the feeling, and it is possible to prevent an accident due to an excessively short inter-vehicle distance due to an illusion or driving fatigue.

When the conventional distance measuring device using the phase difference correlation method is used, there is a risk of calculating the distance to a distant object to be detected (for example, a vehicle ahead in one vehicle) or the background. In the distance measuring device according to the present invention, the distance to the closest detected object can be reliably calculated,
Not only can it be used as an inter-vehicle distance display system that detects the inter-vehicle distance to a vehicle in front, but it can also be safely used in a rear-end collision prevention system, a visual field assistance system, and the like as described below.

FIG. 28 is a side view showing a vehicle 81 equipped with a rear-end collision prevention system 87 using the distance measuring device 83 according to the present invention. The distance measuring device 83 of the present invention is attached to the back side of the room mirror 82 in the vehicle interior,
The field of view is set above the ground in front of the vehicle 81. Further, a warning device 90 such as a buzzer or an alarm is provided in the driver's seat. The rear-end collision prevention system 87 is configured as shown in FIG. 29, and includes information indicating the inter-vehicle distance to the forward vehicle 86 detected by the distance measuring device 83 and the vehicle in operation detected by the speed sensor 88. The information indicating the speed of the vehicle (vehicle speed) is input to the rear-end collision prevention control unit 89, and the rear-end collision prevention control unit 89 determines the degree of danger based on the inter-vehicle distance to the preceding vehicle 86 and the own vehicle speed. Then, the alarm device 90 is turned on or the brake device 91 is activated to brake the vehicle 81.

FIG. 30 shows a method of determining the degree of danger by the rear-end collision prevention control unit 89. The horizontal axis indicates the vehicle speed monitored by the speed sensor 88, and the vertical axis indicates the distance measuring device 83. It is the inter-vehicle distance from the vehicle ahead. In FIG. 30, C ₁ is a permissible area, C ₂ is a low-risk area, C ₃ is a high-risk area, and the boundaries of these areas are defined as a function of the vehicle speed and the inter-vehicle distance. Although the rear-end collision prevention system 87 does not operate in the permissible area C ₁ ,
When the vehicle enters the low-risk area C ₂ , the alarm device 90 first turns on to alert the driver by a buzzer or an alarm, and when the vehicle enters the high-risk area C ₃ , the brake device 91 automatically operates. , The vehicle 81 is forcibly decelerated or suddenly stopped. Therefore, it is possible to prevent a rear-end collision accident due to the driver's carelessness or falling asleep.

FIG. 31 is a diagram showing an operation flow of the rear-end collision prevention system 87. When the distance measuring device 83 calculates the inter-vehicle distance to the preceding vehicle 86 (S101),
The rear-end collision prevention control unit 89 controls the inter-vehicle distance and the speed sensor 88.
The degree of danger is determined from the own vehicle speed monitored by (S102), and it is determined in which area in FIG. 30 the vehicle is located. Then, it is judged whether or not it is within the allowable region C ₁ (S
103), if it remains within the permissible area C ₁ , the risk level is continuously monitored (S101 to S103). If it is not within the allowable area C ₁ , it is judged whether it is the low-risk area C ₂ or the high-risk area C ₃ (S104), and if it is the low-risk area C ₂ , the alarm device 90 is activated (S105), Danger area C ₃
If so, the brake device 91 is operated (S106).

In the rear-end collision prevention system 87, the danger area is divided into the warning operation area and the brake operation area, but the brake operation area is further divided into two areas. May be forcibly decelerated and the vehicle may be stopped suddenly by applying a sudden brake when the brake operating range becomes higher.

FIG. 32 is a plan view showing a vehicle 81 equipped with a visual field assistance system 92 using the distance measuring device 83 according to the present invention. The distance measuring device 83 according to the present invention includes, for example, left and right side mirrors 93 and a bumper 94 on the rear surface of the vehicle.
Are attached to both left and right sides of the vehicle, and the fields of view (areas hatched in FIG. 32) are set to the vehicle rear side and the vehicle side portion rear side. The visual field assistance system 92 provides visual field assistance when changing lanes and visual field assistance during back parking. An alarm device 95 (or display device) is provided in the driver's seat. As shown in FIG. 33, the information indicating the distance to the detected object behind detected by the distance measuring device 83, the information indicating the own vehicle speed detected by the speed sensor 88, and the back lamp control signal 97. And a turn signal control signal 98 are input to the visibility assistance control unit 96. The visibility assistance control unit 96 determines the degree of danger at the time of changing lanes or at the time of back parking. Turn on and warn the driver.

FIG. 34 is a diagram showing an operation flow of the visibility assisting system 92 when changing lanes. When changing lanes, the turn signal on the turn side blinks for changing lanes, but when the control signal for the right or left turn signal is transmitted (S107), the visibility assist control unit 96 causes the turn signal control signal 98 to be displayed. Is detected, the distance measuring device 83 and the speed sensor 88 on the moving side are operated (S108), and a signal indicating the distance from the distance measuring device 83 to the following vehicle on the rear side is sent to the visibility assist control unit 96. A signal indicating the vehicle speed is output from the speed sensor 88 to the visibility assist control unit 96.
Is output to. The visibility assist control unit 96 determines the state of the vehicle 81 from these signals and determines the risk of lane change (the risk is a function of the distance to the detected object and the vehicle speed) (S109). , S110). As a result, when it is determined that the information is dangerous, the alarm device 95 is sounded (or displayed on the display device) to warn (S111). Therefore, when the warning is given, the driver can stand by without changing the lane until the warning is released, thereby preventing an accident due to the lane change.

Further, FIG. 35 shows the visibility assisting system 92.
It is a figure which shows the operation | movement flow at the time of back parking. When backing up, the back lamp blinks, but when this back lamp control signal is transmitted (S112), the visibility assist control unit 96 detects the back lamp control signal 97, and the back distance measuring device 83 Activate the speed sensor 88 (S1
13), the distance measuring device 83 outputs a signal indicating the distance to the object to be detected (parked vehicle, wall, child, etc.) to the visibility assist control unit 96, and the speed sensor 88 indicates the vehicle speed. The signal is output to the visual field assistance control unit 96. The visibility assistance control unit 96 determines the state of the vehicle 81 from these signals and determines the risk of back parking (S114, S115). As a result, when it is determined that the information is dangerous, the alarm device 95 is sounded (or displayed on the display device) to warn (S116). Therefore, when the warning is given, the driver can immediately apply the brakes to stop, and it is possible to prevent a collision accident or a contact accident with an obstacle or a child. In this case, an alarm may be sounded even outside the vehicle to warn a child or the like behind the vehicle.

FIG. 36 is a block diagram showing an automatic follow-up control system 121 using the distance measuring device 83 according to the present invention, which is for semi-automatic follow-up of the front vehicle 86 while keeping a substantially constant inter-vehicle distance. It is a device. Also in this case, the distance measuring device 83 of the present invention is attached, for example, behind the room mirror 82, and the field of view is set forward (FIG. 26). The information indicating the inter-vehicle distance to the forward vehicle 86 detected by the distance measuring device 83 and the information indicating the own vehicle speed detected by the speed sensor 88 are input to the automatic tracking control unit 122, The automatic follow-up control unit 122 controls the accelerator control device 123 and the brake control device 12 according to the inter-vehicle distance and the vehicle speed.
You are controlling 4.

FIG. 37 is a diagram showing a determination method by the automatic tracking control unit 122. The curve E is an ideal curve of the inter-vehicle distance to the preceding vehicle 86 and the vehicle speed when the vehicle runs semi-automatically, and the area F ₁ including the curve E has an inter-vehicle distance that is wider than the ideal inter-vehicle distance or an ideal inter-vehicle distance. It is an ideal area that is allowed even if it is overly clogged. In addition, this ideal region F ₁
Out of the areas outside, the area F ₂ is an area where the inter-vehicle distance is too wide and needs to be adjusted, and the area F ₃ is an area where the inter-vehicle distance L is too narrow and needs to be adjusted. The automatic tracking control unit 122 determines from which output signal of the distance measuring device 83 and the speed sensor 88 the vehicle state is in FIG. 37, and when the vehicle state is in the ideal area F ₁ , the driving of the vehicle 81 is performed. However, when the state of the vehicle 81 deviates from the ideal region F ₁ , the accelerator control device 123 and the brake control device 124 are controlled according to the flow chart of FIG. 38.
Keep track of a safe and optimal vehicle distance.

The control operation of the automatic tracking control system 121 will be described with reference to the flowchart of FIG. The inter-vehicle distance to the front vehicle 86 is calculated by the distance measuring device 83 (S131), and the automatic tracking control unit 122 determines the state of the vehicle 81 from the inter-vehicle distance and the own vehicle speed, and the state of the vehicle 81 and the ideal state. And are compared (S132). As a result, the vehicle 8
When it is determined that the state of 1 is in the ideal area F ₁ , (S
133), the driving is left to the driver without outputting the control signal to the brake control device 124 or the accelerator control device 123, and the comparison between the vehicle state and the ideal state is repeated (S131 to S133). On the other hand, the ideal area F
If it is determined that the _first outer further whether the region F _2, to determine whether the region F ₃ (S134), when it is determined that the area F ₂ of the past away following distance, A control signal is output to the accelerator control device 123, the accelerator opening is increased, and the distance L with the preceding vehicle 86 is reduced (S13).
5). On the other hand, when it is determined that the inter-vehicle distance is in the region C ₃ where the inter-vehicle distance is too close, a control signal is output to the accelerator control device 123 or the brake control device 124 to reduce the accelerator opening or activate the brake. To maintain a sufficient inter-vehicle distance (S136).

FIG. 39 is a block diagram showing a system 125 for supporting driving of a vehicle during traffic congestion. During a traffic jam, it is not possible to predict when the forward vehicle 86 will move forward. Therefore, the driver constantly pays attention to the forward vehicle 86 and immediately after the forward vehicle 86 moves, the vehicle 81
Have to move forward to reduce the distance between cars. For this reason, driving during a traffic jam is tired and irritable. This system is intended to facilitate driving during such traffic congestion. This vehicle 8
1, the distance measuring device 83 of the present invention is attached, for example, to the rear of the room mirror 82, and the field of view is set forward (FIG. 26). The information indicating the inter-vehicle distance to the front vehicle 86 detected by the distance measuring device 83 and the information indicating the own vehicle speed detected by the speed sensor 88 are input to the front vehicle start detection control unit 126. Therefore, the forward vehicle start detection control unit 126 activates the alarm device 127 (or display device) to notify the driver when the inter-vehicle distance is a certain value or more. That is, as shown in FIG. 40, the forward vehicle start detection control unit 126 determines whether or not the own vehicle speed is 0 based on the signal from the speed sensor 88 (S141), and when the own vehicle speed is 0, the vehicle is stopped due to traffic congestion. It is determined that it is in the middle, and the following processing for traffic congestion is executed. The front vehicle start detection control unit 126 monitors the inter-vehicle distance to the front vehicle 86 calculated by the distance measuring device 83 (S142), and the inter-vehicle distance is a fixed value determined in consideration of an appropriate inter-vehicle distance during traffic congestion. It is determined whether the value is equal to or more than the value (S143). Then, when the front vehicle 86 moves forward and the inter-vehicle distance deviates by a certain value or more, the alarm device 12
7 is operated (S144), and the driver is urged to reduce the inter-vehicle distance. By using such a system 125, the driver is relieved of the burden of constantly paying attention to the movement of the forward vehicle 86, and the driver is nervous, for example, during a traffic jam.
Can be softened and have a lot of room.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a conventional distance measuring device that measures a distance by a phase difference correlation method.

FIG. 2 is a diagram showing an optical configuration of the above.

FIG. 3 is a diagram illustrating a principle for measuring a distance to a detected object in the above distance measuring device.

4 (a), (b), (c), and (d) are diagrams for explaining a method of obtaining a deviation amount in the above distance measuring device.

5A is a diagram showing a state in which two detected objects are present in the field of view, and FIGS. 5B and 5C are diagrams showing images of light intensity supplied from a photodetector in this case. .

6 (a), (b), and (c) are diagrams showing how the image shift amount is obtained by different methods in the situation as shown in FIG.

FIG. 7 is a diagram showing a configuration of a distance measuring device according to an embodiment of the present invention.

8A is a diagram showing a state in which a plurality of detected objects are present in the visual field of the above distance measuring device, and FIGS. 8B and 8C are diagrams showing a left image and a right image at that time. .

FIG. 9A is a diagram showing an extracted partial image, and FIG.
Is a diagram showing a selected partial image, and FIG. 7C is a diagram showing a state in which both images are matched to obtain a shift amount.

FIG. 10A is a diagram showing another extracted partial image;
(B) is a figure which shows another selected partial image, (c) is a figure which shows a mode that both images are made to correspond and the deviation | shift amount is calculated | required.

11A and 11B are views showing left and right images,
The feature of another embodiment of this invention is demonstrated.

FIG. 12 is a diagram showing the characteristics of still another embodiment of the present invention, in which (a) is a diagram showing an image output from a photodetector and (b) is a partial image extracted from the image. FIG.

FIG. 13 is a diagram showing a set distance-edge width characteristic of the distance measuring device.

14 (a) and 14 (b) are views for explaining the characteristics of still another embodiment of the present invention.

15 (a) and 15 (b) are views for explaining the characteristics of still another embodiment of the present invention.

FIG. 16 is a diagram illustrating an evaluation element of a partial image according to still another embodiment of the present invention.

17 (a) and 17 (b) are diagrams for specifically explaining the embodiment of the above.

18 (a), (b) and (c) are views for explaining the characteristics of still another embodiment of the present invention.

19 (a), (b) and (c) are views for explaining different situations of the above-mentioned embodiment.

FIG. 20 is a diagram for explaining the characteristics of yet another embodiment of the present invention, showing a state in which there is a detected object in which an image is generated only in one photodetector.

FIG. 21 is a diagram showing a table of values of evaluation formulas in the above case.

22 (a), (b) and (c) are views for explaining the characteristics of still another embodiment of the present invention.

FIG. 23 is a diagram for explaining the characteristics of still another embodiment of the present invention.

FIG. 24 is a diagram for explaining the characteristics of still another embodiment of the present invention.

FIG. 25 is a diagram for explaining the characteristics of yet another embodiment of the present invention.

FIG. 26 is a side view showing a vehicle according to the present invention.

FIG. 27 is a partially cutaway schematic view showing the interior of the above vehicle.

FIG. 28 is a side view showing a vehicle equipped with the collision prevention system of the present invention.

FIG. 29 is a block diagram showing the collision prevention system of the above.

FIG. 30 is a diagram for explaining a method of determining the degree of danger in the collision prevention control unit.

FIG. 31 is a flowchart showing a processing procedure in the above collision prevention system.

FIG. 32 is a plan view showing a vehicle equipped with the visual field assistance system of the present invention.

FIG. 33 is a block diagram showing the visibility assistance system of the above.

FIG. 34 is a flowchart showing a processing procedure when changing lanes in the visual field assistance system.

FIG. 35 is a flowchart showing a processing procedure at the time of back parking in the visual field assistance system.

FIG. 36 is a block diagram showing an automatic tracking system of the present invention.

FIG. 37 is a diagram showing an ideal region of a vehicle state in the above automatic tracking.

FIG. 38 is a flowchart showing a processing procedure in the above-described automatic tracking system.

FIG. 39 is a block diagram showing a system for facilitating driving during traffic congestion of the present invention.

FIG. 40 is a flowchart showing a processing procedure in the above system.

[Explanation of symbols]

11 Distance measuring device 12a, 12b lens 13a, 13b photodetector 14 Extractor 15 Selector 16 Correlation calculator 17 Output circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Takagi 10 Ouron Co., Ltd., Hanazono Todo-cho, Ukyo-ku, Kyoto City, Kyoto Prefecture (56) References JP-A-7-306038 (JP, A) JP-A-5- 265547 (JP, A) JP-A-3-246412 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01B 11/00-11/30 G01C 3/00-3/32

Claims (7)

(57) [Claims] 1. A light receiving optical system for receiving light emitted from a predetermined visual field and transmitting the light along first and second optical paths spatially separated from each other, and a plurality of photoresponsive elements, A first light detecting means for receiving light transmitted along a first optical path of the light receiving optical system and outputting an electric signal representing a one-dimensional light intensity distribution; and a plurality of light responsive elements, Second light detecting means for receiving the light transmitted along the second optical path of the light receiving optical system and outputting an electric signal representing a one-dimensional light intensity distribution; and outputs of the first and second light detecting means. Of the light intensity distribution
A distance measuring device comprising: a calculating unit that obtains a shift amount on the photoresponsive element, and outputs a predetermined calculation result performed based on the shift amount as a distance to a detected object. Part of the light intensity distribution output by the means
Comprising extracting means for extracting an image from among the output light intensity distribution of the other light detecting means, and selecting means for selecting a partial image corresponding to the light intensity distribution of the extracted partial image, and the operation The means is a partial image extracted by the extraction means.
Distance measuring apparatus characterized by performing a predetermined operation based on the shift amount of the light intensity distribution of the selected partial images by the image and the selecting means. 2. The distance measuring device according to claim 1, wherein the extraction means is a portion from a certain extreme point to another extreme point in the light intensity distribution output from the one light detecting means. Is extracted as a partial image . 3. The distance measuring device according to claim 1, wherein the extraction unit is a gap from a certain extreme point to another extreme point in the light intensity distribution output from the one light detecting unit. A distance measuring device characterized by extracting a portion of a predetermined number or more as a partial image . 4. The distance measuring device according to claim 1, wherein the selecting means selects the partial image extracted by the extracting means from among the light intensity distributions output from the other light detecting means. A distance measuring device characterized by selecting a partial image having a high degree of coincidence. In the distance measuring apparatus according to claim 5] claims 1-4, wherein when the extracting means is a plurality of extracting a partial image, said selection means, for each of a plurality of partial images the extracted, corresponding Selecting the partial image to be processed , the calculating means obtains the deviation amount of the light intensity distribution for each of the partial images , and receives the predetermined calculation result based on the largest one of the deviation amounts. A distance measuring device characterized by outputting as a distance to a detected object. 6. A safe traveling comprising the distance measuring device according to any one of claims 1 to 5, wherein the distance measuring device is mounted inside or outside a vehicle in order to measure a distance to an object existing in the surroundings. system. 7. The safe traveling system according to claim 6, wherein at least based on the output of the distance measuring device,
A safe traveling system characterized by comprising a judging device for judging whether or not the own vehicle is in a dangerous state in which there is a possibility of colliding with an object existing around.