JP4036503B2 - Ranging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a distance measuring device used for a camera or the like, and more specifically, a so-called passive type that detects a luminance distribution of a subject with a predetermined parallax and measures a distance to the subject according to a plurality of obtained image signals. The present invention relates to a distance measuring device.
[0002]
[Prior art]
In order to obtain an image signal of a subject, a sensor array in which light receiving elements are arranged in an array is generally used. However, a circuit that processes the output of the sensor array has a predetermined dynamic range and is extremely bright. And an accurate image signal cannot be obtained simultaneously from both extremely dark objects.
US Patent 4410 2 Japanese Laid-Open Patent Application No. 61 and Japanese Patent Laid-Open No. 5-264887 disclose a technique for obtaining an accurate image signal regardless of the brightness of the subject.
[0003]
[Problems to be solved by the invention]
However, in these conventional techniques, a contrast image signal cannot be obtained in a backlight scene with a bright background and a dark subject, and the result of distance measurement may be inaccurate.
[0004]
For example, U.S. Pat. 2 In 61, the integration amount of the output current of the sensor array reached a predetermined level. sometimes Integration is terminated, but in this case, if the output of the sensor that receives light from the background with a bright background is increased, the integration is terminated even if the integration result of the subject has not yet reached an appropriate level. . Therefore, the image signal used for distance measurement does not have sufficient contrast.
[0005]
In order to solve such a problem, Japanese Patent Application Laid-Open No. 5-264887 calculates by extending the integration time when detecting backlight. However, if the integration time is simply increased, there is a problem that the time lag becomes longer or extra calculation is required and the control method becomes complicated.
[0006]
The distance measuring device of the present invention has been made paying attention to such a problem, and the object of the distance measuring device is to provide a high-speed and accurate distance measurement with a simple configuration that can obtain the contrast of a subject even in backlight. An object of the present invention is to provide a distance measuring apparatus capable of performing the above.
[0007]
Also, another object of the present invention is to correctly correct even when the luminance distribution of the subject is large and the correct image signal cannot be obtained beyond the dynamic range of the circuit regardless of whether it is a backlight scene or not. An object of the present invention is to provide a highly accurate distance measuring device capable of measuring a distance.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a distance measuring device according to a first aspect of the present invention provides a plurality of pairs of sensor arrays for detecting luminance distributions of subjects existing in a plurality of areas in a screen as image signals. And above Amplifying and integrating means for amplifying and integrating the output signals of a plurality of pairs of sensor arrays, and switching the sensitivity characteristics of the amplification or integration to at least two stages Integral amplification Switching means; The image signal state detection means that switches the output of the amplification integration means for each of the plurality of pairs of sensor arrays and the image signal state detection means that can detect the integration state by the output of the amplification integration means for each of the plurality of pairs of sensor arrays. Switching means for outputting to the means; In the distance measuring apparatus comprising calculation control means for calculating information related to the distance to the subject in accordance with image signal positions based on the output of the plurality of pairs of sensor arrays, the calculation control means is controlled by the amplification integration means. The result of detecting the output signal of the plurality of pairs of sensor arrays obtained by switching and amplifying and integrating the amplification or sensitivity characteristics so that the amplification factor or sensitivity is lower, and detecting the image signal state detecting means by switching the switching means The image signal state detection means detects the output of the amplification integration means of the sensor array of the output signal showing the lowest luminance after the sensor array of the output signal showing the lowest luminance is selected and selected based on The switching means is set as described above, and the amplification or sensitivity characteristic is switched by the integral amplification switching means so that the amplification factor or sensitivity is higher, and the selected sensor is selected for the same subject by the amplification integration means. Image signals with different amplification or sensitivity characteristics of the same subject obtained for the selected sensor array by amplifying and integrating the output signal of the array , The data is synthesized by removing the invalid data, and information on the subject distance is obtained based on the synthesized image signal.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, a first embodiment of the present invention will be described. FIG. 1 is a diagram showing the configuration of the first embodiment of the present invention. In FIG. 1, reference numerals 1a and 1b denote a pair of light receiving lenses that receive light from the scene 8 and guide it to the sensor arrays 2a and 2b. Each sensor constituting the sensor arrays 2a and 2b is incident with a light beam whose intensity is determined according to the luminance distribution of the subject 9, and outputs a photocurrent depending on the amount of incident light. The amplifier (AMP) 3 amplifies and integrates these photocurrents. As the AMP3, a type that amplifies the integrated voltage may be used. However, the amplification factor at this time can be switched by the switching means 5. Specifically, the photocurrent is amplified by current, the capacitance of the integration capacitor is switched, or the voltage after integration is amplified by voltage. You may make it do.
[0012]
FIG. 2A shows an integrated waveform when light from a high-luminance subject portion is received, and FIG. 2B shows an integrated waveform when light from a low-luminance subject portion is received. .
[0013]
Since FIG. 2A is a case of high luminance, the photocurrent of the sensor output is large, and the time for the integrated voltage to reach an appropriate level can be shorter than in the case of the low luminance of FIG.
Here, the appropriate level is a voltage determined by the resolution of the A / D conversion of the reading means 4 for reading the integration result and the dynamic range of the AMP3. For example, if the power supply voltage is an amplifier of 3V, amplification of 3V or more cannot be performed, and the appropriate level is 3V or less. When the resolution of the reading means 4 is 10 mV and the A / D converter is 8 bits, an integral voltage of 255 × 10 mV = 2.55 V or more cannot be read, and the appropriate level is 2 .55V.
[0014]
The integrated voltages shown in FIGS. 2A and 2B also change depending on the above-described gain switching state. As shown in the figure, t _INT In the integration time of FIG. 2A, when the luminance is high in FIG. 2A, the lower amplification factor is at an appropriate level. Therefore, the case where this amplification factor is set is referred to as a low sensitivity mode, and FIG. When the luminance is low, the higher amplification factor is an appropriate level, and this case is called a high sensitivity mode.
[0015]
That is, a bright subject image can be A / D converted at an appropriate level in the low sensitivity mode, and a dark subject image can be A / D converted at an appropriate level in the high sensitivity mode. Therefore, in the scene 8 as shown in FIG. 1, since the background of the subject 9 is bright, the background is appropriate in the low sensitivity mode as shown in FIG. 3A, and in the high sensitivity mode as shown in FIG. 3B. In addition, a person becomes a proper image. Of course, the result is opposite in the case of front light.
[0016]
Returning to FIG. 1, the comparison means (COMP) 6 for integral control is a circuit that monitors the maximum value and average value of the outputs of all sensors in real time. Further, the reading unit 4 reads an image signal output from each sensor and inputs it to the CPU 10.
[0017]
The CPU 10 is an arithmetic control circuit composed of a one-chip microcomputer or the like, and controls the integration while monitoring the relationship between the integration voltage and the integration time by the outputs of the built-in timer 7 and COMP 6. Further, the CPU 10 calculates the distance L to the subject 9 according to the shift amount x of the image positions on the two sensor arrays 2a and 2b input by the reading unit 4.
[0018]
If the distance between the principal points of the two light receiving lenses is the base line length B, and the distance between the light receiving lens and the sensor array is f,
L = (B · f) / x
The relationship is established.
[0019]
In the distance measuring apparatus having such a configuration, if the COMP 6 is a maximum value detection type, when the output reaches the above-described appropriate level, the CPU 10 outputs an integration end signal and the reading means 4 outputs each signal. If the sensor data is read, an image signal as shown in FIG. However, since the image of the subject 9 is important in the scene of FIG. 1, the subject 9 cannot be accurately measured in the state of FIG. Even if the COMP 6 is an average value detection type, if the face of the person as the subject 9 is shadowed and has a low luminance, it is difficult to accurately capture the person image.
[0020]
As shown in FIG. 2, in order to capture the shadow image of a person's face more accurately, as shown in FIG. 2, there is a method of obtaining a proper level of integration voltage by extending the integration time, and a method of switching sensitivity even at the same integration time. There is. In the present embodiment, the sensitivity switching is adopted, and the integration control is intended to be performed in a shorter time.
[0021]
FIG. 4 is a flowchart showing details of the integral control according to the first embodiment of the present invention.
First, S1 is a step of controlling the AMP3 to set a low sensitivity prior to the start of integration. The step S2 starts the integration, and S3 determines whether or not the integration voltage has reached a predetermined level according to the output of the COMP6. It is a step to do. S4 is a step of measuring the integration time and storing it as t1. If it is determined in step S3 that the predetermined level has been reached, the integration is terminated in step S5. S6 is a step of reading out the output of the sensor array subjected to integration control in this way by the reading means 4 and inputting it to the CPU 10.
[0022]
Next, in step S7, if the shape of the image signal as shown in FIG. 3 based on the sensor data is determined, it can be determined whether or not the backlight is in the backlit state. If it is not backlit, the face of the person is not shadowed and an accurate image signal should be obtained. Therefore, the process branches to step S14 to detect the amount of deviation between the two images described before the sensor data. Calculate the distance.
[0023]
However, if a backlight condition is detected in step S7, such as when the brightness at the center is significantly lower than the brightness at the periphery, the process proceeds to step S8, the high sensitivity mode is set, and integration is started (step S9). . At this time, if the integration control using the output of COMP6 as in steps S3 and S4 is performed, the integration ends at a bright place in the vicinity as before, and a person image cannot be obtained. Therefore, here, the control method is changed, and the integration is repeated for the period of t1 previously obtained in step S4 to complete the integration (steps S10, S11, S12). At this time, the output of the previous COMP 6 is ignored.
[0024]
In such a state, when the sensor data is read out in the next step S13, the integration time is the same as in the case of the low sensitivity, but the bright background data is saturated and the dark person's data is saturated as the sensitivity is increased. The data is appropriate as shown in FIG. This sensitivity difference is gained and set from 8 times to 16 times. However, the gain may be calculated from the slope of the change in the sensor data read out in step S6, and switching may be performed according to the value. Good.
[0025]
As described above, in the present embodiment, when it is determined that the light is backlit, the integral control method that monitors the integration level is switched to the integral control method that switches the sensitivity while keeping the integration time constant. This enables more accurate distance measurement in a backlight scene. Further, in the method of extending the integration time, in order to secure an integration amount equivalent to 8 times the gain, 8 times of integration time is required, and the time required for ranging becomes longer. According to such a sensitivity switching method, there is no time lag and higher-speed ranging is possible.
[0026]
The second embodiment of the present invention will be described below. In the second embodiment, as shown in FIGS. 3A and 3B, in order to effectively use both sensor data acquired by switching the sensitivity, two obtained waveforms are combined and It is used for ranging as one waveform.
[0027]
FIG. 5 is a conceptual diagram for explaining a second embodiment of the present invention. The waveform in FIG. 5A is the low sensitivity mode, and the sensor data is 0 in the section from S1 to S2 because the subject is too dark. On the other hand, the waveform in FIG. 5B is in the high sensitivity mode under the same conditions, and the data in the section from S1 to S2 is 0 or more, but it is related to the dynamic range of the circuit and the range of A / D conversion. , S1 and below, S2 and above are saturated. In the case of 8-bit A / D conversion, the value is fixed to 255. Therefore, if a predetermined offset value OFF is added to the data of FIG. 5A and then combined with the data shown in FIG. 5B, a new waveform as shown in FIG. 5C is obtained. Thus, sensor data corresponding to a dark place to a bright place can be obtained. When the image signals in FIGS. 5A and 5B are 8 bits, the data is 16 bits. However, the CPU 10 may divide the data by 2 and handle it as 8 bits data.
[0028]
The second embodiment described above is particularly useful when the change in brightness of the subject is too large and does not fall within the dynamic range of one integration. Accurate distance measurement cannot be performed in an area where there is no data such as between S1 and S2 in FIG. 5A, and accurate distance measurement cannot be performed even if a part of the image used for distance measurement is zero or saturated. . Therefore, as in the present embodiment, it is possible to perform more accurate distance measurement by measuring the distance in a form supplemented with these zero data and saturation data.
[0029]
FIG. 6A is a flowchart showing details of the integral control according to the second embodiment of the present invention.
Steps S20 to S23 are steps of integration and sensor data reading when low sensitivity is set. Subsequent steps S24 to S27 are steps of integration and reading of sensor data in the high sensitivity mode. The image signals obtained in the above steps S23 and S27 correspond to the image signals shown in FIGS. 5 (a) and 5 (b).
[0030]
Step S28 is a step of detecting areas S1 and S2 in which the sensor data in FIG. 5A is 0, and step S29 is an offset value OFF shown in FIG. The sensor data is added to a portion other than 0 and stored in the RAM of the CPU 10, and the sensor data between S1 and S2 in FIG. 5B is stored in the RAM in step S30.
[0031]
In this case, the memory (RAM) in the CPU 10 has, for example, a sensor No. Sensor data is stored in a storage area corresponding to 1 to 255 in the order shown in FIG. That is, data obtained by adding the offset value OFF to the data in FIG. 5A is stored in the addresses up to S1 in the RAM, and the data in FIG. 5A is also stored in the addresses from S2 to 255 at the same time. Input data with offset value OFF added. Further, the corresponding data in FIG. 5B is input between the RAM addresses S1 and S2. Then, the image signal of FIG. 5C is obtained by graphing the data on the RAM. Although only one data of the sensor array of FIG. 1 has been described here, the same processing is performed for the other sensor array. If the image shift amount is calculated using the data string on the RAM arranged at each address in this way, the CPU 10 can obtain the distance of the subject (S31).
[0032]
As described above, according to the present embodiment, for each of the sensor arrays, after selecting and combining the good image signal portions obtained by the integration results twice, combining the image signals, Since detection is performed, accurate ranging is possible even for a subject whose luminance changes beyond the dynamic range of the circuit.
[0033]
The third embodiment of the present invention will be described below. In the third embodiment, the distance measuring device of the above-described embodiment is applied to a camera having a so-called multi-AF (multi-point distance measuring) function.
[0034]
FIG. 7A shows a scene in which the main subject does not exist in the center of the screen. In this case, in the case of a camera that can measure the distance only in the center of the screen, the landscape is in focus, and the people on both sides It becomes out of focus. Therefore, a long sensor array with a large number of sensors is used so that a plurality of points in the screen can be measured, and the distance measuring points can be switched depending on which part of the obtained image signal is used. This configuration will be described later with reference to FIG.
[0035]
Such a camera with a multi-function often shoots without placing the subject in the distance measurement target mark in the viewfinder, and it is not necessarily the case that an appropriate signal is included in the previous distance image signal part. Not exclusively. For example, in the distance measurement area L on the left side of the screen in FIG. 7A, the person 9a is partly behind the tree and changes greatly in brightness, and part of the distance measurement area L includes the background. It has been. Sensor data in this case is shown in FIGS. 7B and 7C. FIG. 7B shows a case where integration control by the low sensitivity mode is adopted, and FIG. 7C shows a case where integration control by the high sensitivity mode is adopted. However, there is no data in the portion I in the area L in FIG. 7B corresponding to the distance measuring area L in FIG. 7A, and the figure corresponds to the distance measuring area L in FIG. The portion J in the area L of 7 (c) is saturated and is not appropriate data.
[0036]
Therefore, by storing such missing data in such a manner that the camera built-in CPU supplements each image data by combining them, synthesized data as shown in FIG. 6B is obtained on the memory.
[0037]
On the CPU RAM obtained in this way, the sensor No. If the data arranged according to is graphed, it becomes as shown in FIG. 7D, and there is no inappropriate data that is 0 or saturated in the area L, and accurate distance measurement is possible. .
[0038]
As described above, when the L, C, and R points are measured using the composite image signal suitable for distance measurement and the point indicating the closest distance is focused, the persons 9a and 9b are detected. You can shoot in focus.
[0039]
The flowchart (steps S101 to S107) in FIG. 8 shows the above-described processing.
In addition, although acquisition of each image data of FIG.7 (b), (c) was performed by sensitivity switching, you may change and change integration time and may input.
[0040]
As described above, according to the multi-AF camera according to the present embodiment, an accurate image signal can be obtained even for a subject having a large contrast, so that accurate ranging can be performed for each point, and the accuracy of the main subject can be accurately determined. Can be selected and focused.
[0041]
In addition, if distance measurement is performed with a missing image signal, an error occurs in the distance. If the result with an error indicates the closest distance, for example, if the focus is given priority in the flow of selecting the closest distance, the photograph will be completely out of focus. Therefore, there is an application technique that raises the distance measurement accuracy by changing the distance measurement point based on the image signal, instead of simply selecting the closest distance. However, since appropriate data can be obtained from the image signal used in this case by the method of the present embodiment, such application and device can be more effectively performed.
[0042]
The fourth embodiment of the present invention will be described below. For the integration control of the multi-AF camera, a device as shown in FIG. 9 can be used. FIG. 9A illustrates a configuration of the light receiving lens 1 and the sensor array 2 that can measure a plurality of points of L, C, and R in the screen described above. As a hardware configuration, For each of the points L, C, and R, monitor circuits 12a to 12c for detecting the maximum integration are attached. One of the monitor circuits 12 a to 12 c is selected by the switching means 5 under the control of the CPU 10, and the output of the selected monitor circuit is input to the comparison means (COMP) 6. The CPU 10 determines the integration end timing based on the comparison result of COMP6. Other functional blocks are the same as in FIG.
[0043]
In such a configuration, when the monitor 12b is selected to measure the distance as shown in FIG. 9B and integration control is performed in the central area C, the person 9a becomes a shadow. Since the integration is completed with the light of, an image signal as shown in FIG. 10A is obtained. On the other hand, when the monitor 12c is selected and integral control of the left area L (tree shadow) is performed, sensor data as shown in FIG. 10B is obtained. At this time, since the dark tree shadow light is integrated to a predetermined level, the integration time becomes long, and an image of the person 9a that has been a shadow that could not be obtained in the central area C is also obtained (FIG. 10 (c). )).
[0044]
That is, in order to obtain a shadow image of the central person 9a, it is not always necessary to select the central area C and perform integration determination. In some cases, another area of the multi AF (in this case, the left There are cases where integral control for area L) is preferred. In such a scene, distance measurement of each point can be performed correctly in the flow as shown in FIG.
[0045]
First, in S40 to S43, integration control is performed using the monitor 12b in the central area C where the existence probability of the main subject is high. That is, the integration is started using the central area C as a determination area, and the integration is terminated when a predetermined level is reached. Next, distance measurement is performed for three points using the obtained sensor data (S44, S45). At this time, sensor data as shown in FIG. 10A is obtained, but since there is almost no image data in the left area L, accurate distance measurement cannot be performed. In such a case, the contrast of the image signal and the degree of coincidence of the images on the two sensor arrays are determined. An inaccurate distance measurement result can be removed by reliability determination.
[0046]
As a result of the reliability determination, for example, as shown in FIG. 10A, the central portion of the central area C is 0, and it is determined in S46 whether the sensor data is inappropriate for distance measurement. To do. From these results, if it is determined that it is better to perform integration once again to capture an image, the process branches from S47 to S48, and the area with the darkest subject is set as a determination area for integration control.
[0047]
In this case, the area L on the left in FIG. 9B is selected and becomes an integral monitor region. In S49 to S53, the sensor data of the integration result obtained in this way is used as an image signal, and distance measurement is performed at three points in the same manner as in steps S40 to S45. Also in this case, it is determined by the reliability determination whether the sensor data in each of the L, C, and R areas is appropriate for distance measurement, so that an inappropriate distance measurement result can be removed.
[0048]
S61 determines the sensor data state of the central area where the probability that the subject exists is particularly high, and the data in a certain part is 0 as in the central area C of FIGS. 10 (a) and 10 (b). If saturated, the process branches to S63 in S62, and the data are synthesized (see FIG. 5), and the distance of the center area C is measured in S64 according to the sensor data. Of the distance measurement data obtained in steps S45, S53, and S64 in this manner, the data with low reliability is removed, and the focus distance is selected recently in S66.
[0049]
As described above, in the present embodiment, the sensor data that is optimal for distance measurement is not necessarily obtained as a result of integration control of each AF point for each distance measurement point, but the integration results for a plurality of times. Select and use.
[0050]
In addition, when data is missing, a plurality of sensor data obtained as a result of the plurality of integration controls are combined and combined to provide a multi-AF autofocus camera capable of more accurate distance measurement.
[0051]
The concept of this embodiment can be applied not only to the composite image of the two integration results described above but also to distance measurement using the composite image of the integration results of three times and four times. Furthermore, although the multi-point type has been described with respect to the multi-AF, the same concept can be applied even when the number of distance measurement points is increased, such as 5 points or 7 points.
[0052]
Next, a fifth embodiment of the present invention will be described. In the embodiment described above, a long sensor array having a large number of sensors is used for three-point distance measurement. However, as shown in FIG. 12, three sensor arrays prepared for L, C, and R may be used. Good. In the flow of FIG. 11, the focusing distance is selected from the seven distance measurement results, but the image signal is detected before the distance measurement according to the image signal state at that time using the image signal state detection means 22 shown in FIG. It may be switched by determining whether or not to measure the distance.
[0053]
First, the switch 5a of the integral amplification switching means 5 is switched to the X side, and the amplification integration operation based on the sensor 2a is started in the low sensitivity mode. Next, the switch 4a of the reading unit 4 is switched by the switching unit 23, and the state of the image signal for each of L, C, and R is sequentially detected by the image signal state detection unit 22. The control means 20 determines the darkest area based on the signal from the image signal state detection means 22. That is, one of L, C, and R is selected.
[0054]
Next, the switch 5a of the integral amplification switching means 5 is switched to the Y side to enter the high sensitivity mode, and the switch 4a is switched by the switching means 23 to match the selected sensor. After such setting, another amplification integration operation is started. Then, the distance measuring means 21 performs distance measurement.
[0055]
FIG. 13 is a block diagram illustrating an operation for synthesizing new sensor data from the sensor data obtained by switching the integration state. These functions are actually realized according to the execution of the program written in the ROM in the one-chip microcomputer. Here, in order to visualize the movement of signals and data, each function is displayed as a block here. Yes.
[0056]
13 have already been described as a light receiving lens, a sensor array, and amplification integration means. The sensor data of each sensor array after switching the amplification integration means is stored in the memories 30a, 30b, 31a, 31b of the storage means 35, respectively. This may be a RAM in the CPU, or a dedicated memory may be used. Which sensor data is put in which address is controlled by the address setting means 36.
[0057]
Low-sensitivity data as shown in FIG. 5A is stored in 30a and 31b, and higher-sensitivity data as shown in FIG. 5B is stored in 30b and 31a. For low-sensitivity data, offset addition units (OFF) 32a and 32b add offset values due to differences in integration characteristics such as the amplification factor described in FIG. When the image signal determination unit 33 detects a portion where the sensor data is 0 and the address setting unit 36 designates an address corresponding to this portion, the area corresponding to the address of the synthesized data RAM 34 has a high sensitivity data region. Data in the memories 30b and 31a is transferred and stored.
[0058]
In addition, when the sensor data is other than 0, the offset value is added to the data stored in the low-sensitivity memories 30a and 31b and transferred to the RAM 34. In this case, since the address is set according to the sensor number, finally the synthesized data as shown in FIG. The synthesized data obtained in this way can detect the subject image in a dynamic range that exceeds the hardware dynamic range of the circuit, increasing the degree of freedom in circuit design and providing a scene with high contrast between light and dark. In this case, accurate distance measurement is possible.
[0059]
The composite data is 16 bits when the original sensor data is 8 bits, but may be stored in a form that is compressed by appropriate division when stored on the RAM 34.
[0060]
As described above, according to the present embodiment, since distance measurement is performed in the optimum image data state for each point according to the brightness of the distance measurement point, highly accurate distance measurement can be performed for each point. In addition, since new combined data is created from two image data by the above-described data combining and the images of the two sensor arrays are compared, distance measurement can be performed without error even at the point where the luminance is switched.
[0061]
As described above, in the present embodiment, when integrating the sensor array for the passive type distance measuring device, the gain switching function at the time of integration and the function of switching a plurality of areas that can be measured are used together. The image signal of the subject can be obtained more accurately and simply, and this enables high-precision distance measurement.
[0062]
The specific embodiment described above includes an invention having the following configuration.
(1)
In a camera with a multi-ranging function that detects object image signals existing in a plurality of areas in a photo screen using an image sensor, performs distance measurement of the plurality of areas using this, and focuses.
Integral amplification switching means for switching the integration or amplification state of the output of the image sensor in order to fit the image signal within a predetermined dynamic range;
Switching means for switching the integral amplification switching means in at least two stages during the subject distance measurement;
And a selection unit that determines the image signal states of the plurality of areas in each integral amplification state and selects the focusing distance from the distance measurement results of the plurality of areas.
(2)
A sensor for detecting the luminance distribution of the subject as an image signal;
Amplifying and integrating means for amplifying and integrating the output signal of the sensor;
Switching means for switching sensitivity characteristics of the amplification integrating means;
After driving the amplification integration means and measuring the time when the output of the amplification integration means becomes a predetermined value, the sensitivity of the amplification integration means is switched based on the time measurement result, and the amplification integration means is driven again. Control means for causing
A computing means for computing a subject distance based on an output signal of the amplification integrating means;
Ranging device having
(3)
A distance measuring apparatus according to (1), comprising combining means for combining the output signals of the amplification and integration means driven at different sensitivities to generate a combined signal, and calculating a subject distance based on the combined signal.
(4)
The control means switches the sensitivity of the amplification integration means to high sensitivity and switches the amplification integration means again when the output of the first drive of the amplification integration means exceeds the dynamic range of the amplification integration means. The distance measuring device of (2) or (3) to be driven.
(5)
When the control means detects that the main subject is in the backlight state, the sensitivity of the amplification integration means is switched to high sensitivity and the amplification integration means is driven again (2) or (3) distance measurement apparatus.
(6)
The distance measuring apparatus according to (4), wherein the control means determines a backlight state based on an output obtained by driving the first amplification integration means.
(7)
A sensor for detecting the luminance distribution of the subject as an image signal;
Amplifying and integrating means for amplifying and integrating the output signal of the sensor;
Switching means for switching the operating time of the amplification integrating means;
Combining means for combining the output signal when the amplification integration means is driven for a predetermined time and the output signal when the operation time is switched by the switching means to generate a combined signal;
A computing means for computing the subject distance based on the combined signal;
Ranging device having
(8)
The synthesizing unit adds the offset value to one of the output signals from the amplification integrating unit, and synthesizes by writing only valid data of both output signals to a predetermined address on the memory (3) or (7) Distance measuring device.
(9)
The distance measuring apparatus according to (3) or (7), wherein the arithmetic means performs reduction conversion on the combined signal and calculates a subject distance based on the converted signal.
(10)
The distance measuring device according to (3) or (7), wherein the sensor detects image signals of a subject existing in a plurality of areas of the object scene.
(11)
A sensor array that integrates and detects image signals of subjects existing in a plurality of areas of the object field, and a monitoring means that can monitor by switching the integration state for each area of the sensor array corresponding to the plurality of areas. In a camera distance measuring device having
Measurement means comprising control means for controlling a switching state of the monitoring means when the integration operation is performed again based on an image signal pattern obtained in accordance with an integration monitoring state for a predetermined area of the sensor array. Distance device.
(12)
The distance measuring device according to (11), wherein the control means determines the darkest area based on the image signal pattern, switches the monitoring means to the area, and performs the integration operation again.
[0063]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the contrast of a to-be-photographed object can be obtained even at the time of backlight with a simple structure, and the ranging apparatus which can perform a high-speed and accurate ranging can be provided.
Regardless of whether the scene is backlit or not, even if the luminance distribution of the subject is large and a correct image signal cannot be obtained beyond the dynamic range of the circuit, high-accuracy measurement is possible that enables accurate distance measurement. A distance device can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.
FIG. 2A shows an integrated waveform when light from a high-luminance subject portion is received, and FIG. 2B shows an integrated waveform when light from a low-luminance subject portion is received. .
3A is a diagram showing a waveform of an image signal in a low sensitivity mode, and FIG. 3B is a diagram showing a waveform of an image signal in a high sensitivity mode.
FIG. 4 is a flowchart showing details of integration control according to the first embodiment of the present invention.
FIG. 5 is a conceptual diagram for explaining an outline of a second embodiment of the present invention.
FIG. 6A is a flowchart showing details of integration control according to the second embodiment of the present invention, and FIG. 6B is a diagram showing how sensor data is stored in a RAM.
FIG. 7 is a diagram for explaining an outline of a third embodiment of the present invention.
FIG. 8 is a flowchart showing the operation of the third exemplary embodiment of the present invention.
FIG. 9A shows the configuration of the fourth embodiment of the present invention, and FIG. 9B shows a shooting scene.
FIG. 10 is a diagram for explaining an outline of a fourth embodiment of the present invention.
FIG. 11 is a diagram for explaining the operation of the fourth embodiment of the present invention.
FIG. 12 is a diagram showing a configuration of a fifth exemplary embodiment of the present invention.
FIG. 13 is a block diagram illustrating an operation of synthesizing new sensor data from sensor data obtained by switching the integration state.
[Explanation of symbols]
1a, 1b ... light receiving lens,
2a, 2b ... sensor array,
3 ... Amplifier (AMP),
4 Reading means,
5 ... switching means,
6 ... Comparison means (COMP),
7 ... Timer,
8 ... scene,
9 ... Subject,
10: CPU.

Claims (1)

A plurality of pairs of sensor arrays for detecting the luminance distribution of a subject existing in a plurality of areas in the screen as an image signal ;
An amplifier integrating means for amplifying integrating the output signal of the upper Symbol pairs of sensor arrays,
Integral amplification switching means for switching the sensitivity characteristic of amplification or integration to at least two stages;
An image signal state detection means capable of detecting an integration state by an output of the amplification integration means for each of the plurality of pairs of sensor arrays;
Switching means for switching the output of the amplification integration means for each of the plurality of pairs of sensor arrays and outputting the output to the image signal state detection means;
In a distance measuring device comprising calculation control means for calculating information related to the distance to the subject according to image signal positions based on the plurality of pairs of sensor array outputs,
The arithmetic control means switches the switching means for the output signals of the plurality of pairs of sensor arrays which are amplified and integrated by switching the amplification or sensitivity characteristics by the amplification integration means so that the amplification factor or sensitivity is lower. Based on the detection result of the image signal state detection means, the sensor array of the output signal showing the lowest luminance is discriminated and selected, and then the amplification integration means of the sensor array of the output signal showing the lowest luminance is selected. The switching means is set so that the image signal state detection means detects the output, and the amplification or sensitivity characteristic is switched by the integral amplification switching means so that the amplification factor or sensitivity is higher, and the amplification integration Obtained for the selected sensor array by amplifying and integrating the output signal of the selected sensor array for the same subject by means The different image signals amplification or sensitivity characteristics one subject was synthesized with the exception of invalid data of which, combined distance measuring apparatus and obtaining the information related to the object distance based on the image signal.

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