JP3146782B2 - CCD sensor for moving objects - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CCD sensor for a moving object,
Particularly, a pair of CCs provided in a predetermined position of the vehicle in a vertical direction.
The present invention relates to a CCD sensor that detects a distance to a surrounding object using D.

[0002]

2. Description of the Related Art Conventionally, various devices have been developed and mounted in order to reduce the driving operation of a driver, and a system for detecting a distance between the vehicle and a preceding vehicle to notify a danger or for controlling a vehicle speed. Has also been developed. For example, as shown in FIG. 7, a pair of CCDs 10 and 1 are located at predetermined positions in the front of the vehicle.
2 are arranged in a vertical direction at a predetermined interval, and these CCDs
By calculating the phase difference between the images obtained in steps 10 and 12, the inter-vehicle distance is detected based on the principle of triangulation (JP-A-3-165212).

FIG. 8 shows a more detailed configuration of the CCDs 10 and 12. Since the CCDs 10 and 12 have the same configuration, the CCD 10 will be described below for convenience of explanation. As is well known, the CCD includes a plurality of light receiving elements (photodiodes) 10a arranged in a matrix, a vertical transfer CCD for vertically transferring charges accumulated in the plurality of light receiving elements, and a transfer from the vertical transfer CCD. It is configured to include a horizontal transfer CCD 10b for sequentially outputting the discharged charges to the outside of the CCD sensor. Then, the inter-vehicle distance is detected by calculating the phase difference between the image signals output from the CCDs 10 and 12. To detect the inter-vehicle distance in a short time, the image signals from all the light receiving elements in the CCDs 10 and 12 are detected. It is not advisable to use.
Therefore, in the related art, as shown in FIG. 8, among a plurality of light receiving elements 10a arranged in a matrix, a plurality of light receiving elements 10a arranged on a predetermined line in a vertical direction (parts indicated by oblique lines in the figure) The phase difference is calculated by using the image signal of (1). For this reason, the horizontal transfer CCD 10b
The thinning circuit 14 is used to supply only the image signal used for the phase difference calculation to the subsequent processing means among the image signals transferred from. The decimating circuit 14 receives the clock signal (10 to 20 M) from the clock CLOCK 16.
Hz), and removes unnecessary image signals to remove A /
D18. Then, the image signal converted into a digital signal by the A / D 18 is stored in a RAM as a storage means, and the above-described phase difference calculation is performed. FIG. 9 shows a configuration of an inter-vehicle distance detecting device including a processing means for calculating a phase difference, and FIG. 10 shows the operation thereof. As described above, the image signals from the CCDs 10 and 12 are removed of unnecessary image signals by the thinning circuit 14, converted into digital signals by the A / D 18, and stored in the RAM 20. Therefore, the RAM 20 needs a sufficient capacity to store data for one image of each of the CCDs 10 and 12. After all the image data is stored, the CPU 22 for controlling the system
ASIC (Application Spec)
A correlation operation for calculating the phase difference is performed in the integrated circuit 24. A program for this correlation operation is stored in the ROM 26 in advance. And
Based on the calculated phase difference, the inter-vehicle distance is calculated according to a predetermined calculation formula, and output via the I / O 28.

When processing signals from the CCDs 10 and 12, two horizontal lines are processed as a set within a predetermined time (for example, 1/60 second), and within a next predetermined time, one horizontal line is processed. Interlace scanning for processing a set of horizontal lines shifted by lines is mainly used. By this interlace operation, the inter-vehicle distance data is calculated every 1/30 second, and the accuracy of the inter-vehicle distance data is proportional to the pitch interval of the CCD.

[0005]

However, in this conventional apparatus, as shown in FIG.
Of the light receiving elements in the inside, the light is sequentially transferred from the light receiving element line vertically below, so that the problem of blooming may occur. That is, when the images formed on the CCDs 10 and 12 are set to the optical elements as shown in FIG. 11, a relatively bright area of the sky area is formed on the light receiving element vertically above the light receiving element. , 12, a relatively dark area including the vehicle is imaged. Accordingly, the amount of charge of the light receiving element located in the region vertically above (indicated by a in the figure) is large, while
The amount of charge of the light receiving elements located vertically below the CCDs 10 and 12 (indicated by b in the figure) is small. Therefore, as shown in FIG. 12, the CCD output in the area a is large and the CC output in the area b is large.
The D output decreases. Here, if the amount of light in the region a is equal to or more than a predetermined amount, an overflow of electric charges occurs. If data is read vertically below, the data after the overflowing light receiving element is affected, and accurate electric charges are generated. A problem arises in that the quantity cannot be output.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a CCD sensor for a moving body capable of always performing high-accuracy distance measurement regardless of the surrounding environment. It is in.

[0007]

According to a first aspect of the present invention, there is provided a moving object CCD sensor comprising a plurality of light receiving elements arranged in a matrix and forming one sensor; There is a charge readout unit for reading out the stored image data, and a data processing unit for analyzing the image data, wherein the charge readout unit sequentially reads out from the light receiving element which has taken an image of the vicinity of the ground.

In order to achieve the above object, a moving object CCD sensor according to a second aspect of the present invention is the moving object CCD sensor according to the first aspect, wherein the charge reading means is arranged on a predetermined vertical line. A transfer CCD arranged in a vertical direction for sequentially outputting image data transferred from the received light receiving element, and reading image data vertically upward from the transfer CCD arranged in the vertical direction.

According to a third aspect of the present invention, there is provided a CCD sensor for a moving object according to the first aspect, wherein the charge reading means is arranged on a predetermined vertical line. A first transfer CCD provided in a vertical direction for each of the light receiving elements, and a second transfer CCD for sequentially outputting image data transferred from the first transfer CCD.
A transfer CCD, and a second transfer C from the first transfer CCD.
The transfer to the CD is performed vertically upward.

[0010]

In the above construction, the moving object CCD sensor of the present invention sequentially reads out the image data stored in the light receiving element from the data near the ground surface, that is, the vehicle image side data having a relatively small CCD output. And accurate distance measurement becomes possible.

A CCD for a moving object according to a third aspect of the present invention.
In the sensor, a transfer CCD (first transfer CCD) is provided for each predetermined line in the vertical direction. Therefore, when image data is read from a certain vertical line, the influence of the charge amount of the immediately preceding vertical line is reduced. There is no fear.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
A preferred embodiment of the CD sensor will be described.

First Embodiment FIG. 1 shows CCDs 30 and 32 in this embodiment. Similar to a conventional CCD, a plurality of light receiving elements are arranged in a matrix, and only light receiving elements arranged on a predetermined line in the vertical direction are used for distance measurement (a hatched portion in the figure). The CCDs 30 and 32 of the embodiment are characterized in that horizontal transfer CCDs that sequentially output image signals to the outside in the conventional CCD are arranged in the vertical direction, and constitute the transfer CCDs 30a and 32a. As described above, by vertically arranging the transfer CCDs that sequentially output the charge amounts accumulated in the light receiving elements, data from the distance measuring light receiving elements arranged on a predetermined vertical line can be eliminated. Direct output is possible. That is, in the figure,
Based on the clock signal from the clock CLOCK, the charge amount from the distance-measuring light-receiving element on the vertical line located at the left end is transferred to the transfer CCDs 30a and 32a, directly output to the A / D as it is, and converted into a digital signal. Is output. Since data from the light receiving element on the next line is not used for distance measurement, the clock CLOCK is used.
The operation of the A / D 18 is stopped based on the clock signal from the CPU and the image signal is not output as a digital signal even if the image signal is supplied from the transfer CCDs 30a and 32a. When the image signal of the fourth line is transferred to the transfer CCDs 30a and 32a, this line is used as distance measurement data, so that the A / D 18 is operated based on a clock signal to convert the signal into a digital signal and output it. In this manner, a thinning circuit, which is conventionally required for high-speed operation (10 to 20 MHz), is not required.
The image data output from the CCDs 30 and 32 and converted into digital signals by the A / D 18 is supplied to the CPU 34 as shown in FIG. 2, where a correlation operation is performed to calculate a phase difference. After the inter-vehicle distance is calculated using the phase difference, the distance is supplied to a notification device 36 such as an alarm device or a display device.

FIG. 3 shows the configuration of the CPU 34 in the present embodiment, and FIG. 4 shows the operation of the CPU 34. CPU 34 in the present embodiment
Are two memories RAM1 and RA2 for storing image data.
M2 that performs a correlation operation by using the image data stored in the RAM1 and the RAM2 alternately.
And IC 34a. This ASIC 34a is RO
The correlation calculation is performed according to the calculation program stored in M34b, the calculation of the following distance is further performed, and the following distance data is output to the notification device 36.

The RAM 1 and the RAM 2 do not need a capacity for storing image data for one screen of the CCDs 30 and 32, and need only have a capacity for storing only one line of image data, unlike the conventional apparatus. And CCD30,
The image data of a certain 32 lines is stored in the RAM 1,
While the stored data is read and the ASIC 34a performs the correlation operation, the CPU stores the image data of the next line of the CCDs 30 and 32 in the RAM 2 and prepares for the next correlation operation. When the correlation operation is completed using the image data stored in the RAM 1, the ASIC 34a directly accesses the RAM 2 and performs the correlation operation on the next line using the data stored (DMA). Then, while the ASIC 34a performs the correlation operation using the data stored in the RAM 2, the RAM 1 further stores the image data of the next line and prepares for the correlation operation. In this manner, the image data is stored in the RAMs 1 and 2 alternately,
By performing the correlation operation alternately by the SIC 34a,
Correlation calculation is performed for each line, and inter-vehicle distance data is output.

FIG. 4 shows the alternate storage of the image data and the cross-correlation calculation by the ASIC 34a. In the figure, double circles indicate that image data from the CCDs 30 and 32 are stored, and squares indicate that the ASIC 34a performs a correlation operation using the stored data. As can be easily understood from the figure, the RAMs 1, 2
Stores image data from the CCDs 30 and 32 alternately,
Further, the ASIC 34a is alternately accessed to perform the correlation operation. Thereby, RAM1 and RAM2 are CCD
It is not necessary to have enough capacity to store one screen of image data from 32. Only the capacity to store one line of image data is required. Also, since inter-vehicle distance data can be obtained for each line, high-speed processing can be performed. It becomes possible.

Further, in the present embodiment, the CCD 30,
The image data is output to the A / D 18 vertically upward from the 32 transfer CCDs 30a and 32a. As previously mentioned,
Of the light-receiving elements of the CCD, the lower region where the sky region forms an image has a large amount of light, so that the amount of charge is large, while the upper region where the vehicle forms an image has a relatively small amount of light and a small amount of charge. Therefore, in the configuration in which the charge is output from the lower region as in the conventional device, a problem such as blooming occurs. However, as in the present embodiment, the transfer CCD is arranged in the vertical direction, and the charge is transferred vertically upward. By outputting the signal to the outside, the signal is output from the vehicle having a small charge amount, so that the influence of blooming due to the overflow of the charge can be removed, and the distance measurement can be reliably performed in any surrounding environment.
FIG. 5 shows the reading direction from the CCDs 30 and 32 in the present embodiment. Compared with the conventional reading direction shown in FIG. 12, the effectiveness of the reading direction in the present embodiment can be understood. There will be.

Second Embodiment In the first embodiment described above, the transfer CCDs 30a and 32
Although a is provided for each of the pair of CCDs 30 and 32, in this embodiment, a vertical transfer CCD is provided for each predetermined vertical line.

FIG. 6 shows the structure of one CCD 40 of the pair of CCDs in this embodiment. As in the first embodiment, a plurality of light receiving elements are arranged in a matrix, and only light receiving elements arranged on a predetermined line in the vertical direction are used for distance measurement (parts indicated by oblique lines in the figure). In the CCD 40 of the present embodiment, one vertical transfer CCD 40a is provided for each line, and image data from a light receiving element on the line is transferred. And
A horizontal transfer CCD 40b to which image data from the transfer CCD 40a is transferred is provided above the CCD 40, that is, above the transfer CCD 40a. Since image data is transferred vertically upward from the transfer CCD 40a to the horizontal transfer CCD 40b, the effect of blooming due to charge overflow can be eliminated as in the first embodiment.

Further, in this embodiment, since the vertical transfer CCD 40a is provided for each vertical line, reading of one vertical line is completed, and when reading the next vertical line, the previous vertical line is read. It is possible to perform more accurate distance measurement without being affected by the overflow of the charge.

[0021]

As described above, according to the CCD sensor for a mobile object of the present invention, the influence of blooming or the like can be prevented.
High-precision distance measurement can be performed regardless of the surrounding environment.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a CCD sensor according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a moving object CCD sensor in the embodiment.

FIG. 3 is a configuration diagram of a CPU in the embodiment.

FIG. 4 is an explanatory diagram of an operation of a CPU in the embodiment.

FIG. 5 is an explanatory diagram showing an image signal output direction (readout direction) of the CCD sensor in the embodiment.

FIG. 6 is a configuration diagram of a CCD sensor according to another embodiment of the present invention.

FIG. 7 is a configuration diagram when a CCD sensor is mounted on a vehicle.

FIG. 8 is a configuration diagram of a CCD sensor in a conventional device.

FIG. 9 is an overall configuration diagram of a conventional device.

FIG. 10 is an explanatory diagram showing the operation of the conventional device.

FIG. 11 is an explanatory diagram showing an area where an image is formed on a CCD sensor.

FIG. 12 is an explanatory view showing an image signal output direction (readout direction) from a CCD sensor in a conventional device.

[Explanation of symbols]

 10, 12, 30, 32 CCD 14 Thinning-out circuit 18 A / D 34 CPU 36 Notification device

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ identification symbol FI // G05D 1/02 G05D 1/02 S (58) Field surveyed (Int.Cl. ⁷ , DB name) G01C 3/00- 3/32 B60R 21/00 621 G06T 1/00 280 G06T 1/00 420 G08G 1/16 G05D 1/02

Claims (3)

(57) [Claims] 1. A single sensor arranged in a matrix
A plurality of light receiving elements constituting a charge reading means for reading the image data accumulated in the light receiving element, has a data processing means for analyzing the read out image data, the charge reading means a near surface A CCD sensor for a moving body, wherein the CCD is sequentially read from a light receiving element that has been imaged. 2. The CCD sensor according to claim 1, wherein said charge readout means is arranged in a vertical direction for sequentially outputting image data transferred from a light receiving element arranged on a predetermined vertical line. A transfer CCD arranged in a vertical direction and reading image data vertically upward from the transfer CCD arranged vertically.
CD sensor. 3. The CCD for moving objects according to claim 1, wherein said charge readout means is provided in a vertical direction for each light receiving element arranged on a predetermined vertical line.
And a second transfer CCD for sequentially outputting image data transferred from the first transfer CCD, and the transfer from the first transfer CCD to the second transfer CCD is performed vertically upward. CCD sensor for moving objects.