JPH11287649A - Vehicle-to-vehicle distance detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the failure diagnosis of a CCD sensor without using a bonnet signal by comparing the image data stored in a second memory for storing the content of a first memory at a prescribed timing every same address, and storing the address having no change in a third memory together with its frequency. SOLUTION: A microcomputer reads an image signal to a RAM 13, and shifts the image signal stored in the RAM 13 to a RAM 14 at a prescribed timing. The image signal stored in the RAM 13 is displayed on an indicator, and a CPU 15 compares the same address of the image data stored in the RAM 13 and RAM 14 every address to judge whether it is the image data having the same illuminance or not. Thereafter, the CPU 15 reads the address and the corresponding frequency in order of number, and when the illuminance is coincident with that from a photodetector corresponding to the same address, 1 is added to the corresponding frequency and stored in a RAM 19. It is checked whether the frequency of each address exceeds a prescribed value or not to perform a failure display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle distance detecting apparatus, and more particularly to a failure diagnosis of an inter-vehicle distance detecting apparatus using a CCD sensor.

[0002]

2. Description of the Related Art Conventionally, this kind of inter-vehicle distance detecting apparatus is shown in FIG.
This will be described with reference to Japanese Patent Application Laid-Open No. 6-229557.
In the figure, anamorphic lenses 3 and 4 that produce images having different magnifications in the horizontal and vertical directions on the image plane are arranged in front of the optical axes of the CCD sensors 1 and 2. The front vehicle image and the hood image formed by the CCD sensors 1 and 2 are converted into electric signals, converted into digital signals by A / D converters 5 and 6, and stored in the RAM 7. RAM7
The digital image information stored in the CPU 9 and the ASIC according to a processing program stored in the ROM 8 in advance.
10 to calculate the inter-vehicle distance, and perform differentiation processing of the obtained image signal to obtain the CCD sensors 1 and 2.
Of the hood signal is detected at a predetermined position, and the presence or absence of a failure is detected.

That is, as shown in FIG. 7, since the luminance changes discontinuously at the boundary between the background image and the bonnet image, the differential output also shows a peak value at the boundary of the bonnet. Therefore, the CPU 9 can detect the presence or absence of the bonnet signal by differentiating the image information stored in the RAM 7 and detecting whether or not there is a peak at a predetermined position. When the hood signal is detected, it is determined that the CCD sensors 1 and 2 are operating normally.

On the other hand, if no bonnet signal is detected, it is determined that a failure has occurred in the CCD sensors 1 and 2 or other optical systems, and the CPU 9 notifies the operator via an alarm device installed near the driver's seat. .

[0005]

However, in the inter-vehicle distance detecting apparatus described above, an image of the hood is taken by the CCD sensor, and whether or not the CCD sensor is normal depends on whether or not the hood signal is obtained. Therefore, when the optical axis of the CCD sensor is directed far away and an image of the hood cannot be obtained, there is a problem that the failure diagnosis of the CCD sensor cannot be performed.

Therefore, the present invention has been made in view of the above-mentioned problems, and has been developed by using a CCD without using a bonnet signal.
It is an object of the present invention to provide a device capable of performing a failure diagnosis of a sensor.

[0007]

According to the present invention, there is provided a vehicle distance detecting device comprising a plurality of light receiving elements arranged in a lattice, and a pair of CCD cameras for imaging a vehicle ahead.
A first memory for storing image data for one screen from the pair of CCD sensors, and image data from the pair of CCD sensors stored in the first memory, respectively, and a shift amount of the image data And an arithmetic unit for detecting the inter-vehicle distance to the preceding vehicle on the basis of the amount of deviation, and reads and stores the contents of the first memory at a predetermined timing.
A memory, wherein the arithmetic unit compares the image data stored in the first and second memories for each same address,
If there is no change in the image data, the address where the change has not occurred is stored in the third memory together with the number of times the change has not occurred. When it is determined that the number of times the address in the vicinity of the address has not changed is also greater than the predetermined number, a signal indicating that the light receiving element has failed is output.

In the vehicle distance detecting apparatus according to the present invention, the timing at which the second memory reads the contents stored in the first memory is longer than the timing at which the first memory reads from the pair of CCD sensors. It is characterized by.

The vehicle distance detecting apparatus according to the present invention is characterized in that an address near the address where the storage circuit is larger than a predetermined circuit is near in the positional relationship of the elements on the CCD sensor.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIG. First, the outline is C
The front vehicle images (for example, FIG. 2 and FIG. 3) captured by the CD sensors 11 and 21 are converted into electric signals, and A / A
The digital signals are converted by the D converters 12 and 22 into
It is stored in the RAM 13 and the second RAM 14. The digital image information stored in the first and second RAMs 13 and 14 is read out by the CPU 15 and the ASIC 16 according to a processing program stored in the ROM 17 in advance to calculate the following distance.

Next, the CCD sensor 1 will be described in detail.
Reference numerals 1 and 21 denote optical axes that are positioned substantially parallel to the road and are set at angles such that an image of the hood of the own vehicle is not captured. For example, as shown in FIGS. Only the image is set to be taken. As the vehicle moves, even the same object is not always imaged in the same state, so that the intensity of light received by each of the light receiving elements arranged in a matrix changes each time an image is picked up.

12 and 22 are first and second A / D converters,
Reference numerals 13 and 14 denote first and second RAMs (memory) which store the latest image data in the first RAM 13 among the image data supplied from the first and second A / D converters 12 and 22 for each screen. In addition, the image data stored in the first RAM 13 is stored in the second RAM at a predetermined timing.
Store it in AM14.

Reference numeral 15 denotes a CPU which reads a processing program stored in the ROM 17 in advance while complementing each other with the ASIC 16, and according to the read processing program, a pair of CCDs stored in the first RAM 13.
The image data obtained from the sensors 11 and 21 are compared with each other to compare the deviation amounts of the image data of the preceding vehicle, and the deviation amount of the images is calculated to calculate the inter-vehicle distance. Also CPU
15 is stored in the first and second RAMs 13 and 14,
Two image data obtained from one CCD sensor 11 (or 21) at different imaging timings are compared for each address of the light receiving element, and if they match, the number of times described in FIG. 4 corresponding to the matched address 1 in the numerical value of the term
Is added, and the added numerical value is stored in correspondence with the address of the third RAM 19. Further, the CPU 15
The numerical value of the number of times stored in the third RAM 19 is always compared with a predetermined number. If the numerical value exceeds the predetermined value, it is determined that the light receiving element corresponding to the address is destroyed, and the damaged light receiving element is determined. When there are a plurality of light receiving elements on the screen, that is, at locations where the light receiving elements of the CCD sensors 11 and 21 are arranged and concentrated, the reliability of the light receiving data is high. Is not secured, a signal indicating that the CCD sensors 11 and 21 have failed is output.

In the third RAM 19, as shown in FIG. 4, an address is set corresponding to each of the light receiving elements of the CCD sensors 11 and 21, and the number of matches is stored corresponding to the address. It has become.

The operation of the above configuration will be described with reference to FIG. The microcomputer controls the first and second A / D converters 12 and 22 to transmit a video signal, which is a light receiving signal, to a first RAM.
13 and the video signal stored in the first RAM 13 is shifted to the second RAM 14 at a predetermined timing (step ST1). Next, the video signal stored in the first RAM 13 is displayed on a display (not shown) (step ST2), and the CPU 15 assigns the same address of the video data stored in the first RAM 13 and the video data stored in the second RAM 14. A comparison is made for each address to determine whether or not the video data has the same luminance (step ST3). Thereafter, the CPU 15 reads the address and the number of times corresponding to the address from the third RAM 19 in numerical order, and when the luminance from the light receiving element corresponding to the same address as the read address is the same, the number of times corresponding to the same address. 1 is added to (see FIG. 4) and stored in the third RAM 19 (step ST4). Thereafter, it is checked whether the number of times of each address stored in the third RAM 19 has exceeded a predetermined value, and when it is determined that the light receiving elements corresponding to a certain range of addresses have failed together, the CCD sensor is displayed on the display. It is displayed that 11 or 12 is out of order (step ST5).

Embodiment 2 In the first embodiment, the addresses corresponding to all the light receiving elements are stored in the third RAM 19 so as to be checked. However, the CPU 15 compares the luminance data stored in the first RAM 13 and the luminance data stored in the second RAM 14 for each same address. In this case, only when it is determined that the luminance is the same, the address is stored in the third RAM 19, and the number of times is further updated. If there is no data, the memory capacity can be reduced by automatically deleting the data.

In the above embodiment, the second RA
The M14 is updated synchronously every time the content stored in the first RAM 13 is updated. For example, the update of the second RAM 14 is reduced to one for ten updates of the first RAM 13 to reduce the signal processing speed. Needless to say, it is possible to reduce the processing and make the processing of the CPU 15 easier. That is,
Since this kind of failure does not occur suddenly and collectively but occurs over a long period of time, for example, compare the data immediately before the last ignition switch off with the data immediately after the current ignition switch on. May be.

[0018]

As described above, according to the first aspect of the present invention, the failure diagnosis of all the light receiving elements can be performed, so that the effect of improving the reliability of data can be exhibited. According to the second aspect of the present invention, the content stored in the second memory is updated in a long cycle in the first memory, so that it is not necessary to increase the signal processing speed of the CPU. According to the third aspect, by checking the failure state of the element adjacent to the CCD sensor, the effect of improving the reliability of data is exhibited.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a circuit block according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining an image from one CCD sensor stored in a first RAM 13;

FIG. 3 is an explanatory diagram for explaining an image from the other CCD sensor stored in a first RAM 13;

FIG. 4 is an explanatory diagram for explaining a storage state of an address and the number of times stored in a third RAM 19;

FIG. 5 is a flowchart illustrating the operation of a CPU 15;

FIG. 6 is a circuit block diagram of a conventional device.

FIG. 7 is a waveform explanatory diagram for explaining a conventional problem.

[Explanation of symbols]

 11, 21 CCD sensor 12, 22, A / D converter 13, 14, 19 RAM (memory) 15 CPU 16 ASIC 17 ROM

Claims (3)

[Claims] 1. A pair of CCD cameras, each of which comprises a plurality of light receiving elements arranged in a grid and captures an image of a vehicle ahead,
A first memory for storing image data for one screen from the pair of CCD sensors, and image data from the pair of CCD sensors stored in the first memory, respectively, and a shift amount of the image data And an arithmetic unit for detecting the inter-vehicle distance to the preceding vehicle based on the deviation amount. A second memory for reading and storing the contents of the first memory at a predetermined timing The arithmetic unit compares the image data stored in the first and second memories for each same address, and when there is no change in the image data, the address where there is no change is not changed. Stored in the third memory together with the number of times that the stored
And outputting a signal indicating that the light receiving element has failed when it is determined that the number of times that the address near the address whose number of storages has become larger than the predetermined number has not changed has also become larger than the predetermined number. An inter-vehicle distance detection device characterized by the above-mentioned. 2. The timing according to claim 1, wherein the timing at which the second memory reads the contents stored in the first memory is longer than the timing at which the first memory reads from the pair of CCD sensors. Inter-vehicle distance detection device. 3. The inter-vehicle distance detecting device according to claim 1, wherein an address near the address at which the storage circuit becomes larger than a predetermined circuit is near in the positional relationship of the elements on the CCD sensor.