JP2012182763A - Image processing apparatus, image display system, and image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect memory while avoiding bank competitions.SOLUTION: In an image display system, a display device has two display modes: a back monitor mode which displays a photographic image and a navigation mode which displays a navigation image that is a non-photographic image other than a photographic image. An image writing part 61 periodically writes a photographic image in a writing bank in the back monitor mode and the navigation mode. In addition, an image reading part 62 periodically reads a photographic image from a reading bank which is different from the writing bank in the back monitor mode only. On the other hand, a memory inspection part 63 inspects a bank to be inspected which is different from the writing bank in the navigation mode only. Since the memory inspection part 63 can select the bank to be inspected without taking the reading bank into consideration, therefore, the memory inspection part 63 can inspect a frame memory 45 while avoiding bank competitions.

Description

  The present invention relates to a technique for processing an image.

  2. Description of the Related Art Conventionally, an image display system that processes an image obtained by a camera and displays the image on a display device is known. As one of such image display systems, for example, there is a vehicle image display system that displays an image obtained by a camera that captures the periphery of the vehicle on a display device provided in the vehicle. By using such an image display system, the user can check the situation around the vehicle in substantially real time.

  In the image display system, the synchronization timing of the video signal obtained from the camera may be different from the synchronization timing of the video signal output to the display device. For this reason, in such an image display system, a frame memory which is a memory capable of storing a plurality of images (frames) is generally used to adjust the synchronization timing of the video signal. An image is periodically written in the frame memory, and the image is periodically read out from the frame memory at a predetermined timing, whereby the synchronization timing of the video signal is adjusted.

  The frame memory is provided with a plurality of banks each capable of storing an image. In the image display system, image writing and image reading are performed individually and periodically, so that the writing bank to which the image is to be written competes with the reading bank to which the image is to be read (that is, The same). If the writing bank and the reading bank compete with each other in this way, an incomplete image during writing may be read. For this reason, the image display system is required to avoid contention between the writing bank and the reading bank.

  Note that there is Patent Document 1 as a document disclosing a technology related to the technology described in this specification.

JP 2007-47426 A

  By the way, when an abnormality occurs in the frame memory, such as when some of the memory cells fail, the image cannot be stored correctly in the frame memory. As a result, an image having a defect such as a lack of a part of the region is displayed on the display device, which may be misunderstood by a user who views the display device. In particular, when such a defective image is displayed in an image display system for a vehicle, the user may make an incorrect determination about the state of the surroundings of the vehicle and may perform inappropriate driving.

  For this reason, it is desirable to periodically inspect whether there is an abnormality in the frame memory. In general, the frame memory is inspected by writing predetermined inspection data to an inspection bank to be inspected and further reading the inspection data from the inspection bank. Therefore, the bank to be inspected needs to be a bank different from both the write bank and the read bank.

  However, it is very difficult to select the bank to be inspected so that the write bank and the read bank do not compete with each other, and also do not compete with both the write bank and the read bank. For this reason, a technique capable of inspecting the frame memory while avoiding such bank competition has been demanded.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of inspecting a memory while avoiding bank conflicts.

  In order to solve the above-mentioned problem, the invention of claim 1 is an image processing device for processing an image to be displayed on a display device, an acquisition means for periodically acquiring a photographed image obtained by a camera, and a plurality of banks And a determination unit that determines whether the display mode of the display device is a first mode for displaying the captured image or a second mode for displaying a non-photographed image other than the captured image. In both the first mode and the second mode, a writing unit that periodically writes the captured image acquired by the acquiring unit to a writing bank selected from the plurality of banks, and the first mode In the second mode, in the second mode, the reading unit periodically reads the photographed image from a reading bank different from the writing bank of the plurality of banks. And a, and inspection means for inspecting the different inspected banks and write bank.

  In addition, the invention of claim 2 is the image processing apparatus according to claim 1, further comprising a notifying means for notifying a user of the occurrence of the abnormality when the inspection means detects an abnormality of the bank to be inspected. ing.

  According to a third aspect of the present invention, in the image processing apparatus according to the second aspect, the camera is an in-vehicle camera that captures the periphery of the vehicle.

  According to a fourth aspect of the present invention, in the image processing apparatus according to the first aspect, the memory further includes a spare bank serving as a spare for the plurality of banks, and the writing unit and the reading unit include: When the inspection means detects an abnormality in the bank to be inspected, the spare bank is used in place of the bank to be inspected.

  According to a fifth aspect of the present invention, in the image processing apparatus according to the fourth aspect, the inspection unit inspects the spare bank in the first mode.

  According to a sixth aspect of the present invention, there is provided an image display system for displaying an image, the image processing apparatus according to any one of the first to fifth aspects, and a display for displaying a photographed image processed by the image processing apparatus. And a device.

  Further, the invention of claim 7 is an image processing method for processing an image to be displayed on a display device, wherein (a) a step of periodically obtaining photographed images obtained by a camera; and (b) the display device. Determining whether the display mode is a first mode for displaying the photographed image or a second mode for displaying a non-photographed image other than the photographed image; and (c) the first and first modes In both of the two modes, the step of periodically writing the captured image acquired in the step (a) into a write bank selected from a plurality of banks of the memory; and (d) in the first mode. A step of periodically reading the photographed image from a reading bank different from the writing bank of the plurality of banks; and (e) in the second mode, the writing bank of the plurality of banks; Is different It includes a step of inspecting the 査 bank, the.

  According to the first to seventh aspects of the invention, since the inspected bank is inspected in the second mode in which the captured image is not read out, the memory can be inspected while avoiding bank conflicts.

  In particular, according to the second aspect of the present invention, the user can recognize that the captured image cannot be displayed normally when a memory abnormality occurs.

  In particular, according to the invention of claim 3, when a memory abnormality occurs, the user can recognize that the state around the vehicle cannot be normally displayed.

  In particular, according to the invention of claim 4, even when a memory abnormality occurs, a normal captured image can be displayed by using the spare bank.

  In particular, according to the invention of claim 5, since the spare bank is inspected in the first mode, the memory can be inspected efficiently.

FIG. 1 is a diagram illustrating a schematic configuration of an image display system. FIG. 2 is a diagram illustrating display mode transition. FIG. 3 is a diagram illustrating a detailed configuration of the image processing apparatus according to the first embodiment. FIG. 4 is a diagram illustrating a processing flow of the image processing apparatus according to the first embodiment. FIG. 5 is a diagram showing the timing of writing and the timing of inspection. FIG. 6 is a diagram illustrating a detailed configuration of the image processing apparatus according to the second embodiment. FIG. 7 is a diagram illustrating a processing flow of the image processing apparatus according to the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<1. First Embodiment>
<1-1. Configuration of image display system>
FIG. 1 is a diagram showing a schematic configuration of an image display system 10 according to the present embodiment. The image display system 10 is mounted on a vehicle such as an automobile, and has a back monitor function for displaying an image showing a state behind the vehicle, and a navigation function for guiding a route of the vehicle.

  The image display system 10 includes an in-vehicle camera 2 provided behind the vehicle and a display device 3 provided in the passenger compartment. When the back monitor function is validated, a captured image showing the rear of the vehicle acquired by the in-vehicle camera 2 is displayed on the display device 3. On the other hand, when the navigation function is validated, various information such as a route and a navigation image that is a non-photographed image showing a map around the vehicle are displayed on the display device 3.

  The image display system 10 includes an image processing device 4 used for a back monitor function and a navigation unit 5 used for a navigation function. The image processing device 4 adjusts the captured image acquired by the in-vehicle camera 2 to be suitable for display, and outputs the adjusted captured image to the display device 3 for display. On the other hand, the navigation unit 5 acquires the current position of the vehicle and outputs and displays a navigation image including a map around the current position on the display device 3.

  The image display system 10 further includes an operation unit 8 that receives an operation from a user and a system control unit 1 that controls the entire system. The system control unit 1 receives a user instruction via the operation unit 8 and comprehensively controls the entire image display system 10 so as to operate according to the user instruction.

  Further, the system control unit 1 receives a vehicle shift position ("P (parking)", "D (forward)", "N (neutral)", "R (reverse)", etc.)) from a shift sensor 9 provided in the vehicle. Can be received. The system control unit 1 switches the display mode of the display device 3 according to the shift position.

  As shown in FIG. 2, the display mode of the display device 3 includes a navigation mode M2 and a back monitor mode M1. In the navigation mode M2, the navigation function is validated under the control of the system control unit 1, and a navigation image NP indicating a map and various types of information is displayed on the display device 3. On the other hand, in the back monitor mode M1, the back monitor function is validated by the control of the system control unit 1, and the captured image SP indicating the state behind the vehicle is displayed on the display device 3.

  The system control unit 1 sets the display mode of the display device 3 to the back monitor mode M1 when the shift position is “R (reverse)”, and displays the display mode of the display device 3 when the shift position is other than “R (reverse)”. Is set to the navigation mode M2. Therefore, when the user changes the shift position to “R (reverse)” in order to move the vehicle backward, the user can check the state behind the vehicle in substantially real time.

<1-2. Configuration of Image Processing Device>
Next, the configuration of the image processing apparatus 4 will be described. FIG. 3 is a diagram showing a detailed configuration of the image processing apparatus 4. The image processing apparatus 4 includes an image acquisition unit 41, a memory control unit 42, an image processing unit 43, an image output unit 44, a frame memory 45, and a mode determination unit 49.

  The image acquisition unit 41 acquires captured images from the in-vehicle camera 2 at a predetermined cycle. The image acquisition unit 41 converts an analog captured image acquired from the in-vehicle camera 2 into a digital captured image (A / D conversion). Thereby, the image acquisition part 41 outputs the video signal which contains a digital picked-up image (frame) with a predetermined period.

  The memory control unit 42 uses the frame memory 45 to adjust the synchronization timing of the video signal so as to match the synchronization timing of the display device 3.

  The image processing unit 43 performs predetermined image processing on the captured image included in the video signal adjusted by the memory control unit 42, and corrects the brightness and contrast of the captured image. The image processing unit 43 can also superimpose character information to be notified to the user on the captured image.

  The image output unit 44 outputs a video signal including the captured image (frame) processed by the image processing unit 43 to the display device 3. As a result, a captured image showing the state behind the vehicle is displayed on the display device 3.

  The mode determination unit 49 determines whether the display mode of the display device 3 is the navigation mode M2 or the back monitor mode M1 based on the signal from the system control unit 1.

  The frame memory 45 is a memory capable of storing a plurality of captured images (frames). The frame memory 45 includes four banks B1 to B4, which are a first bank B1, a second bank B2, a third bank B3, and a fourth bank B4. These four banks B1 to B4 are each a part of the storage area of the frame memory 45, and these are set in different parts. Each of the four banks B1 to B4 has a storage capacity capable of storing one photographed image (frame).

  The memory control unit 42 selects one of these four banks B1 to B4 as a writing bank, and writes a photographed image in this writing bank. The memory control unit 42 can select another one of the four banks B1 to B4 as a reading bank and read out the captured image from the reading bank in parallel with the writing of the captured image. is there.

  In order to write and read such a captured image, the memory control unit 42 includes an image writing unit 61, a writing bank selection unit 64, an image reading unit 62, and a reading bank selection unit 65.

  The image writing unit 61 periodically writes captured images (frames) included in the video signal output from the image acquisition unit 41 in the frame memory 45. The write bank to which the image writing unit 61 is to write the captured image is selected from the four banks B1 to B4 by the write bank selection unit 64.

  The writing bank selection unit 64 changes the bank to be written each time the image writing unit 61 writes one captured image (frame). Specifically, the write bank selection unit 64 selects a write target bank in the order of the first bank B1, the second bank B2, the third bank B3, and the fourth bank B4. Further, the write bank selection unit 64 selects the first bank B1 as the write target bank after the fourth bank B4. As a result, the image writing unit 61 sequentially writes captured images (frames) included in the video signal in time sequence into the four banks B1 to B4.

  The image reading unit 62 periodically reads the captured image stored in the frame memory 45 from the frame memory 45. The read bank from which the image reading unit 62 reads the captured image is selected from the four banks B1 to B4 by the read bank selection unit 65.

  The read bank selection unit 65 changes the read bank each time the image reading unit 62 reads one captured image (frame). When the read bank is changed, the read bank selection unit 65 selects a bank different from the write bank at that time among the four banks B1 to B4 as the read bank.

  The memory control unit 42 further has an inspection function for inspecting whether there is an abnormality in the frame memory 45. For such an inspection function, the memory control unit 42 includes a memory inspection unit 63 and an inspected bank selection unit 66.

  The memory inspection unit 63 inspects whether there is an abnormality in the frame memory 45 using the inspection data TD whose contents are determined in advance. Specifically, the memory inspection unit 63 reads the inspection data TD from a predetermined register and writes the inspection data TD to the bank to be inspected in the frame memory 45. Then, the memory inspection unit 63 reads the written inspection data from the bank to be inspected, and detects an abnormality in the frame memory 45 based on whether or not the read inspection data is the same as the original inspection data TD. That is, the memory inspection unit 63 determines that the frame memory 45 is abnormal when the read inspection data is different from the original inspection data TD. Thereby, the memory inspection unit 63 can inspect whether or not an image is correctly recorded in the frame memory 45.

  The bank to be inspected by the memory inspection unit 63 is selected from the four banks B1 to B4 by the bank to be inspected selection unit 66. The bank selection unit 66 selects a bank different from the write bank among the banks B1 to B4 as the bank to be tested in synchronization with the selection of the write bank by the write bank selection unit 64.

  Further, the memory inspection unit 63 includes an abnormality handling unit 67 for notifying the user of the occurrence of abnormality. When the memory inspection unit 63 detects an abnormality in the frame memory 45, the abnormality handling unit 67 outputs a predetermined signal to the image processing unit 43.

<1-3. Processing of Image Processing Device>
Next, processing of the image processing apparatus 4 will be described. As described above, the display mode of the display device 3 includes the navigation mode M2 and the back monitor mode M1. The processing of the image processing device 4 is executed not only in the back monitor mode M1 but also in the navigation mode M2. However, the processing contents of the image processing device 4 are different between the back monitor mode M1 and the navigation mode M2.

  The writing of the captured image to the frame memory 45 by the image writing unit 61 is executed in both the navigation mode M2 and the back monitor mode M1. This is because when the navigation mode M2 is switched to the back monitor mode M1, the captured image is displayed on the display device 3 immediately after the switching. Thereby, when the vehicle is moved backward, the user can quickly confirm the state behind the vehicle photographed by the in-vehicle camera 2.

  Further, the readout of the captured image from the frame memory 45 by the image readout unit 62 is executed only in the back monitor mode M1. On the other hand, the inspection of the frame memory 45 by the memory inspection unit 63 is executed only in the navigation mode M2.

  FIG. 4 is a diagram showing a flow of processing of the image processing apparatus 4. In the image processing apparatus 4, the operation shown in FIG. 4 is repeatedly executed at a predetermined cycle.

  First, the mode determination unit 49 determines the display mode of the display device 3. The mode determination unit 49 determines whether the display mode is the navigation mode M2 or the back monitor mode M1 based on the signal from the system control unit 1 (step S11). The determination result determined by the mode determination unit 49 is input to another processing unit of the image processing device 4 such as the memory control unit 42. Thereafter, when the display mode is the back monitor mode M1, the processes of steps S12 to S16 are performed, and when the display mode is the navigation mode M2, the processes of steps S21 to S25 are performed.

  When the display mode is the back monitor mode M1, first, the image acquisition unit 41 acquires a captured image from the in-vehicle camera 2, and converts the acquired analog captured image into a digital captured image (step S12).

  Next, the image writing unit 61 writes the captured image (frame) in the writing bank of the frame memory 45. The write bank selection unit 64 selects a write bank according to a predetermined order from among the four banks B1 to B4 at the start of writing by the image writing unit 61 (step S13).

  In parallel with the writing of the captured image, the image reading unit 62 reads the captured image (frame) from the reading bank of the frame memory 45. The read bank selection unit 65 selects a read bank from the four banks B1 to B4 at the start of reading by the image reading unit 62 (step S14).

  Read bank selection unit 65 selects a bank different from the write bank as a read bank. For example, the read bank selection unit 65 selects, as the read bank, a bank selected as a write bank in the previous process (ie, a bank in which writing of a captured image has been completed most recently) from among the four banks B1 to B4. . Therefore, for example, when the write bank is the first bank B1, the read bank is the fourth bank B4, and when the write bank is the second bank B2, the read bank is the first bank B1. This avoids contention between the write bank and the read bank.

  Next, the image processing unit 43 performs predetermined image processing on the captured image read by the image reading unit 62. Thus, the captured image is corrected so as to have brightness and contrast suitable for display on the display device 3 (step S15). Then, the image output unit 44 outputs the corrected captured image to the display device 3. Thereby, the picked-up image which shows the mode behind the vehicle is displayed on the display apparatus 3 (step S16).

  On the other hand, also when the display mode is the navigation mode M2, first, the image acquisition unit 41 acquires a captured image from the in-vehicle camera 2, and converts the acquired analog captured image into a digital captured image (step S21). Next, the image writing unit 61 writes the captured image (frame) in the writing bank of the frame memory 45. The writing bank selection unit 64 selects a writing bank according to a predetermined order from the four banks B1 to B4 at the time of starting writing by the image writing unit 61 (step S22).

  In parallel with the writing of the captured image, the memory inspection unit 63 inspects the frame memory 45. The bank to be inspected selecting unit 66 selects a bank to be inspected from the four banks B1 to B4 at the start of the inspection by the memory inspecting unit 63 (step S23).

  The bank to be inspected selecting unit 66 selects a bank different from the write bank as the bank to be inspected. For example, the bank to be inspected selecting unit 66 selects, as the bank to be inspected, of the four banks B1 to B4, the bank that has been selected as the writing bank first (that is, the bank in which the oldest photographed image is recorded). To do. Therefore, for example, when the write bank is the first bank B1, the bank to be tested is the second bank B2, and when the write bank is the second bank B2, the bank to be tested is the third bank B3. This avoids contention between the write bank and the bank to be inspected.

  The writing to the writing bank by the image writing unit 61 and the inspection of the bank to be inspected by the memory inspection unit 63 are executed in synchronization. In other words, the cycle in which the image writing unit 61 writes the captured image in one bank coincides with the cycle in which the memory inspection unit 63 inspects one bank.

  The image writing unit 61 has a line buffer, and writes the captured image to the writing bank in units of lines. When the image writing unit 61 writes one line to the writing bank, the memory inspection unit 63 inspects the storage area of the bank to be inspected corresponding to the one line.

  FIG. 5 is a timing chart for explaining the write timing by the image writing unit 61 and the test timing by the memory test unit 63. The horizontal direction in FIG. 5 indicates time, and T11 to T19 in the figure indicate time points, respectively.

  The image writing unit 61 repeats accumulation of one line of the captured image in the line buffer at a predetermined period PE. Then, when the accumulation of one line is completed in one period PE, the image writing unit 61 writes the line to the writing bank in the next period PE. For example, when the line L1 is accumulated in the line buffer at time points T11 to T13, the image writing unit 61 writes the line L1 to the write bank from time point T13.

  The frequency of the memory clock (for example, 100 MHz) of the frame memory 45 is approximately three times the frequency of the dot clock (for example, 31.5 MHz) of the video signal including the captured image. The image writing unit 61 can write one dot (pixel) of a captured image for each memory clock. Therefore, the image writing unit 61 can write one line to the writing bank in about 1/3 time before the cycle PE.

  For this reason, the time of about 2/3 after the period PE is a non-access time during which the image writing unit 61 does not access the frame memory 45. The memory inspection unit 63 inspects the inspected bank during the non-access time of the image writing unit 61.

  For example, the image writing unit 61 executes the writing of the line L1 to the writing bank at time points T13 to T14. For this reason, the memory inspection unit 63 performs the inspection of the storage area corresponding to the line L1 in the bank to be inspected at the time T14 to T15 which is the non-access time of the image writing unit 61.

  The memory inspection unit 63 writes the inspection data to the storage area corresponding to one line and reads the inspection data during such non-access time. Then, the storage area is inspected by comparing the written inspection data with the read inspection data. The memory inspection unit 63 repeats the inspection for each storage area corresponding to one line in accordance with the writing of one line of the image writing unit 61, thereby inspecting the entire storage area of the bank to be inspected. Execute.

  Returning to FIG. 4, when an abnormality of the frame memory 45 is detected by the inspection of the memory inspection unit 63 (Yes in Step S <b> 24), the abnormality handling unit 67 outputs a predetermined signal and outputs the image processing unit 43. Is notified that an abnormality has occurred (step S25). Upon receiving this signal, the image processing unit 43 superimposes character information indicating the occurrence of an abnormality in the frame memory 45 on the captured image. Thereby, in back monitor mode M1, the picked-up image containing this character information is displayed on the display apparatus 3, and it alert | reports generation | occurrence | production of abnormality to the user who visually recognizes the display apparatus 3. FIG.

  As described above, in the image display system 10, the display mode of the display device 3 includes the back monitor mode M1 that displays a captured image and the navigation mode M2 that displays a navigation image that is a non-captured image other than the captured image. . The image writing unit 61 of the image processing device 4 periodically writes a captured image in a writing bank selected from the four banks B1 to B4 in both the back monitor mode M1 and the navigation mode M2. In addition, the image reading unit 62 of the image processing apparatus 4 periodically reads captured images from a reading bank different from the writing bank only in the back monitor mode M1. On the other hand, the memory inspection unit 63 of the image processing apparatus 4 inspects a bank to be inspected that is different from the writing bank only in the navigation mode M2. Since the memory inspection unit 63 inspects the bank to be inspected in the navigation mode M2 in which the captured image is not read out, the bank to be inspected can be selected without considering the reading bank. Therefore, the frame memory 45 can be inspected while easily avoiding bank conflicts.

  When the memory inspection unit 63 detects an abnormality in the bank to be inspected, the abnormality handling unit 67 outputs a predetermined signal and outputs it to the image processing unit 43 to notify the user of the occurrence of the abnormality. For this reason, when an abnormality occurs in the frame memory 45, the user can recognize that a captured image showing a state around the vehicle cannot be normally displayed. Therefore, it is possible to prevent the user from making an erroneous determination based on a defective captured image and performing inappropriate driving.

<2. Second Embodiment>
Next, a second embodiment will be described. Since the configuration and processing of the image display system 10 of the second embodiment are substantially the same as those of the first embodiment, the following description will be focused on differences from the first embodiment.

  FIG. 6 is a diagram illustrating a detailed configuration of the image processing apparatus 4 according to the second embodiment. As shown in the figure, in the second embodiment, the frame memory 45 further includes a spare bank B5 serving as a spare for the four banks B1 to B4 in addition to the four banks B1 to B4. Also in the image processing apparatus 4 of the second embodiment, usually four banks B1 to B4 are used. However, if an abnormality occurs in any of the four banks B1 to B4, the image writing unit 61 and the image reading unit 62 use the spare bank B5 instead of the bank in which the abnormality has occurred. As a result, even if an abnormality occurs in any of the four banks B1 to B4, a normal captured image can be displayed on the display device 3.

  The abnormality handling unit 67 of the present embodiment, when the memory inspection unit 63 detects an abnormality in the frame memory 45, sends a signal for specifying a bank in which an abnormality has occurred to the write bank selection unit 64 and the read bank selection unit 65. And both. The write bank selection unit 64 and the read bank selection unit 65 that have received this signal select the spare bank B5 in place of the bank in which the abnormality has occurred.

  FIG. 7 is a diagram illustrating a processing flow of the image processing apparatus 4 according to the second embodiment. First, the mode determination unit 49 determines the display mode of the display device 3 (step S31). Thereafter, when the display mode is the back monitor mode M1, the processes of steps S32 to S37 are performed, and when the display mode is the navigation mode M2, the processes of steps S41 to S45 are performed.

  When the display mode is the back monitor mode M1, the processing in steps S32 to S37 is obtained by adding step S35 for inspecting the spare bank B5 to the processing in steps S12 to S16 of the first embodiment shown in FIG. ing.

  That is, first, the image acquisition unit 41 acquires a captured image from the in-vehicle camera 2 (step S32). Next, the image writing unit 61 writes the captured image in the writing bank of the frame memory 45 (step S33). In parallel with this, the image reading unit 62 reads a photographed image from the reading bank of the frame memory 45 (step S34).

  In parallel with the writing of the captured image (step S33) and the reading of the captured image (step S34), the memory inspection unit 63 performs the inspection of the spare bank B5. Even in the back monitor mode M1, the spare bank B5 is not used until an abnormality occurs. Therefore, it is possible to execute the inspection of the spare bank B5 without causing a problem of competition between banks.

  Next, the image processing unit 43 performs predetermined image processing on the captured image read by the image reading unit 62 (step S36), and the image output unit 23 outputs the corrected captured image to the display device 3. (Step S37).

  Further, the processing in steps S41 to S45 when the display mode is the back monitor mode M1 is substantially the same as the processing in steps S21 to S25 of the first embodiment shown in FIG. . Specifically, the processing contents (step S45) of the abnormality handling unit 67 when the abnormality of the frame memory 45 is detected are different from those of the first embodiment (step S25).

  That is, first, the image acquisition unit 41 acquires a captured image from the in-vehicle camera 2 (step S41). Next, the image writing unit 61 writes the photographed image in the writing bank of the frame memory 45 (step S42). In parallel with this, the memory inspection unit 63 inspects the bank to be inspected of the frame memory 45 (step S43).

  If an abnormality of the frame memory 45 is detected by the inspection of the memory inspection unit 63 (Yes in step S44), the abnormality handling unit 67 applies both to the write bank selection unit 64 and the read bank selection unit 65. Then, a signal for specifying the bank to be inspected in which an abnormality has occurred is transmitted (step S45). When receiving this signal, the write bank selection unit 64 and the read bank selection unit 65 select the spare bank B5 in place of the bank in which the abnormality has occurred. Accordingly, in the subsequent processing, the spare bank B5 is used instead of the bank in which the abnormality has occurred.

  In addition, after using the reserve bank B5 in this way, the same processing as in the first embodiment may be executed. Also, even if an abnormality in the spare bank B5 is detected in step S35 before detecting any abnormality in the four banks B1 to B4, the same processing as in the first embodiment is executed thereafter. That's fine.

  As described above, the image display system 10 according to the second embodiment further includes the spare bank B5 in addition to the four banks B1 to B4, and the memory inspection unit 63 detects an abnormality in the bank to be inspected. In this case, the spare bank B5 is used instead of the bank to be inspected. Therefore, even when an abnormality occurs in the frame memory 45, a normal captured image can be displayed on the display device 3 by using the spare bank B5.

  In addition, since the spare bank B5 is inspected in the back monitor mode M1, the frame memory 45 can be inspected outside the navigation mode M2, and the frame memory 45 can be inspected efficiently.

<3. Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible. Below, such a modification is demonstrated. All forms including those described in the above embodiment and those described below can be combined as appropriate.

  In the above embodiment, the display mode of the display device 3 is switched according to the shift position. However, the display mode may be switched depending on other conditions. For example, the display mode may be switched in response to a user instruction via the operation unit 8, or the display mode may be switched according to the speed of the vehicle.

  Moreover, in the said embodiment, although the vehicle-mounted camera 2 was taken as a thing image | photographing the back of a vehicle, you may image | photograph the front and the side of a vehicle. Alternatively, a plurality of in-vehicle cameras may be provided in the vehicle, and the image display system may generate and display a composite image viewed from a virtual viewpoint by combining captured images obtained by the plurality of in-vehicle cameras.

  In the above embodiment, even after the abnormality of the frame memory 45 is detected, the captured image is displayed on the display device 3 in the back monitor mode M1. On the other hand, when an abnormality is detected, in the back monitor mode M1, a non-photographed image in which the entire area is the same color (for example, black) is displayed on the display device 3, and a defective photographed image is not displayed. May be. In addition, when an abnormality is detected, only non-photographed images having the same color in all areas may be displayed on the display device 3 without superimposing character information indicating the occurrence of the abnormality.

  In the above-described embodiment, the image display system 10 mounted on the vehicle has been specifically described. However, an image display system that displays a captured image obtained by a monitoring camera arranged in a specific place on a display device, or the like. Even in an image display system that is not mounted on a vehicle, the technology described above can be suitably applied.

2 In-vehicle camera 3 Display device 4 Image processing device 45 Frame memory 49 Mode determination unit 61 Image writing unit 62 Image reading unit 63 Memory inspection unit 67 Abnormality handling unit M1 Back monitor mode M2 Navigation mode

Claims (7)

An image processing device for processing an image to be displayed on a display device,
Acquisition means for periodically acquiring captured images obtained by the camera;
A memory having a plurality of banks;
Determining means for determining whether a display mode of the display device is a first mode for displaying the captured image or a second mode for displaying a non-captured image other than the captured image;
In both the first and second modes, writing means for periodically writing the captured image acquired by the acquisition means to a writing bank selected from the plurality of banks;
Reading means for periodically reading the photographed image from a reading bank different from the writing bank of the plurality of banks in the first mode;
In the second mode, inspection means for inspecting a bank to be inspected that is different from the write bank among the plurality of banks;
An image processing apparatus comprising: The image processing apparatus according to claim 1.
Informing means for informing the user of the occurrence of an abnormality when the inspection means detects an abnormality in the bank to be inspected,
An image processing apparatus comprising: The image processing apparatus according to claim 2,
The image processing apparatus according to claim 1, wherein the camera is an in-vehicle camera that captures a periphery of a vehicle. The image processing apparatus according to claim 1.
The memory is a spare bank serving as a spare for the plurality of banks;
Further comprising
The writing unit and the reading unit use the spare bank instead of the bank to be inspected when the inspecting unit detects an abnormality in the bank to be inspected. The image processing apparatus according to claim 4.
The image processing apparatus, wherein the inspection unit inspects the spare bank in the first mode. An image display system for displaying an image,
An image processing device according to any one of claims 1 to 5,
A display device for displaying a photographed image processed by the image processing device;
An image display system comprising: An image processing method for processing an image to be displayed on a display device,
(A) periodically obtaining captured images obtained by a camera;
(B) determining whether the display mode of the display device is a first mode for displaying the captured image or a second mode for displaying a non-captured image other than the captured image;
(C) in both the first and second modes, periodically writing the captured image acquired in the step (a) into a write bank selected from a plurality of banks included in the memory;
(D) in the first mode, periodically reading the photographed image from a read bank different from the write bank among the plurality of banks;
(E) in the second mode, inspecting a bank to be inspected that is different from the write bank among the plurality of banks;
An image processing method comprising:

Images