Control Systems and Electronic Equipment

Abstract

To provide a control system and the like that, regardless of whether an error occurs in a step of error detection in image data or a step of communication of the image data, take measures according to the error.SOLUTION: A control system 400 includes: an image processing circuit 115; a first error detection circuit 170 that performs first error detection in second image data; a first error code value generation circuit 180 that generates a first error code value from the second image data; a transmission interface circuit 140; a reception interface circuit 210; a second error code value generation circuit 280 that generates a second error code value from the second image data; a second error detection circuit 370 that performs second error detection based on the first error code value and the second error code value; and a control circuit 310 that outputs a control signal when an error is detected in at least either one of the first error detection or the second error detection.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control system, an electronic device, and the like. [Background technology]

[0002] Patent Document 1 discloses a head-up display device that displays an image in a display area visible through the windshield from the driver's seat of a vehicle. This head-up display device has a vehicle information acquisition unit that acquires vehicle information detected by the vehicle, a control circuit that controls the display of the image, and an image display device that generates the image. The control circuit acquires device information that is information used to determine whether or not there is an apparatus abnormality, and performs a display content change process that changes the displayed image content if it determines that there is an apparatus abnormality. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 058645 Summary of the Invention [Problem to be solved by the invention]

[0004] In a display device control system, multiple circuit devices are connected in series via communication, and the multiple circuit devices sequentially perform image processing, display control, etc. In this case, even if an image data anomaly detection is performed in a circuit device and it is confirmed that there is no anomaly in the image data, an image data error may occur in a subsequent circuit device or during communication. When such an error occurs, there is a problem in that no action is taken in response to the anomaly detection, even though the result of the anomaly detection is not compensated for until the final display stage.

[0005] In the above-mentioned Patent Document 1, when a control circuit determines that there is an abnormality in a device based on device information acquired from each device in the vehicle, it changes the image display content. However, there is no disclosure of how to detect an abnormality in the image data after the change. Furthermore, there is no mention of what to do if an error in the image data occurs within the downstream circuit device or during communication. [Means for solving the problem]

[0006] One aspect of the present disclosure relates to a control system for controlling a head-up display, the control system including: an image processing circuit that maps input first image data to second image data to be projected onto a projection surface of the head-up display; a first error detection circuit that performs first error detection on the second image data; a first error code value generation circuit that generates a first error code value from the second image data; a transmission interface circuit that transmits the second image data; a receiving interface circuit that receives the second image data transmitted by the transmission interface circuit; a second error code value generation circuit that generates a second error code value from the second image data received by the receiving interface circuit; a second error detection circuit that performs second error detection on the second image data received by the receiving interface circuit based on the first error code value and the second error code value; and a control circuit that outputs a control signal to turn off projection of light onto the projection surface when an error is detected in at least one of the first error detection or the second error detection.

[0007] Another aspect of the present disclosure relates to an electronic device including the above-described control system and the head-up display. [Brief explanation of the drawings]

[0008] [Figure 1] An example of a head-up display. [Figure 2] An example of the configuration of electronic devices. [Figure 3] First configuration example of a control system. [Figure 4] 3 is a processing flowchart of the control system. [Figure 5] An example of a modified head-up display configuration. [Figure 6] Second configuration example of a control system. [Figure 7] Third example of control system configuration. [Figure 8] 10 is a configuration example of an image processing device when performing first error detection using inverse mapping processing. [Figure 9] 10 shows an example of the configuration of an image processing device and a processing device when the image processing device detects a processing error in distortion correction. [Figure 10] A detailed configuration example of the image processing circuit and the third error detection circuit. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present disclosure will be described in detail below. Note that the embodiments described below do not unduly limit the scope of the claims, and not all of the configurations described in the embodiments are necessarily essential components.

[0010] 1. Deterioration of head-up display visibility due to image abnormalities Figure 1 shows an example of a head-up display. Hereinafter, head-up display will be abbreviated to HUD. Here, we will explain an example in which the HUD is installed on a moving object such as an automobile, airplane, or ship, and presents information to a user on board the moving object. Note that the use of the HUD is not limited to moving objects, and it may be anything that presents information superimposed on the user's field of vision.

[0011] As shown in the upper part of Figure 1, a user on board a moving vehicle can see the outside scenery through the windscreen. Hereinafter, this will be referred to as the background. The HUD screen 10 is set within the background, and the screen 10 is transparent to the background except for the information display portion. In the example of Figure 1, the AR display 20 that follows the leading vehicle 50 is the information display portion, and the portion other than the AR display 20 is transparent to the background. This allows the user to see the information displayed on the HUD along with the background.

[0012] Typically, the AR display 20 occupies a small proportion of the screen 10 of the HUD so that the user can see the background that is visible through the screen 10. Furthermore, since the display position of the AR display 20 is controlled to follow the vehicle in front 50, the AR display 20 normally does not overlap the vehicle in front 50. However, as shown in the lower part of Figure 1, if an abnormality occurs in image processing, the abnormal display may reduce the visibility of the background. The lower part of Figure 1 shows an example in which an abnormally enlarged AR display 30 covers the vehicle in front 50, making it impossible for the user to see the vehicle in front 50. Note that abnormal conditions that reduce visibility are not limited to the lower part of Figure 1, and may include any condition in which a display that covers a relatively large proportion of the screen 10 obscures the background, or any condition in which a high-brightness image is displayed on the screen 10 making it difficult to see the background.

[0013] 2. Electronic equipment and control systems 2 shows an example of the configuration of the electronic device 600 according to this embodiment. The electronic device 600 is a HUD system, and includes a control system 400 and a head-up display 500.

[0014] The control system 400 is a system that controls the head-up display 500, and specifically, controls the display of the head-up display 500 by transmitting image data IMB and timing control signals to the head-up display 500.

[0015] The head-up display 500 projects an image onto a projection surface based on image data IMB and a timing control signal, thereby displaying a virtual image in the field of view of a user viewing the projection surface. The projection surface may be a windscreen of a vehicle equipped with a HUD system, or a screen provided specifically for the HUD system. The head-up display 500 includes a display driver 510, a backlight controller 520, a light source 530, a display panel 540, and an optical system 550.

[0016] The display driver 510 drives the display panel 540 based on the image data IMB and timing control signals from the control system 400, causing the display panel 540 to display an image. In the example of FIG. 2, the display panel 540 is a liquid crystal display panel. The backlight controller 520 controls the on / off and output light intensity of the light source 530. The light source 530 emits light to the display panel 540. The optical system 550 projects the light that has passed through the display panel 540 onto a projection surface. As a result, the image displayed on the display panel 540 is projected onto the projection surface.

[0017] The head-up display 500 is not limited to that shown in FIG. 2. For example, the display panel 540 may be a panel using a self-luminous element such as an OLED. OLED stands for Organic Light Emitting Diode. In this case, the light source 530 and the backlight controller 520 are omitted, and the optical system 550 projects the light emitted by the display panel 540 onto the projection surface. Alternatively, the display driver 510 may be included in the control system 400. In this case, the display driver 510 and the display controller 200 (described later) may be configured as an integrated circuit device.

[0018] 3 shows a first example of the configuration of a control system 400 according to this embodiment. The control system 400 includes an image processing device 100, a display controller 200, and a processing device 300. Each of the image processing device 100, the display controller 200, and the processing device 300 is configured, for example, by an integrated circuit device in which a plurality of circuit elements are integrated on a semiconductor substrate. As described above, the display controller 200 may further include the function of the display driver 510.

[0019] The image processing device 100 performs distortion correction on the first image data IMA and outputs the distortion-corrected second image data IMB. The distortion correction is a correction that cancels or reduces image distortion caused by distortion of the projection surface of the head-up display or image distortion caused by the optical system. The image processing device 100 includes a receiving interface circuit 110, an image processing circuit 115, a transmitting interface circuit 140, a first error detection circuit 170, and a first error code value generation circuit 180.

[0020] The receiving interface circuit 110 receives first image data IMA from an external device such as the processing device 300. The receiving interface circuit 110 may be a receiving circuit for various communication interfaces, for example, LVDS, DVI, DisplayPort, GMSL, or GVIF. LVDS stands for Low Voltage Differential Signaling, DVI stands for Digital Visual Interface, GMSL stands for Gigabit Multimedia Serial Link, and GVIF stands for Gigabit Video Interface.

[0021] The image processing circuit 115 maps the first image data IMA to second image data IMB for projection onto the projection surface of the head-up display 500. This mapping process corresponds to the distortion correction described above. The mapping process is also called warping. The image processing circuit 115 may be either a reverse warp engine or a forward warp engine. Reverse warping is a warping process that moves pixel positions on the second image data IMB to corresponding reference coordinates and obtains pixel data of the second image data IMB from pixel data of the first image data IMA at those reference coordinates. Forward warping is a warping process that moves each pixel data of the first image data IMA to corresponding destination coordinates to obtain pixel data of the second image data IMB at those destination coordinates.

[0022] The transmission interface circuit 140 transmits the second image data IMB to the display controller 200. The transmission interface circuit 140 may be a transmission circuit of various communication interfaces, for example, a transmission circuit of LVDS, DVI, DisplayPort, GMSL, or GVIF.

[0023] The first error detection circuit 170 performs first error detection on the second image data IMB output by the image processing circuit 115 and outputs the result as a first error detection signal ER1. In the first configuration example, the first error detection is glare error detection. Specifically, the first error detection circuit 170 obtains a glare index value, which is an index value indicating the glare of the head-up display, from the second image data IMB. The first error detection circuit 170 compares the glare index value with a threshold value, and determines that a glare error has occurred if the glare index value is greater than the threshold value.

[0024] The glare index value is an index value that indicates the glare of the head-up display. Specifically, the glare index value indicates the degree to which the visibility of the background is reduced by an image based on the second image data IMB when the image is displayed on the head-up display. That is, as described in FIG. 1, there are cases in which the image displayed on the head-up display obscures the background, or in which the glare of the image displayed on the head-up display makes it difficult to see the background, and the glare index value indicates the degree to which these cases occur.

[0025] The first error detection circuit 170 calculates the glare index value by integrating pixel values ​​included in the second image data IMB for one screen, i.e., one display frame. Specifically, if the glare index value is B, then B is calculated as follows: B = C1 × Rsum + C2 × Gsum + C3 × Bsum. Here, Rsum is the integrated value of red pixel values, Gsum is the integrated value of green pixel values, and Bsum is the integrated value of blue pixel values, and C1, C2, and C3 are coefficients. The coefficients C1, C2, and C3 are used to convert RGB pixel values ​​into YCrCb luminance values ​​Y, and are set appropriately depending on the color space used for the image data. However, the coefficients C1, C2, and C3 are not limited to these and may be any real numbers greater than 0. Alternatively, the first error detection circuit 170 may calculate the luminance value Y for each pixel and then integrate Y to calculate the glare index value B. In this case, Y = C1 × Rpx + C2 × Gpx + C3 × Bpx, and B = Ysum. Rpx, Gpx, and Bpx are the red, green, and blue pixel values ​​of one pixel. Ysum is the sum of the luminance values ​​Y.

[0026] The first error code value generation circuit 180 generates a first error code value CD1 from the second image data IMB output by the image processing circuit 115. The first error code value generation circuit 180 generates the first error code value CD1 from the second image data IMB for one frame, for example, for each frame. If no error is detected in the first error detection, the second image data IMB is guaranteed to be image data without any abnormalities by the first error detection. In other words, the first error code value CD1 is an error code value generated from the second image data IMB that is guaranteed to be without any abnormalities. The first error code value CD1 is, for example, a CRC code. CRC stands for Cyclic Redundancy Check. Alternatively, the first error code value CD1 may be a checksum, a Hamming code, or an ECC code. ECC stands for Error Correcting Code.

[0027] The display controller 200 performs display control of the head-up display 500. Specifically, the display controller 200 generates a timing control signal and transmits the timing control signal together with the received second image data IMB to the head-up display 500. The display controller 200 includes a receiving interface circuit 210, a timing generation circuit 220, a transmitting interface circuit 240, and a second error code value generation circuit 280.

[0028] The receiving interface circuit 210 receives the second image data IMB from the image processing device 100. The receiving interface circuit 210 may be a receiving circuit for various communication interfaces, and examples include a receiving circuit for LVDS, DVI, DisplayPort, GMSL, or GVIF.

[0029] The timing generation circuit 220 generates timing control signals that control the display timing of the head-up display 500. The timing control signals include, for example, a vertical synchronization signal, a horizontal synchronization signal, a dot clock signal, and a data enable signal.

[0030] The transmission interface circuit 240 transmits the second image data IMB and the timing control signal to the display driver 510 of the head-up display 500. The transmission interface circuit 240 may be a transmission circuit of various communication interfaces, examples of which include LVDS, DVI, DisplayPort, GMSL, and GVIF.

[0031] The second error code value generation circuit 280 generates a second error code value CD2 from the second image data IMB received by the receiving interface circuit 210. For example, for each frame, the second error code value generation circuit 280 generates the second error code value CD2 from the second image data IMB for that frame. The second error code value generation circuit 280 calculates the second error code value CD2 using the same calculation method as the first error code value generation circuit 180 uses to calculate the first error code value CD1. For example, if the first error code value CD1 is a CRC code, the second error code value CD2 is also a CRC code calculated by the same CRC calculation. Alternatively, if the first error code value CD1 is a checksum, a Hamming code, or an ECC code, the second error code value CD2 is also a checksum, a Hamming code, or an ECC code.

[0032] The processing device 300 is a processor that performs system control of the electronic device 600. The processor is a microcomputer, a CPU, or the like. CPU is an abbreviation for Central Processing Unit. Alternatively, the processing device 300 may be an FPGA, an ASIC, or the like. FPGA is an abbreviation for Field-Programmable Gate Array. ASIC is an abbreviation for Application Specific Integrated Circuit. The processing device 300 includes a second error detection circuit 370 and a control circuit 310.

[0033] The second error detection circuit 370 detects a communication error between the image processing device 100 and the display controller 200 by second error detection and outputs a second error detection signal ER2 as a result. Specifically, the second error detection circuit 370 compares the first error code value CD1 with the second error code value CD2. When the first error code value CD1 and the second error code value CD2 do not match, the second error detection circuit 370 outputs the second error detection signal ER2 indicating an error. When the first error code value CD1 and the second error code value CD2 match, the second error detection circuit 370 outputs the second error detection signal ER2 indicating no error.

[0034] The control circuit 310 outputs a control signal CNT based on the first error detection signal ER1 and the second error detection signal ER2. Specifically, when an error is detected in the first error detection, the second error detection, or both, the control circuit 310 outputs a control signal CNT that turns off the projection of light onto the projection surface of the HUD. In the first configuration example, when the above-mentioned error is detected, the control circuit 310 outputs a control signal CNT that turns off the light source 530 to the backlight controller 520. When the control signal CNT that turns off the light source 530 is input, the backlight controller 520 turns off the light source 530. This results in a state where no light is projected onto the projection surface, allowing the user to view the background through the projection surface.

[0035] 4 is a processing flowchart of the control system 400. In step S1, the image processing circuit 115 performs mapping processing to correct distortion of the first image data IMA.

[0036] In step S2, the first error detection circuit 170 performs a visibility check on the distortion-corrected second image data IMB by detecting a glare error. As described above, the visibility check means checking whether the visibility of the background is good through the head-up display when an image based on the second image data IMB is displayed. In step S3, the control circuit 310 performs processing according to the result of the visibility check. If the visibility check results in an error, in step S4, the control circuit 310 outputs a control signal CNT to turn off the light source 530. If there is no problem in the visibility check, the process proceeds to step S5.

[0037] In step S5, the first error code value generation circuit 180 calculates a CRC code from the second image data IMB output by the image processing circuit 115. In step S6, the transmission interface circuit 140 transmits the second image data IMB, and the reception interface circuit 210 receives the second image data IMB. In step S7, the second error code value generation circuit 280 calculates a CRC code from the second image data IMB received by the reception interface circuit 210.

[0038] In step S8, the second error detection circuit 370 compares the two CRC codes. In step S9, the control circuit 310 determines whether the two CRC codes match. This determination corresponds to a visibility check in the display controller 200. In other words, if the two CRC codes match, this means that the same image data as the second image data IMB that passed the visibility check in the image processing circuit 115 has been input to the display controller 200, and that there is no problem with the visibility of the second image data IMB in the display controller 200 either.

[0039] In step S9, if the CRC codes match, the control circuit 310 ends the process, and if the CRC codes do not match, in step S4, the control circuit 310 outputs a control signal CNT that turns off the light source 530.

[0040] 2 illustrates an example in which display panel 540 is a liquid crystal display panel and control circuit 310 outputs control signal CNT to turn off light source 530, but the configuration for turning off the projection of light onto the projection surface is not limited to this. "Turning off the projection of light onto the projection surface" means that any method is acceptable as long as it can ultimately achieve a state in which no light is projected onto the projection surface.

[0041] For example, Fig. 5 shows a modified configuration example of the head-up display 500. In Fig. 5, the control circuit 310 outputs a control signal CNT that stops the display driver 510 from driving the display panel 540. When the control signal CNT is input, the display driver 510 stops displaying an image based on the second image data IMB and sets the display panel 540 to a non-transmitting state. This results in a state where no light is projected onto the projection surface.

[0042] Alternatively, the display panel 540 may be a panel using self-luminous elements. In this case, the control circuit 310 outputs a control signal CNT that turns off the light emission of all pixels of the display panel 540. When the control signal CNT is input, the display panel 540 stops displaying an image based on the second image data IMB and sets all pixels to a non-light-emitting state. This results in a state where no light is projected onto the projection surface.

[0043] Alternatively, FIG. 6 shows a second configuration example of the control system 400. In FIG. 6, the image processing device 100 includes a second error detection circuit 370, a control circuit 310, and a mask circuit 190. When at least one of the first error detection circuit 170 and the second error detection circuit 370 detects an error, the control circuit 310 outputs a control signal CNT that masks the second image data IMB. When the control signal CNT is input, the mask circuit 190 masks the second image data IMB input to the transmission interface circuit 140. At this time, the mask circuit 190, for example, stops output of image data or outputs image data that displays a full black screen to the transmission interface circuit 140. This prevents light from being projected onto the projection surface. When neither the first error detection circuit 170 nor the second error detection circuit 370 detects an error, the mask circuit 190 outputs the second image data IMB as is to the transmission interface circuit 140.

[0044] Alternatively, FIG. 7 shows a third configuration example of the control system 400. In FIG. 7, the display controller 200 includes a second error detection circuit 370, a control circuit 310, and a mask circuit 290. When at least one of the first error detection circuit 170 and the second error detection circuit 370 detects an error, the control circuit 310 outputs a control signal CNT that masks the second image data IMB. When the control signal CNT is input, the mask circuit 290 masks the second image data IMB input to the transmission interface circuit 240. This prevents light from being projected onto the projection surface. When neither the first error detection circuit 170 nor the second error detection circuit 370 detects an error, the mask circuit 290 outputs the second image data IMB to the transmission interface circuit 240 as is.

[0045] In the above-described embodiment, the control system 400 includes an image processing circuit 115 that performs mapping processing on input first image data IMA to second image data IMB to be projected on the projection surface of the head-up display 500, a first error detection circuit 170 that performs first error detection on the second image data IMB, and a first error code value generation circuit 180 that generates a first error code value CD1 from the second image data IMB. The control system 400 also includes a transmission interface circuit 140 that transmits the second image data IMB, a reception interface circuit 210 that receives the second image data IMB transmitted by the transmission interface circuit 140, and a second error code value generation circuit 280 that generates a second error code value CD2 from the second image data IMB received by the reception interface circuit 210. The control system 400 includes a second error detection circuit 370 that performs second error detection on the second image data IMB received by the receiving interface circuit 210 based on the first error code value CD1 and the second error code value CD2, and a control circuit 310 that outputs a control signal CNT that turns off the projection of light onto the projection surface when an error is detected in at least one of the first error detection or the second error detection.

[0046] According to this embodiment, the first error detection circuit 170 performs first error detection on the second image data IMB, and then the transmission interface circuit 140 and the reception interface circuit 210 transmit and receive the second image data IMB. At this time, the second error detection circuit 270 performs second error detection based on the first error code value CD1 generated from the second image data IMB before transmission and the second error code value CD2 generated from the second image data IMB after reception. This ensures that the received second image data IMB is the same image data as the second image data IMB after the first error detection. For example, if a visibility check was performed during the first error detection to determine whether the background visibility was good when an image was displayed on a head-up display, visibility is also guaranteed for the received second image data IMB.

[0047] When an error is detected in at least one of the first error detection or the second error detection, the projection of light onto the projection surface is turned off, so that an image is not displayed based on the second image data IMB in which the error occurred, and no light is irradiated onto the projection surface, thereby allowing the user to view the background through the screen of the head-up display 500.

[0048] Note that the hardware configuration of the control system 400 shown in FIG. 3 is just an example, and the control system 400 may have any configuration as long as it includes the image processing circuit 115, the first error detection circuit 170, the first error code value generation circuit 180, the transmission interface circuit 140, the reception interface circuit 210, the second error code value generation circuit 280, the second error detection circuit 370, and the control circuit 310.

[0049] In this embodiment, the first error detection circuit 170 determines a glare index value, which is an index value indicating the glare of the head-up display 500, based on the second image data IMB, and performs first error detection based on the glare index value.

[0050] According to this embodiment, the first error detection circuit 170 performs first error detection based on the glare index value, thereby detecting a state in which the visibility of the background is reduced by an image based on the second image data IMB as a glare error. As a result, when no glare error is detected in the first error detection and the second error detection, it is guaranteed that there is no glare error in the second image data IMB received by the receiving interface circuit 210. Furthermore, when an error is detected in at least one of the first error detection or the second error detection, the projection of light onto the projection surface is turned off, and therefore the second image data IMB that is not guaranteed to be free of a glare error is not displayed on the head-up display 500.

[0051] In this embodiment, the control system 400 includes a first circuit device and a second circuit device. The first circuit device includes an image processing circuit 115, a first error detection circuit 170, a first error code value generation circuit 180, and a transmission interface circuit 140. The second circuit device includes a reception interface circuit 210 and a second error code value generation circuit 280.

[0052] According to this embodiment, it is guaranteed that the second image data IMB received by the second circuit device in the subsequent stage is the same image data IMB as the second image data IMB after the first error detection in the first circuit device in the preceding stage. As a result, even if the first circuit device performs the first error detection and a second circuit device is provided in the subsequent stage, the result of the first error detection can be substantially guaranteed in the second circuit device in the subsequent stage. Then, when it becomes impossible to guarantee that the second image data IMB is error-free in either the previous or subsequent stage, the projection of light onto the projection surface is turned off.

[0053] In FIG. 3, the image processing device 100 is the first circuit device and the display controller 200 is the second circuit device, but the first and second circuit devices are not limited to this. For example, the second circuit device may be a display driver. In this case, the first circuit device may be a display controller with a built-in distortion correction function, or the second circuit device may be a display driver with a built-in display controller function. Furthermore, the control system 400 may include a first circuit device that is the image processing device 100, a second circuit device that is the display controller 200, and a third circuit device that is a display driver. In this case, error detection equivalent to the second error detection may be performed on the second image data received by the third circuit device.

[0054] In this embodiment, the control circuit 310 outputs a control signal CNT that turns off the light source 530 of the head-up display 500.

[0055] According to this embodiment, when an error is detected in at least one of the first error detection and the second error detection, the light source 530 is turned off, and therefore an image is not displayed based on the second image data IMB in which the error has occurred.

[0056] As also described in FIG. 6, the control system 400 may include a mask circuit 190 that masks the second image data IMB before it is transmitted by the transmission interface circuit 140 based on the control signal CNT.

[0057] According to this embodiment, when an error is detected in at least one of the first error detection or the second error detection, the second image data IMB is masked before being transmitted by the transmission interface circuit 140, so that an image is not displayed using the second image data IMB in which an error has occurred.

[0058] As described in FIG. 7, the control system 400 may also include a mask circuit 290 that masks the second image data IMB received by the receiving interface circuit 210 based on the control signal CNT.

[0059] According to this embodiment, when an error is detected in at least one of the first error detection or the second error detection, the second image data IMB received by the receiving interface circuit 210 is masked, so that an image is not displayed based on the second image data IMB in which the error occurred.

[0060] 3. First error detection using reverse mapping Although Fig. 3 illustrates an example in which the first error detection is glare error detection, the first error detection is not limited to this. Fig. 8 illustrates an example of the configuration of the image processing device 100 when performing first error detection using inverse mapping processing. Note that components that have already been described are assigned the same reference numerals, and descriptions of those components will be omitted where appropriate.

[0061] In this configuration example, the first error detection circuit 170 detects errors in the second image data IMB by comparing the third image data IMC, which is obtained by performing an inverse mapping process on the second image data IMB, with the first image data IMA. The first error detection circuit 170 includes an inverse conversion circuit 171 and a comparison circuit 172.

[0062] The inverse conversion circuit 171 performs an inverse mapping process on the second image data IMB and outputs the processed third image data IMC. The inverse mapping process is the inverse conversion of the mapping process performed by the image processing circuit 115. That is, if the mapping process in the image processing circuit 115 and the inverse mapping process in the inverse conversion circuit 171 are performed normally, the third image data IMC and the first image data IMA will be identical. However, since interpolation processes and the like are performed in the mapping process or the inverse mapping process, the third image data IMC and the first image data IMA do not need to be completely identical. Specifically, it is sufficient that the third image data IMC and the first image data IMA are substantially identical to the extent that the content of the image indicated by the third image data IMC and the content of the image indicated by the first image data IMA are determined to be identical.

[0063] The comparison circuit 172 performs a comparison process between the first image data IMA and the third image data IMC and outputs a first error detection signal ER1 as a result. Specifically, the comparison circuit 172 obtains an index indicating the similarity between the first image data IMA and the third image data IMC. The index is a shape index or a visibility index, which will be described later. Alternatively, the index may be SSD (Sum of Squared Difference), SAD (Sum of Absolute Difference), NCC (Normalized Cross Correlation), or the like. The comparison circuit 172 detects errors in the second image data IMB by comparing the index with a threshold value. The threshold value indicates the degree of similarity between the first image data IMA and the third image data IMC that is acceptable.

[0064] A first calculation method for the shape index will be described. The comparison circuit 172 calculates the inter-image distance between the first image data IMA and the third image data IMC in color space. The color space is, for example, RGB or YCrCb. Specifically, the comparison circuit 172 calculates the square value of the distance between a pixel of the first image data IMA and a corresponding pixel of the third image data IMC in color space. The comparison circuit 172 integrates the square value within the image and regards the integrated value as the inter-image distance. In the first calculation method, the inter-image distance corresponds to the shape index.

[0065] Next, a second calculation method for the shape index will be described. The comparison circuit 172 performs edge extraction on the first image data IMA and the third image data IMC to obtain respective edge images. The comparison circuit 172 compares the edge image extracted from the first image data IMA with the edge image extracted from the third image data IMC. Specifically, the comparison circuit 172 extracts edges from the first image data IMA and the third image data IMC using a Sobel filter or the like, and obtains a correlation value between the edge image extracted from the first image data IMA and the edge image extracted from the third image data IMC. In the second calculation method, the correlation value of the edge image corresponds to the shape index.

[0066] Next, a method for calculating the visibility index will be described. The "visibility" in the visibility index refers to the visibility of displayed objects such as icons displayed on a head-up display, and is different from the visibility of the background described above. Here, the color space is YCrCb, but the color space may be RGB or the like. The comparison circuit 172 obtains a histogram from the Y channel of the first image data IMA. Similarly, the comparison circuit 172 obtains a histogram from the Cr channel and Cb channel of the first image data IMA, and obtains a histogram from the Y channel, Cr channel, and Cb channel of the third image data IMC.

[0067] The comparison circuit 172 performs a cross-correlation calculation on the histograms of the first image data IMA and the third image data IMC in the Y channel. The cross-correlation calculation is a calculation in which the two histograms are shifted by a delay to find a correlation value, and the correlation value is calculated while changing the delay. If the delay is changed and there is a point where the correlation value between the two histograms becomes high, a peak will appear at that delay. There may be multiple peaks. Similarly, the comparison circuit 172 performs a cross-correlation calculation on the histograms of the first image data IMA and the third image data IMC in the Cr channel and the Cb channel.

[0068] The comparison circuit 172 examines the delay values ​​at which peaks appear in the cross-correlation signals of all channels and finds the maximum delay value among those delay values. This maximum delay value corresponds to the visibility index. When the contrast between the color of an object, such as an icon, and the color of the background image is high, the maximum delay value increases, so the visibility index indicates the contrast between the color of the object and the color of the background image. Since the higher the color contrast, the higher the visibility, the higher the similarity is determined to be.

[0069] The image processing device 100 may perform both the error detection using the inverse mapping process and the glare error detection described with reference to FIG. 3 and the like on the second image data IMB.

[0070] In the above embodiment, the first error detection circuit 170 performs first error detection by converting the second image data IMB into the third image data IMC by performing an inverse mapping process of the mapping process, and comparing the first image data IMA with the third image data IMC.

[0071] If an abnormality occurs in the mapping process, and an image is displayed on the head-up display using the second image data IMB after the mapping process, the visibility of the background may be reduced. According to this embodiment, the first image data IMA is compared with the third image data IMC obtained by performing the inverse mapping process thereon to determine whether the mapping process from the first image data IMA to the second image data IMB is normal. As a result, when no error is detected in the first error detection and the second error detection, it is guaranteed that there is no mapping process error in the second image data IMB received by the receiving interface circuit 210. Furthermore, when an error is detected in at least one of the first error detection and the second error detection, the projection of light onto the projection surface is turned off, and therefore the second image data IMB, for which it is not guaranteed that there is no mapping process error, is not displayed on the head-up display 500.

[0072] 4. Third error detection 9 shows an example of the configuration of the image processing device 100 and the processing device 300 when the image processing device 100 detects a processing error in distortion correction. In this example, the image processing device 100 includes a third error detection circuit 150. Note that components that have already been described are given the same reference numerals, and descriptions of those components will be omitted where appropriate.

[0073] In this configuration example, the image processing device 100 includes a third error detection circuit 150. In the mapping process, the image processing circuit 115 outputs reference coordinates RCRD on the first image data IMA that correspond to pixel positions on the second image data IMB. The third error detection circuit 150 detects errors in the reference coordinates RCRD to detect processing errors in the distortion correction, and outputs a third error detection signal ER3 as the result.

[0074] The control circuit 310 outputs a control signal CNT based on the first error detection signal ER1, the second error detection signal ER2, and the third error detection signal ER3. Specifically, when an error is detected in the first error detection, the second error detection, the third error detection, or two or more of these error detections, the control circuit 310 outputs the control signal CNT to turn off the projection of light onto the projection surface of the HUD.

[0075] Although Figure 9 shows an example in which the control circuit 310 is included in the processing device 300, the control circuit 310 may be included in the image processing device 100 as shown in Figure 6, or in the display controller 200 as shown in Figure 7.

[0076] 10 shows a detailed configuration example of the image processing circuit 115 and the third error detection circuit 150. The image processing circuit 115 includes a memory circuit 120, an image conversion circuit 130, and a coordinate address conversion circuit 160. The third error detection circuit 150 includes an arithmetic circuit 151 and a comparison circuit 152.

[0077] The first image data IMA is stored in the memory circuit 120. The memory circuit 120 is a line buffer that stores image data for a predetermined number of lines, or a frame memory that stores image data for one frame.

[0078] The image conversion circuit 130 performs image conversion using coordinate conversion on the first image data IMA and outputs second image data IMB after the image conversion. Image conversion using coordinate conversion is image conversion that generates the second image data IMB by moving pixel data of the first image data IMA to pixel positions on the second image data IMB indicated by the coordinate conversion. Specifically, the image conversion circuit 130 generates the second image data IMB by performing distortion correction on the first image data IMA.

[0079] The image transformation circuit 130 corresponds to a reverse warp engine. The meaning of reverse warp is as described above. The image transformation circuit 130 outputs reference coordinates RCRD on the first image data IMA that correspond to pixel positions on the second image data IMB based on the correction parameters WP, which are warp parameters.

[0080] The coordinate address conversion circuit 160 converts the reference coordinate RCRD into a read address RADD of the storage circuit 120. The read address RADD is an address at which pixel data corresponding to the reference coordinate RCRD is stored.

[0081] The memory circuit 120 reads out the pixel data PXDT from the read address RADD and outputs it to the image conversion circuit 130. The image conversion circuit 130 composes the second image data IMB from the pixel data PXDT. As will be described later, multiple pixel data may be read for one reference coordinate RCRD, and the image conversion circuit 130 may obtain the pixel data of the second image data IMB by performing an interpolation process on the multiple pixel data.

[0082] The third error detection circuit 150 includes a calculation circuit 151 that calculates an error code value CDQ from the reference coordinates RCRD, and a comparison circuit 152 that compares the error code value CDQ with an expected value CDEX of the error code value.

[0083] For each frame, the calculation circuit 151 calculates one error code value CDQ from the reference coordinates RCRD for that frame. The error code value CDQ is, for example, a CRC code. CRC stands for Cyclic Redundancy Check. Alternatively, the error code value CDQ may be a checksum, a Hamming code, or an ECC code. ECC stands for Error Correcting Code.

[0084] The comparator circuit 152 outputs a third error detection signal ER3 indicating an error when the error code value CDQ and the expected value CDEX do not match, and outputs a third error detection signal ER3 indicating no error when the error code value CDQ and the expected value CDEX match. The expected value CDEX is associated with a correction parameter WP, and when the correction parameter WP is changed, the expected value CDEX is also changed accordingly. The correction parameter WP and the expected value CDEX are input to the image processing device 100 from an external device such as the processing device 300.

[0085] It should be noted that the third error detection circuit 150 only needs to perform error detection on the reference coordinates RCRD. That is, in FIG. 10, the third error detection circuit 150 detects an error on the reference coordinates RCRD, but this is not limiting. The third error detection circuit 150 may perform error detection on the reference coordinates RCRD by detecting an error in data generated based on the reference coordinates RCRD. For example, the third error detection circuit 150 may detect an error in the read address RADD output based on the reference coordinates RCRD. In this case, whether the reference coordinates RCRD are correct is checked by checking whether the read address RADD is correct.

[0086] In the above-described embodiment, the control system 400 includes a third error detection circuit 150. The image processing circuit 115 includes a memory circuit 120 that stores first image data IMA and an image conversion circuit 130 that maps the first image data IMA stored in the memory circuit 120 to second image data IMB. The image conversion circuit 130 outputs reference coordinates RCRD indicating pixel positions on the first image data IMA, and outputs second image data IMB based on pixel data of the reference coordinates RCRD read from the memory circuit 120 based on the output reference coordinates RCRD. The third error detection circuit 150 performs third error detection on the reference coordinates RCRD output by the image conversion circuit 130. When an error is detected in at least one of the first error detection, second error detection, or third error detection, the control circuit 310 outputs a control signal CNT that turns off the projection of light onto the projection surface.

[0087] If an error occurs in the coordinate conversion during the mapping process, and an image is displayed on the head-up display using the second image data IMB after the mapping process, the visibility of the background may be reduced. According to this embodiment, error detection is performed on the reference coordinates RCRD output by the image conversion circuit 130, thereby determining whether the coordinate conversion during the mapping process is normal. As a result, if no error is detected in the second error detection and the third error detection, it is guaranteed that there is no coordinate conversion error in the second image data IMB received by the receiving interface circuit 210. Furthermore, if an error is detected in at least one of the second error detection and the third error detection, the projection of light onto the projection surface is turned off, and therefore the second image data IMB, which is not guaranteed to be free of coordinate conversion errors, is not displayed on the head-up display 500.

[0088] The control system of the present embodiment described above controls a head-up display. The control system includes an image processing circuit that maps input first image data to second image data to be projected onto the projection surface of the head-up display, a first error detection circuit that performs first error detection on the second image data, a first error code value generation circuit that generates a first error code value from the second image data, and a transmission interface circuit that transmits the second image data. The control system also includes a reception interface circuit that receives the second image data transmitted by the transmission interface circuit, and a second error code value generation circuit that generates a second error code value from the second image data received by the reception interface circuit. The control system also includes a second error detection circuit that performs second error detection on the second image data received by the reception interface circuit based on the first error code value and the second error code value, and a control circuit that outputs a control signal to turn off the projection of light onto the projection surface when an error is detected in at least one of the first error detection or the second error detection.

[0089] According to this embodiment, the first error detection circuit performs first error detection on the second image data, and then the transmission interface circuit and the reception interface circuit transmit and receive the second image data. At this time, the second error detection circuit performs second error detection based on a first error code value generated from the second image data before transmission and a second error code value generated from the second image data after reception. This ensures that the received second image data is the same as the second image data after the first error detection. That is, the result of the first error detection is also guaranteed for the received second image data. Furthermore, when an error is detected in at least one of the first error detection and the second error detection, light projection onto the projection surface is turned off, preventing the image display based on the second image data containing the error and resulting in no light hitting the projection surface. This allows the user to view the background through the screen of the head-up display.

[0090] In addition, in this embodiment, the first error detection circuit may determine a glare index value that is an index value indicating the glare of the head-up display based on the second image data, and perform first error detection based on the glare index value.

[0091] According to this embodiment, the first error detection circuit performs first error detection based on the glare index value, thereby detecting a state in which background visibility is reduced by an image based on the second image data as a glare error. As a result, when no glare error is detected in the first error detection and the second error detection, it is guaranteed that there is no glare error in the second image data received by the receiving interface circuit. Furthermore, when an error is detected in at least one of the first error detection and the second error detection, the projection of light onto the projection surface is turned off, so that the second image data that is not guaranteed to be free of a glare error is not displayed on the head-up display.

[0092] In addition, in this embodiment, the first error detection circuit may perform first error detection by converting the second image data into third image data by an inverse mapping process of the mapping process and comparing the first image data with the third image data.

[0093] According to this embodiment, the first image data is compared with the third image data obtained by performing an inverse mapping process thereon to determine whether the mapping process from the first image data to the second image data is normal. As a result, when no error is detected in the first error detection and the second error detection, it is guaranteed that there is no mapping process error in the second image data received by the receiving interface circuit. Furthermore, when an error is detected in at least one of the first error detection and the second error detection, the projection of light onto the projection surface is turned off, so that the second image data, for which it is not guaranteed that there is no mapping process error, is not displayed on the head-up display.

[0094] In this embodiment, the control system may include a first image circuit and a second image circuit. The first image circuit may include an image processing circuit, a first error detection circuit, a first error code value generation circuit, and a transmission interface circuit. The second image circuit may include a reception interface circuit and a second circuit device including a second error code value generation circuit.

[0095] According to this embodiment, the second image data received by the second circuit device in the subsequent stage is guaranteed to be the same as the second image data after the first error detection in the first circuit device in the preceding stage. As a result, even if the first circuit device performs the first error detection and a second circuit device is provided in the subsequent stage, the result of the first error detection can be substantially guaranteed in the second circuit device in the subsequent stage. Then, when it becomes impossible to guarantee that the second image data IMB is error-free in either the previous or subsequent stage, the projection of light onto the projection surface is turned off.

[0096] In this embodiment, the control system may also include a third error detection circuit. The image processing circuit may include a memory circuit that stores first image data and an image conversion circuit that maps the first image data stored in the memory circuit to second image data. The image conversion circuit may output reference coordinates that indicate pixel positions on the first image data, and output the second image data based on pixel data at the reference coordinates read from the memory circuit based on the output reference coordinates. The third error detection circuit may perform third error detection on the reference coordinates output by the image conversion circuit. The control circuit may output a control signal when an error is detected in at least one of the first error detection, the second error detection, or the third error detection.

[0097] According to this embodiment, error detection is performed on the reference coordinates output by the image conversion circuit to determine whether the coordinate conversion in the mapping process is normal. As a result, if no error is detected in the second error detection and the third error detection, it is guaranteed that there is no coordinate conversion error in the second image data received by the receiving interface circuit. Furthermore, if an error is detected in at least one of the second error detection and the third error detection, the projection of light onto the projection surface is turned off, so that the second image data that is not guaranteed to be free of coordinate conversion errors is not displayed on the head-up display.

[0098] In this embodiment, the control circuit may also output a control signal to turn off the light source of the head-up display.

[0099] According to this embodiment, when an error is detected in at least one of the first error detection or the second error detection, the light source of the head-up display is turned off, and therefore an image is not displayed based on the second image data in which the error occurred.

[0100] In this embodiment, the control system may also include a mask circuit that masks the second image data before it is transmitted by the transmission interface circuit based on the control signal.

[0101] According to this embodiment, when an error is detected in at least one of the first error detection or the second error detection, the second image data is masked before being transmitted by the transmission interface circuit, so that an image is not displayed using the second image data in which the error occurred.

[0102] In this embodiment, the control system may also include a mask circuit that masks the second image data received by the receiving interface circuit based on the control signal.

[0103] According to this embodiment, when an error is detected in at least one of the first error detection or the second error detection, the second image data received by the receiving interface circuit is masked, so that an image is not displayed using the second image data in which the error occurred.

[0104] Moreover, the electronic device of this embodiment includes any of the control systems described above and a head-up display.

[0105] Although the present embodiment has been described in detail above, it will be readily apparent to those skilled in the art that many modifications are possible without substantially departing from the novel features and advantages of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure. For example, a term described at least once in the specification or drawings with a different term having a broader or equivalent meaning may be replaced with that different term anywhere in the specification or drawings. Furthermore, all combinations of the present embodiment and modifications are also included within the scope of the present disclosure. Furthermore, the configurations and operations of the image processing device, display controller, processing device, display driver, head-up display, control system, electronic device, etc. are not limited to those described in the present embodiment, and various modifications are possible. [Explanation of symbols]

[0106] 10...screen, 20, 30...AR display, 50...front vehicle, 100...image processing device, 110...receiving interface circuit, 115...image processing circuit, 120...memory circuit, 130...image conversion circuit, 140...transmitting interface circuit, 150...third error detection circuit, 151...arithmetic circuit, 152...comparison circuit, 160...coordinate address conversion circuit, 170...first error detection circuit, 171...inverse conversion circuit, 172...comparison circuit, 180...first error code value generation circuit, 190...mask circuit, 200...display controller, 210...receiving interface circuit, 220...timing generation circuit, 240...transmitting interface circuit, 27 0...second error detection circuit, 280...second error code value generation circuit, 290...mask circuit, 300...processing device, 310...control circuit, 370...second error detection circuit, 400...control system, 500...head-up display, 510...display driver, 520...backlight controller, 530...light source, 540...display panel, 550...optical system, 600...electronic device, CD1...first error code value, CD2...second error code value, CNT...control signal, ER1...first error detection signal, ER2...second error detection signal, IMA...first image data, IMB...second image data, IMC...third image data, RCRD...reference coordinate

Claims

1. A control system for controlling a head-up display, an image processing circuit that performs mapping processing on the input first image data to second image data to be projected on a projection surface of the head-up display; a first error detection circuit that calculates a glare index value that is an index value indicating the glare of the head-up display based on the second image data, and performs first error detection based on the glare index value; a first error code value generating circuit that generates a first error code value from the second image data; a transmission interface circuit for transmitting the second image data; a receiving interface circuit for receiving the second image data transmitted by the transmitting interface circuit; a second error code value generating circuit that generates a second error code value from the second image data received by the receiving interface circuit; a second error detection circuit that performs second error detection on the second image data received by the receiving interface circuit based on the first error code value and the second error code value; a control circuit that outputs a control signal to turn off projection of light onto the projection surface when an error is detected in at least one of the first error detection and the second error detection; a third error detection circuit; Including, The image processing circuit a storage circuit that stores the first image data; an image conversion circuit that performs the mapping process on the first image data stored in the storage circuit to the second image data; Including, The image conversion circuit outputting reference coordinates indicating pixel positions on the first image data, and outputting the second image data based on pixel data of the reference coordinates read from the storage circuit based on the output reference coordinates; The third error detection circuit performing a third error detection on the reference coordinates output by the image conversion circuit; The control circuit a control system that outputs the control signal when an error is detected in at least one of the first error detection, the second error detection, and the third error detection.

2. A control system for controlling a head-up display, an image processing circuit that performs mapping processing on the input first image data to second image data to be projected on a projection surface of the head-up display; a first error detection circuit that converts the second image data into third image data by an inverse mapping process of the mapping process, and performs first error detection based on a comparison between the first image data and the third image data; a first error code value generating circuit that generates a first error code value from the second image data; a transmission interface circuit for transmitting the second image data; a receiving interface circuit for receiving the second image data transmitted by the transmitting interface circuit; a second error code value generating circuit that generates a second error code value from the second image data received by the receiving interface circuit; a second error detection circuit that performs second error detection on the second image data received by the receiving interface circuit based on the first error code value and the second error code value; a control circuit that outputs a control signal to turn off projection of light onto the projection surface when an error is detected in at least one of the first error detection and the second error detection; a third error detection circuit; Including, The image processing circuit a storage circuit that stores the first image data; an image conversion circuit that performs the mapping process on the first image data stored in the storage circuit to the second image data; Including, The image conversion circuit outputting reference coordinates indicating pixel positions on the first image data, and outputting the second image data based on pixel data of the reference coordinates read from the storage circuit based on the output reference coordinates; The third error detection circuit performing a third error detection on the reference coordinates output by the image conversion circuit; The control circuit a control system that outputs the control signal when an error is detected in at least one of the first error detection, the second error detection, and the third error detection.

3. 3. The control system according to claim 1 or 2, a first circuit device including the image processing circuit, the first error detection circuit, the first error code value generation circuit, and the transmission interface circuit; a second circuit device including the receiving interface circuit and the second error code value generating circuit; A control system comprising:

4. 4. A control system according to claim 1, wherein: The control circuit a control system that outputs the control signal to turn off a light source of the head-up display.

5. 5. A control system according to any one of claims 1 to 4, a mask circuit for masking the second image data before it is transmitted by the transmission interface circuit based on the control signal;

6. 5. A control system according to any one of claims 1 to 4, a mask circuit that masks the second image data received by the receiving interface circuit based on the control signal;

7. A control system according to any one of claims 1 to 6; the head-up display; 1. An electronic device comprising:

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