In-vehicle video processing device, in-vehicle video processing method, and in-vehicle video processing system

Abstract

Provided are an in-vehicle video processing device and in-vehicle video processing system capable of more appropriately switching a video to be output to a display between a camera video and a composite video. The in-vehicle video processing device is provided with: a main microcomputer that generates a second video signal in which an image for assisting in driving a vehicle is superimposed on a first video signal that is input from a camera mounted in the vehicle and is obtained by imaging the surroundings of the vehicle; and a sub-microcomputer that when receiving a first instruction signal for outputting a video signal to the display, outputs the second video signal to the display when the main microcomputer is in a state in which the second video signal can be generated, and outputs the first video signal to the display when the main microcomputer is in a state in which the second video signal cannot be generated.

Description

In-vehicle image processing device, in-vehicle image processing method, and in-vehicle image processing system

[0001] The present invention relates to an in-vehicle image processing device, an in-vehicle image processing method, and an in-vehicle image processing system.

[0002] A system has been proposed that assists vehicle driving by using a microcomputer to generate a composite image in which guide lines or the like are superimposed on a camera image of the surroundings of the vehicle. Patent Document 1 proposes a technology for resetting the microcomputer when an abnormality in the composite image generated by the microcomputer is detected.

[0003] JP 2017-081445 A

[0004] Incidentally, if a composite image generated by a processing circuit such as a microcomputer is input to a control unit, the control unit can detect an abnormality in the processing circuit by monitoring whether the composite image is normal. Therefore, the control unit can prevent the generation of an abnormal composite image due to an abnormality in the processing circuit by resetting the processing circuit when the composite image is abnormal. However, if the composite image is not input to the control unit, it is unclear whether the composite image is not input to the control unit due to an abnormality in the processing circuit or whether the composite image is not input to the control unit because it is not the right time to input the composite image. Therefore, if the composite image is not input to the control unit, an abnormality in the processing circuit cannot be detected.

[0005] One aspect of the disclosed technology aims to provide an in-vehicle image processing device, an in-vehicle image processing method, and an in-vehicle image processing system that can more appropriately switch the image to be output to the display between camera image and synthetic image.

[0006] One aspect of the disclosed technology is exemplified by the following in-vehicle image processing device: The in-vehicle image processing device includes a main microcomputer that generates a second video signal by superimposing an image that assists driving of the vehicle on a first video signal that is input from a camera mounted on the vehicle and captures an image of the surroundings of the vehicle, and a sub-microcomputer that, upon receiving a first instruction signal to output a video signal to a display, causes the main microcomputer to output the second video signal to the display if the main microcomputer is in a state where it can generate the second video signal, or causes the main microcomputer to output the first video signal to the display if it is not in a state where it can generate the second video signal.

[0007] According to the disclosed technology, it is possible to more appropriately switch the image to be output on the display between the camera image and the composite image.

[0008] Fig. 1 is a diagram illustrating an example of a vehicle according to an embodiment. Fig. 2 is a diagram illustrating an example of the hardware configuration of an in-vehicle image processing system according to an embodiment. Fig. 3 is a diagram illustrating an example of a camera image captured by a camera according to an embodiment. Fig. 4 is a diagram illustrating an example of a guide image generated by an SoC according to an embodiment. Fig. 5 is an example of a processing flow of a sub-microcomputer according to an embodiment.

[0009] <Embodiments> Hereinafter, embodiments will be described with reference to the drawings. Fig. 1 is a diagram illustrating an example of a vehicle 100 according to an embodiment. Fig. 1 is a diagram of the vehicle 100 as viewed from above. In Fig. 1, the ceiling is omitted in order to illustrate the interior of the vehicle 100. The vehicle 100 is, for example, a passenger car.

[0010] The vehicle 100 includes passenger seats, which include a driver's seat 1, a passenger seat 2, a right rear seat 3, a center rear seat 4, and a left rear seat 5. The driver's seat 1 and the passenger seat 2 are arranged in a line along the width direction of the vehicle 100. The right rear seat 3, the center rear seat 4, and the left rear seat 5 are arranged in a line along the width direction of the vehicle 100 behind the driver's seat 1 and the passenger seat 2. A dashboard 10 is arranged in front of the driver's seat 1 and the passenger seat 2. A steering wheel 20 is arranged in front of the driver's seat 1. A display 30 is arranged on the dashboard 10. A shift lever 40 is arranged between the driver's seat 1 and the passenger seat 2. For example, when the vehicle 100 is to be driven in reverse (backed up), the shift lever 40 is switched to the reverse range. A camera C1 that captures images of the rear of the vehicle 100 is provided at the rear of the vehicle 100 and in the center of the width direction of the vehicle 100. The location where the camera C1 is installed is not limited to the rear and center of the vehicle 100 in the width direction, but may be any location that allows the rear of the vehicle 100 to be suitably photographed.

[0011] The vehicle 100 is equipped with a front right tire 61, a front left tire 62, a rear right tire 64, and a rear left tire 65. When the front right tire 61 and the front left tire 62 are not distinguished from each other, they are also referred to as front wheels 63. When the rear right tire 64 and the rear left tire 65 are not distinguished from each other, they are also referred to as rear wheels 66.

[0012] 2 is a diagram showing an example of the hardware configuration of an in-vehicle image processing system 300 according to an embodiment. The in-vehicle image processing system 300 includes a camera electronic control unit (ECU) 301 and an in-vehicle image processing device 200. The in-vehicle image processing device 200 includes a video integrated circuit (IC) 201, a system-on-a-chip (SoC) 202, a sub-microcomputer 203, and connection buses B1, B2, B3, B4, B5, B6, B7, B8, and B9.

[0013] The in-vehicle image processing system 300 is a system that assists in reversing the vehicle 100 when parking in a parking lot, etc., by outputting to the display 30 a guide image in which a code related to reversing the vehicle 100 is superimposed on the camera image captured by the camera C1.

[0014] The camera C1 and the camera ECU 301 are connected by connection buses B1 and B2. The camera ECU 301 and the video IC 201 are connected by connection bus B3. The video IC 201 and the SoC 202 are connected by connection buses B4 and B5. The SoC 202 and the sub-microcomputer 203 are connected by connection buses B6 and B7. The sub-microcomputer 203 and the video IC 201 are connected by connection bus B8. The video IC 201 and the display 30 are connected by connection bus B9.

[0015] The camera ECU 301 is a device that controls the camera C1. For example, when the camera ECU 301 detects that the shift lever 40 of the vehicle 100 has been shifted to the reverse range, the camera ECU 301 sends a start image capture command via the connection bus B1, causing the camera C1 to start image capture. Furthermore, when the camera ECU 301 detects that the shift lever 40 has been shifted to the reverse range, the camera ECU 301 sends a camera display request to the sub-microcomputer 203 via the connection bus B2. Furthermore, when the camera ECU 301 detects that the shift lever 40 has been shifted to a range other than the reverse range, the camera ECU 301 sends a stop image capture command via the connection bus B1, causing the camera C1 to stop image capture. Furthermore, the camera ECU 301 sends a camera display stop request to the sub-microcomputer 203 via the connection bus B2. Furthermore, the camera ECU 301 receives camera images captured by the camera C1 via the connection bus B2 and outputs the received camera images to the video IC 201 of the in-vehicle image processing device 200 via the connection bus B3. The camera ECU 301 is an example of a "camera control unit."

[0016] 3 is a diagram showing an example of a camera image 3011 captured by the camera C1 in the embodiment. As described above, the camera image 3011 is captured by the camera C1 and input to the video IC 201. FIG. 3 illustrates the camera image 3011 input to the video IC 201 when the vehicle 100 is reversed and parked in a parking lot 810. The camera image 3011 includes the rear line 801 and side lines 802 and 803 of the parking lot 810 captured by the camera C1. The camera image 3011 is an example of a "first video signal."

[0017] 2 , video IC 201 is an integrated circuit that receives camera video 3011 input from camera ECU 301 via connection bus B3. Video IC 201 has switch SW1, which includes contacts P1 and P2. When switch SW1 is switched to contact P1, a path is formed from camera ECU 301 to display 30 via connection buses B3, B4, B5, and B9. When switch SW1 is switched to contact P2, a path is formed from camera ECU 301 to display 30 via SoC 202 via connection buses B3 and B9.

[0018] The video IC 201 switches the contact of the switch SW1 in response to a path control signal from the sub-microcomputer 203. When the video IC 201 receives a first path control signal from the sub-microcomputer 203, it switches the switch SW1 to the contact P1 side. By switching the switch SW1 to the contact P1 side, a guide video generated by the SoC 202 is output to the display 30. Details of the guide video will be described later.

[0019] Furthermore, when the video IC 201 receives a second path control signal from the sub-microcomputer 203, it switches the switch SW1 to the contact P2 side. Switching the switch SW1 to the contact P2 side causes the camera video 3011 output to the contact P2 to be output to the display 30. That is, when the video IC 201 receives the second path control signal, the camera video 3011, not the guide video, is output to the display 30. Hereinafter, in this specification, the path through which the camera video is input from the video IC 201 to the SoC 202 and the guide video is output from the SoC 202 to the display 30 via the contact P1 is also referred to as the first path. Furthermore, the path through which the camera video 3011 is output to the display 30 via the contact P2 of the video IC 201 (i.e., without passing through the SoC 202) is also referred to as the second path. The video IC 201 is an example of a "video controller."

[0020] The SoC 202 generates a guide video by superimposing a code related to reversing the vehicle 100 on the camera video 3011 input from the video IC 201 via the connection bus B4. The SoC 202 then outputs the generated guide video to the video IC 201 via the connection bus B5. Furthermore, upon receiving an ON notification from the sub-microcomputer 203 via the connection bus B6 indicating that image capture by the camera C1 has begun, the SoC 202 returns a detection response indicating receipt of the ON notification to the sub-microcomputer 203 via the connection bus B7. Upon receiving the ON notification, the SoC 202 then accepts the input of the camera video 3011 from the video IC 201 via the connection bus B4. The SoC 202 is, for example, a circuit in which circuits related to image processing are integrated into one chip. The detection response is an example of a "response signal."

[0021] FIG. 4 is a diagram showing an example of a guide video 2021 generated by the SoC 202 in an embodiment. The guide video 2021 is an image in which a symbol 2022 relating to reversing the vehicle 100 is superimposed on the camera video 3011. The symbol 2022 relating to reversing includes, for example, a vehicle width line 2023 and an approach line 2024. The vehicle width line 2023 is a symbol indicating the width of the vehicle 100 in the guide video 2021. The approach line 2024 is a symbol indicating a position a predetermined distance (e.g., 50 cm) from the rear end of the vehicle 100. The in-vehicle video processing device 200 supports the reversing of the vehicle 100 by outputting the guide video 2021 to the display 30. The SoC 202 is an example of a "main microcomputer." The guide video 2021 is an example of a "second video signal." The symbol 2022 relating to reversing is an example of an "image for assisting vehicle driving."

[0022] Returning to FIG. 2 , the sub-microcomputer 203 is a microcomputer that controls the video IC 201 and the SoC 202. The sub-microcomputer 203 includes, for example, a processor and a memory. When the sub-microcomputer 203 receives a camera display request from the camera ECU 301 via the connection bus B2, it sends an ON notification to the SoC 202 via the connection bus B6. When the sub-microcomputer 203 receives a camera display end request from the camera ECU 301 via the connection bus B2, it sends a camera OFF notification to the SoC 202 via the connection bus B6. The camera display request is an example of a "first instruction signal." The ON notification is an example of a "second instruction signal."

[0023] If the sub-microcomputer 203 receives a detection response from the SoC 202 via the connection bus B7 within a predetermined time after sending the ON notification, it selects the first path. The sub-microcomputer 203 sends a first path control signal to the video IC 201 via the connection bus B8, which causes the path of the camera image captured by the camera C1 to be the first path. The first path control signal switches the switch SW1 to contact P1, thereby establishing the first path. As a result of the first path being established, the guide image 2021 is output on the display 30. Furthermore, if the sub-microcomputer 203 does not receive a detection response from the SoC 202 via the connection bus B7 within a predetermined time after sending the ON notification, it selects the second path. The sub-microcomputer 203 sends a second path control signal to the video IC 201 via the connection bus B8, which causes the path of the camera image captured by the camera C1 to be the second path. The second path control signal switches the switch SW1 to contact P2, thereby establishing the second path. As a result of selecting the second path, a camera image 3011 is output to the display 30. Note that if the selected path is already formed by the switch SW1 (for example, if the switch SW1 is already set to the contact P1 side when the first path is selected), the sub-microcomputer 203 does not need to send the first path control signal or the second path control signal. The sub-microcomputer 203 is an example of a "sub-microcomputer." The first path control signal is an example of a "third instruction signal." The second path control signal is an example of a "fourth instruction signal." Receiving a detection response from the SoC 202 via the connection bus B7 within a predetermined time after issuing an ON notification is an example of a "state in which the main microcomputer can generate the second video signal." Not receiving a detection response from the SoC 202 via the connection bus B7 within a predetermined time after issuing an ON notification is an example of a "state in which the main microcomputer cannot generate the second video signal."

[0024] Note that sub-microcomputer 203 may detect whether SoC 202 is in a state where it can generate the second video signal (guide video 2021) by a method other than that described above. For example, sub-microcomputer 203 may directly monitor guide video 2021 output from SoC 202, and if guide video 2021 is output within a predetermined time after the ON notification is sent, detect that SoC 202 is in a state where it can generate guide video 2021, and if the second video signal is not output within the predetermined time, detect that SoC 202 is in a state where it cannot generate guide video 2021.

[0025] The sub-microcomputer 203 may also monitor the processing load of the SoC 202 to detect whether the SoC 202 is in a state where it can generate the guide video 2021. For example, the sub-microcomputer 203 may monitor the processing load of the SoC 202 based on the count value of a watchdog timer of the SoC 202, and if the processing load does not exceed a predetermined value (e.g., 80%), detect that the SoC 202 is in a state where it can generate the guide video 2021, and if the processing load exceeds a predetermined value, detect that the SoC 202 is in a state where it cannot generate the guide video 2021.

[0026] For example, the sub-microcomputer 203 may monitor the number of functions being executed simultaneously on the SoC 202, and if the number of functions being executed on the SoC 202 does not exceed a predetermined value (e.g., three), detect a state in which the SoC 202 can generate the guide video 2021, and if the number exceeds a predetermined value, detect a state in which the SoC 202 cannot generate the guide video 2021. Specifically, the sub-microcomputer 203 may detect a state in which the SoC 202 can generate the guide video 2021 when one or two of three functions, for example, "music playback," "navigation route guidance," and "hands-free calling," are being executed simultaneously on the SoC 202, and may detect a state in which the SoC 202 cannot generate the guide video 2021 when three functions are being executed simultaneously.

[0027] For example, the sub-microcontroller 203 may monitor the types of functions being executed simultaneously on the SoC 202, and if the function being executed on the SoC 202 is a function with a low processing load such as "radio reception" or "music playback," it may detect a state in which the SoC 202 is able to generate the guide video 2021, and if the function being executed on the SoC 202 is a function with a high processing load such as "navigation route search" or "voice recognition," it may detect a state in which the SoC 202 is unable to generate the guide video 2021.

[0028] 5 shows an example of a processing flow of the sub-microcomputer 203 according to the embodiment. It is assumed that the first path is set at the start of the processing flow shown in FIG. 5. Hereinafter, an example of the processing flow of the sub-microcomputer 203 will be described with reference to FIG. 5.

[0029] In step S1, the sub-microcomputer 203 determines whether or not a camera display request has been received from the camera ECU 301. The camera display request is output to the sub-microcomputer 203 by the camera ECU 301, which detects that the shift lever 40 has been switched to the reverse range. If a camera display request has been received (YES in step S1), the process proceeds to step S2. If a camera display request has not been received (NO in step S1), the process of step S1 is repeated.

[0030] In step S2, the sub-microcomputer 203 sends an ON notification to the SoC 202. In step S3, the sub-microcomputer 203 waits for a predetermined time after sending the ON notification in step S2. The predetermined time is determined appropriately based on the time from when the sub-microcomputer 203 sends the ON notification until when the sub-microcomputer 203 receives a detection response from a sub-microcomputer 203 that is operating normally.

[0031] In step S4, the sub-microcomputer 203 determines whether or not a detection response has been received from the SoC 202 within the predetermined time period in step S3. If a detection response has been received (YES in step S4), the process proceeds to step S5. If a detection response has not been received (NO in step S5), the process proceeds to step S6.

[0032] In step S5, the sub-microcomputer 203 selects the first path as the path for processing the camera image, that is, the sub-microcomputer 203 sets the switch SW1 of the video IC 201 to the contact P1 side.

[0033] In step S6, the sub-microcomputer 203 selects the second path as the path for processing the camera image. That is, the sub-microcomputer 203 sets the switch SW1 of the video IC 201 to the contact P2 side.

[0034] <Effects of the Present Embodiment> In the present embodiment, if the sub-microcomputer 203 does not receive a detection response from the SoC 202 within a predetermined time after sending the ON notification, it can determine that an abnormality, such as a failure or overload, has occurred in the SoC 202. When the sub-microcomputer 203 determines that an abnormality has occurred in the SoC 202, it selects a first path to output the camera image 3011 to the display 30 instead of the guide image 2021. In the first path, the camera image 3011 is output to the display 30 without passing through the SoC 202. Therefore, even if the SoC 202 is at least temporarily unable to generate the guide image 2021 due to a failure, overload, or the like, the guide image 2021 can be output to the display 30. Therefore, according to the present embodiment, even if an abnormality, such as a failure, occurs in the SoC 202, the camera image 3011 captured by the camera C1 can be output to the display 30. Consequently, according to the present embodiment, outputting the camera image 3011 can assist in reverse driving of the vehicle 100.

[0035] In this embodiment, the SoC 202 has a switch SW1 including a contact P1 connected to the display 30 via the SoC 202 and a contact P2 connected to the display 30 without via the SoC 202. By switching between the contact P1 and the contact P2 in response to an instruction from the sub-microcomputer 203, the image to be output to the display 30 can be switched between the camera image 3011 and the guide image 2021. Therefore, according to this embodiment, the image to be output to the display 30 can be switched between the guide image 2021 and the camera image 3011 by a simple operation of switching the contact of the switch SW1.

[0036] Furthermore, in this embodiment, when the shift lever 40 is switched to the reverse range, the camera ECU 301 sends a camera display request to the sub-microcomputer 203, and upon receiving the camera display request, the sub-microcomputer 203 sends an ON notification to the SoC 202. In other words, the ON notification can be considered an instruction indicating that the shift lever 40 has been switched to the reverse range. In this embodiment, if an abnormality is detected in the SoC 202 when the shift lever 40 is switched to the reverse range, the camera image 3011 is output to the display 30. Therefore, according to this embodiment, even when the guide image 2021 cannot be output, the camera image 3011 can be used to assist in reversing the vehicle 100.

[0037] In this embodiment, there are provided a connection bus B6 through which the sub-microcomputer 203 sends an ON notification and a connection bus B7 through which the sub-microcomputer 203 receives a detection response from the SoC 202. However, the connection bus B6 and the connection bus B7 may be a single bus. In this case, the sub-microcomputer 203 simply sends an ON notification to the SoC 202 via the single bus, and the SoC 202 simply returns a detection response to the sub-microcomputer 203 via the single bus.

[0038] In this embodiment, the camera C1 captures an image of the rear of the vehicle 100, but the capture range of the camera C1 is not limited to the rear of the vehicle 100. The camera C1 may capture an image of the front of the vehicle 100 or may capture an image of the 360-degree surroundings of the vehicle 100. The SoC 202 may generate a guide image by superimposing a code that assists the driver of the vehicle 100 on the image captured by the camera C1. Examples of the code that assists the driver of the vehicle 100 include a code indicating an obstacle around the vehicle 100, a code indicating a person around the vehicle 100, and a code indicating a vehicle around the vehicle 100. By displaying such a guide image on the display 30, the vehicle 100 is supported in traveling in various directions other than reverse.

[0039] Incidentally, it is conceivable that a failure or overload may occur in the SoC 202 after returning the detection response to the sub-microcomputer 203. In such a case, the guide image 2021 input from the SoC 202 to the video IC 201 may become a fixed image, i.e., an image that does not change over time. If the guide image 2021 input from the SoC 202 becomes a fixed image after receiving the first path control signal, the video IC 201 may output the camera image 3011 to the display 30 by switching the switch SW1 to the contact P2 side. For example, if the pixel values ​​of a frame of the guide image 2021 input from the SoC 202 do not change for a predetermined period of time, the video IC 201 may determine that the guide image 2021 is a fixed image. By switching the image output to the display 30 from the fixed image to the camera image 3011, reverse assistance for the vehicle 100 continues even if a failure or overload occurs in the SoC 202 while the guide image 2021 is being output. A stuck image is an example of a "stuck image signal."

[0040] In this embodiment, the video IC 201, the SoC 202, and the sub-microcomputer 203 are illustrated in FIG. 2 as independent integrated circuits, but the video IC 201, the SoC 202, and the sub-microcomputer 203 do not have to be independent integrated circuits. The video IC 201, the SoC 202, and the sub-microcomputer 203 may be implemented as multiple microcomputer cores on a single silicon chip, for example. Furthermore, the sub-microcomputer 203 may be implemented as hardware that includes the functions of the video IC 201.

[0041] The embodiments and modifications disclosed above can be combined with each other.

[0042] 1. Driver's seat 2. Passenger seat 3. Right rear seat 4. Center rear seat 5. Left rear seat 10. Dashboard 20. Steering wheel 30. Display 40. Shift lever 61. Front right tire 62. Front left tire 63. Front wheel 64. Rear right tire 65. Rear left tire 66. Rear wheel 100. Vehicle 200. In-vehicle image processing device 201. Video IC 202. SoC 203. Sub-microcomputer 300. In-vehicle image processing system 301. Camera ECU 800. Parking lot 801. Rear line 802. Side line 803. Side line 810. Parking lot 2021. Guide image 2022. Code related to reversing 2023. Vehicle width line 2024: Line of approach 3011: Camera image B1: Connection bus B2: Connection bus B3: Connection bus B4: Connection bus B5: Connection bus B6: Connection bus B7: Connection bus B8: Connection bus B9: Connection bus C1: Camera P1: Contact point P2: Contact point SW1: Switch

Claims

1. An in-vehicle image processing device comprising: a main microcomputer that generates a second video signal by superimposing an image that assists in driving the vehicle on a first video signal that is input from a camera mounted on the vehicle and captures an image of the surroundings of the vehicle; and a sub-microcomputer that, upon receiving a first instruction signal to output a video signal to a display, outputs the second video signal to the display if the main microcomputer is in a state where it can generate the second video signal, or outputs the first video signal to the display if the main microcomputer is not in a state where it can generate the second video signal.

2. The in-vehicle image processing device of claim 1, wherein, when the sub-microcomputer receives the first instruction signal, it sends a second instruction signal to the main microcomputer to cause it to generate the second video signal, and then, if a response signal to the second instruction signal is received from the main microcomputer, it outputs the second video signal to the display, and if the response signal is not received, it outputs the first video signal to the display.

3. An in-vehicle image processing device as described in claim 1, further comprising a video controller that receives the first video signal and the second video signal and outputs either one of them to the display, wherein when the sub-microcomputer receives the first instruction signal, if the main microcomputer is in a state where it can generate the second video signal, it sends a third instruction signal to the video controller to cause the video controller to output the second video signal to the display, and if the main microcomputer is in a state where it cannot generate the second video signal, it sends a fourth instruction signal to the video controller to cause the video controller to output the first video signal to the display.

4. The in-vehicle image processing device described in claim 3, wherein when the image controller receives the third instruction signal from the sub-microcomputer, if the second image signal input from the main microcomputer is a fixed image signal in which the pixel values ​​of the frame do not change over time, the image controller outputs the first image signal to the display instead of the second image signal.

5. The in-vehicle image processing device according to any one of claims 1 to 4, wherein the first instruction signal is a signal indicating that a shift lever of the vehicle has been switched to a reverse range.

6. An in-vehicle image processing method comprising: a generation step of generating a second video signal by superimposing an image that assists driving of the vehicle on a first video signal that captures the surroundings of the vehicle and is input from a camera mounted on the vehicle; and a control step of, upon receiving a first instruction signal to output a video signal to a display, outputting the second video signal to the display if the second video signal was generated in the generation step, or outputting the first video signal to the display if the second video signal was not generated in the generation step.

7. An in-vehicle image processing system comprising: a camera mounted on a vehicle; a camera control unit that causes the camera to start capturing images and outputs the camera image captured by the camera; a main microcomputer that generates a second video signal by superimposing an image that assists in driving the vehicle on a first video signal that captures the surroundings of the vehicle and is input from the camera via the camera control unit; and a sub-microcomputer that, when receiving a first instruction signal from the camera control unit to output a video signal to a display, causes the main microcomputer to output the second video signal to the display if the main microcomputer is in a state where it can generate the second video signal, and causes the main microcomputer to output the first video signal to the display if it is not in a state where it can generate the second video signal.

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