KR102466417B1 - System of video output for transmitting image signals to image display device and method for changing displayed video using the same - Google Patents

Abstract

A method of changing a display image output from an image output system operated by at least one processor to an image display device, wherein a first image signal and a second image signal are received, and a first image selection signal pre-selected at a first time point. Based on the first video sync signal and the received first video vertical synchronization signal, the first video selection state is maintained and the received first video signal is delivered to the video display device. If the second video selection signal is received while the first video signal is being transmitted, the state is switched from the first video selection state to the standby state. After switching to the second image selection state, the received second image is transmitted to the image display device.

Description

System of video output for transmitting image signals to image display device and method for changing displayed video using the same}

The present invention relates to a video output system for transmitting a video signal to a video display device and a display video changing method using the same.

Various driver driving assistance devices such as a navigation device, an advanced driver assistance system (ADAS), and an on board diagnostics (OBD) are installed in a recently developed vehicle. In addition, a Head Up Display (HUD) is also used for the driver's safe driving.

A driving assistance device or HUD applied to a vehicle as described above is composed of an image display device such as an LCD panel that displays an image and an image output system that transmits an image signal to the image display device. And, the video output system is composed of a transmission device for transmitting the video signal to the video display device and a video signal generating device for generating the video signal.

A plurality of video signal generating devices may exist, and may additionally include a video signal multiplexer when video content to be output to the video display device is changed. The video signal multiplexer selects one of a plurality of video signals and transmits it to the video display device through a transmission device.

At this time, since all of the plurality of video signal generators operate independently, video signals input to the video signal multiplexer are not synchronized with each other. Therefore, when trying to change an image being displayed through an image display device, there are problems in that various types of errors occur due to a time difference between an existing image signal and an image signal to be changed, and timing of the change.

Accordingly, the present invention provides a video output for transmitting a video signal to a video display device capable of changing a video signal capable of changing the video content displayed without errors while satisfying the number of pixels per frame and the minimum vertical signal waiting time defined by the video display device. A system and a method for changing an expression image using the same are provided.

As a method of changing a display image output to an image display device by an image output system operated by at least one processor, which is one feature of the present invention for achieving the technical problem of the present invention,

Receiving a first video signal and a second video signal while maintaining a standby state, based on a first video selection signal previously selected at a first time point and a first video vertical sync signal received, transitioning from the standby state Maintaining a 1 image selection state and transferring the received first image signal to the image display device, if a second image selection signal is received while the first image signal is being transmitted, the first image selection state Switching to a standby state, and if a second video vertical synchronizing signal is received at a second time point while maintaining the standby state, switching from the standby state to the second image selection state, and displaying the received second image as the image and forwarding to the presentation device.

In the step of switching to the standby state, if a first video vertical synchronizing signal for the first video signal is received between the first time point and the second time point, the received first image is not transmitted to the image display device. steps may be included.

The step of transferring the received second image to the image display device may include: switching from the standby state to the second image selection state when a rising edge of the second image vertical sync signal is input; It may include transmitting a second image to the image display device.

In the step of switching to the standby state, the video display device may output the first video transmitted at the first time point.

As a video output system for outputting a video signal to a video display device, which is another feature of the present invention for achieving the technical problem of the present invention,

According to a control signal from the outside, one of the first and second video selection signals is generated so that one of the first and second video signals is output to the video display device. When the processor is initially driven, it maintains a standby state, and switches from the standby state to an image selection state according to the image selection signal generated by the processor and the video vertical synchronization signal for each video signal, and the first image signal or the second image A video signal multiplexer that selects neither the first video signal nor the second video signal input when either one of the video signals is selected or the video signal is switched from the video selection state to the standby state, and the first video signal or the second video signal is input. and a transmitter for outputting a video signal selected from among the two video signals to the video display device.

The video signal multiplexer receives both the first video signal and the second video signal, the video selection signal is the first video selection signal, and the first video generator generates the first video signal. When a vertical synchronization signal is received, the standby state may be switched to the first image selection state.

When the video signal multiplexer receives the second video selection signal from the processor and the first video vertical synchronizing signal from the first video generator in the first video selection state, the first video selection state can switch to the standby state.

When the video signal multiplexer receives a second video vertical sync signal from a second video generator that generates the second video while maintaining the standby state, the video signal multiplexer switches from the standby state to the second image selection state, and receives A second image may be selected.

The first video signal generating unit for generating a first video signal composed of a plurality of first video frames to be output from the video display device and generating the first video vertical sync signal for each preset first video frame; and the second video signal generator configured to generate a second video signal composed of a plurality of second video frames to be output from the video display device, and to generate the second video vertical synchronizing signal for each preset second video frame. can include

According to the present invention, it is possible to change the displayed video content without error while satisfying the number of pixels per frame and the minimum vertical signal waiting time defined by the video display device.

1 is an exemplary view of a general video output system.
2 is an exemplary operation diagram of a general video output system.
3 is an exemplary view of a screen abnormality that occurs when video content is changed in a general video output system.
4 is a structural diagram of an image output system according to an embodiment of the present invention.
5 is an exemplary state diagram of an image output system according to an embodiment of the present invention.
6 is an exemplary diagram illustrating operation timing of an image output system according to an embodiment of the present invention.
7 is a flowchart of a method of changing displayed video content according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

Hereinafter, a video output system for transmitting a video signal to a video display device according to an embodiment of the present invention and a display video change method using the same will be described with reference to the drawings. Prior to describing an embodiment of the present invention, a general video output system will be first described with reference to FIGS. 1 to 3 .

1 is an exemplary view of a general video output system.

As shown in FIG. 1, an image output system 20 for transmitting an image signal to an image display device such as an LCD 10 includes at least one image signal generator 21 that generates an image signal, and an image signal generator. A Low Voltage Differential Signal (LVDS) transmission unit 23 for transmitting the image signal generated by the unit 21 to the LCD 10 is included. Here, the video signal generator 21 may be included inside the video output system 20 or installed outside the video output system 20 to provide a video signal to the video output system 20 .

Also, the video signal generator 21 may be configured with a plurality of pieces such as the first video signal generator 21-1 and the second video signal generator 21-2. In this case, the image to be output through the LCD 10 can be changed, and for this purpose, the image signal multiplexer 22 can be additionally configured.

The video signal multiplexer 22 selects one of a plurality of video signals transmitted from the first video signal generator 21-1 and the second video signal generator 21-2 and transmits it to the LVDS transmission unit 23. is a multiplexer that When the image output to the LCD 10 needs to be changed, the image signal multiplexer 22 changes the selected image through a control signal transmitted from the outside and changes the image signal transmitted to the LVDS transmitter 23. Here, the control signal may be generated by a processor (not shown) in the image output system 20 or may be input from the outside.

At this time, both the first video signal generator 21-1 and the second video signal generator 21-2 operate independently. Accordingly, the video signals transmitted to the video signal multiplexer 22 are not synchronized with each other.

Therefore, when changing the image displayed on the LCD 10 using the general image output system 20, various errors may occur. This will be described with reference to FIGS. 2 and 3 .

2 is a diagram illustrating an operation of a general video output system, and FIG. 3 is a diagram illustrating an abnormal screen occurring when video content is changed in a general video output system.

First, as shown in FIG. 2, the first image source ① generated by the first image signal generator 21-1 and the second image source generated by the second image signal generator 21-2 (②) is an input video signal of the video signal multiplexer 22.

The video signal multiplexer 22 selects and outputs the first video source when the multiplexer selection signal is at the first level (low level) (③), and selects and outputs the second video source when it is at the second level (high level). Assume that it is set to

In FIG. 2 , more errors occur than the number of predefined pixels in the number of pixel data in the frame section indicated as the error-occurring frame. Also, in some cases, an error in which pixel data smaller than the number of pixels of a defined frame is transmitted in a corresponding frame section may occur. Also, an error may occur in which a vertical signal waiting (vertical blank) section in which the video vertical synchronization (vsync) is at a high level is shorter than a predetermined minimum length.

That is, the first image source and the second image source are not synchronized, but the number of pixels in one frame is the same. However, in the error occurrence frame section, since the reduced frame of the first image source and the reduced frame of the second image source are combined to form one frame, it is impossible to match the number of pixels in the predefined frame. In the case of FIG. 2, an example of a case where the number of pixels in an error occurrence frame section is greater than the number of pixels in a predefined frame is shown.

Here, the number of pixels in a predefined frame or the defined minimum vertical signal waiting period means a predefined condition for the video display device 10 to operate normally. If this condition is not satisfied, normal operation of the video display device 10 cannot be expected.

Therefore, as shown in FIG. 3 , an instantaneous screen abnormality may occur in a frame in which a problem occurs. In addition, a screen abnormality may occur in all frames after the frame in which the problem occurs.

That is, as shown in (a) of FIG. 3, the first image signal generator 21-1 generates the first image, and as shown in (b) of FIG. 3, the second image signal generator 21-1 It is assumed that (21-2) generates the second image. When the display target image is changed from the first image to the second image while the image display device 10 is displaying the first image on the screen, a condition predefined by the image display device 10 may not be satisfied. can

Accordingly, as shown in (c) of FIG. 3 , while switching from the first image to the second image, the two images may be displayed on the screen at the same time or a screen-pull phenomenon may occur. Therefore, in the embodiment of the present invention, while satisfying the number of pixels per frame and the minimum vertical signal waiting time defined by the image display device, even if the image to be displayed is changed, the image display device prevents two images from being displayed at the same time or the screen rolling phenomenon does not occur. We propose a video output system that transmits video signals and a method for changing the displayed video using the same.

4 is a structural diagram of an image output system according to an embodiment of the present invention.

As shown in FIG. 4 , the video output system 100 that transmits video signals to the video display device 30 includes at least one video signal generator 110 that generates video signals, and the video signal generator 110. ) includes a low voltage differential signal (LVDS) transmitter 130 that transmits the video signal generated by the image display device 30.

Here, the video signal generator 110 may be included inside the video output system 100 (110-1, 110-2) or installed outside the video output system 110 (110-3) to the video output system In (100), a video signal may be provided.

As shown in FIG. 4 , a plurality of image signal generators 110 may be formed. In the embodiment of the present invention, only three image signal generators 110-1 to 110-3 are shown for convenience of explanation, and for convenience of explanation, the image signals generated by the two image signal generators are used as an image display device. The case of transmission in (30) will be described. The video signal generators 110-1 to 110-3 may be any device capable of generating a video signal, such as a rear camera of a vehicle, a multimedia playback device, a warning screen playback device, or a cluster screen playback device.

When a plurality of image signal generators 110 are configured as described above, an image signal multiplexer 120 may be additionally configured to change an image to be output through the image display device 30 . The video signal multiplexer 120 selects one of a plurality of video signals transmitted from the plurality of video signal generators 110-1 to 110-3 and transmits it to the LVDS transmission unit 130.

When an image output to the image display device 30 needs to be changed, the image signal multiplexer 120 changes the image signal transmitted to the LVDS transmitter 130 based on the control signal transmitted from the processor 140. Here, the control signal includes image information selected by the driver. In the embodiment of the present invention, the processor 140 is shown as being located inside the video output system 100 for convenience of description, but may be located outside the video output system 100 and transmit control signals.

When the video signal multiplexer 120 is initially driven and receives a control signal from the processor 140, the video signal generator 110 transitions to a state ready to receive the video signals generated respectively.

Further, when the video signal multiplexer 120 receives the selected video control signal including the video signal information selected by the user from the processor 140, the video signal generator 110 receives the selected video signal from the LVDS transmission unit ( 130). Here, the selected image control signal includes a pulse signal corresponding to the selected image (hereinafter referred to as 'selected image control signal' for convenience of explanation).

The video signal multiplexer 120 receives the video signal from the video signal generator 110 that generates a video signal corresponding to the pulse signal based on the selected video control signal. Then, the received video signal is transmitted to the LVDS transmitter 130. At this time, the video signal multiplexer 120 transmits the corresponding video signal to the LVDS transmission unit 130 in frame units. When the video vertical sync signal rises from the rising edge of the video vertical sync signal of the next frame, the rising edge occurs. The video signal is transmitted frame by frame until

At this time, when the video signal multiplexer 120 receives a control signal requesting a change of the video content displayed from the processor 140 (hereinafter referred to as a 'change control signal'), the video signal multiplexer 120 controls the selected video. The state transitions from the video transmission state to the standby state (IDLE state) based on the edge states of the signal and the video vertical synchronization signal.

At this time, the standby state means a state in which the video signal multiplexer 120 does not select any video signal even though the video signal multiplexer 120 receives video signals from the plurality of video signal generators 110 . When the video signal multiplexer 120 maintains the standby state, the video display device 30 recognizes the standby interval as a vertical blank interval.

Here, an example in which the video signal multiplexer 120 transitions the state according to the edge states of the selected video control signal and the video vertical synchronization signal will be described with reference to FIG. 5 . In the embodiment of the present invention, it is assumed that there are two image signal generators 110-1 and 110-2 for convenience of description. Then, when the display of the video signal of the first video signal generator 110-1 is determined, a low-level selected video control signal is input to the video signal multiplexer 120, and the second video signal generator 110-2 When the expression of the video signal of is determined, a high-level selection video control signal is input to the video signal multiplexer 120 as an example.

5 is an exemplary state diagram of an image output system according to an embodiment of the present invention.

As shown in FIG. 5, the video signal multiplexer 120 maintains a standby state when first driven. Even if the standby state is maintained, the video signal multiplexer 120 receives the first video signal and the second video signal generated by the first video signal generator 110-1 and the second video signal generator 110-2. do.

The video signal multiplexer 120 checks conditions of the selected video control signal and the video vertical synchronizing signal according to the input control signal. Then, a transition is made from the standby state to the image selection state or from the image selection state to the standby state.

That is, when a low-level selected video control signal is input to the video signal multiplexer 120 in a standby state and a rising edge of a vertical synchronization signal is input from the first video signal generator 110-1 (condition 1), the first Transition to the image selection state. In the first image selection state, the image signal multiplexer 120 transfers the first image signal received from the first image signal generator 110-1 to the LVDS transmitter 130.

At this time, in the first image selection state, when the selected image control signal is at a high level and the rising edge of the vertical synchronization signal is input from the first image signal generator 110-1 (condition 2), the image signal multiplexer 120 State transitions to the standby state. That is, it corresponds to the time when the displayed video content is changed by external control, and even if the rising edge of the vertical synchronization signal to the first video signal generator 110-1 is input, the first video signal is sent to the LVDS transmission unit ( 130) and maintains a standby state.

Then, when the rising edge of the vertical synchronization signal to the second video signal generator 110-2 is input while the high level selection video control signal is being input in the standby state (condition 3), the video signal multiplexer 120 transitions from the standby state to the second image selection state. The video signal multiplexer 120 transmits the second video signal transmitted from the second video signal generator 110-2 to the LVDS transmitter 130.

In the second image selection state, when the selected image control signal is at a high level and the rising edge of the vertical synchronization signal to the second image signal generator 110-2 is input (condition 4), the image signal multiplexer 120 State transitions to the standby state. Then, even though the rising edge of the vertical sync signal to the second video signal generator 110-2 is input, the second video signal is not transferred to the LVDS transmission unit 130 and remains in a standby state.

Operation timing of the video output system operating according to the above-described state diagram will be described with reference to FIG. 6 .

6 is an exemplary diagram illustrating operation timing of an image output system according to an embodiment of the present invention.

First, it is assumed that the video output system 100 is driven and transfers the first video signal to the video display device 30 . Then, as shown in FIG. 6 , the low-level selected video control signal is input to the video signal multiplexer 120 . At this time, when a rising edge is input to the first video vertical sync signal (①), the video signal multiplexer 120 transmits the frame of the first video received from the first video generator 110-1 to the LVDS transmitter 130. send to

When the frame for the first image is transmitted to the LVDS transmission unit 130, even if the selection image control signal for the second image, that is, the high-level selection image control signal is input to the image signal multiplexer 120 (②), The video signal multiplexer 120 transmits the first video signal to the LVDS transmitter 130 .

Conventionally, when a selection signal for the second image is received while the first image is being displayed, the first image and the second image may be simultaneously displayed or the screen may be pushed.

Therefore, even though the high-level selection video control signal is input, until the rising edge of the first video vertical synchronization signal for the first video is input, that is, until the frame being transmitted ends (③), After transmitting the frame to the LVDS transmitter 130, the video signal multiplexer 120 transitions from the first video selection state to the standby state (④). In the standby state, no video signal is output to the LVDS transmitter 130 even when the first video signal and the second video signal are input. However, in the image display device 30, frame 3 of the first image is continuously displayed.

Then, when the rising edge of the second video vertical synchronizing signal for the second video is input (⑤), the video signal multiplexer 120 transitions from the standby state to the second video selection state. The video signal multiplexer 120 transmits the second video signal to the LVDS transmitter 130 .

As described above, a method for the video output system 100 to change the video content displayed in the video display device 30 without errors will be described with reference to FIG. 7 .

In the embodiment of the present invention, for convenience of explanation, a case in which the first image is already output through the image display device 30 and the display image is changed to the second image will be described. Further, the first image selection signal for selecting the first image is a low level signal, and the second image selection signal for selecting the second image is a high level signal.

7 is a flowchart of a method of changing displayed video content according to an embodiment of the present invention.

As shown in FIG. 7, the video output system 100 starts in a standby state (S100). In the standby state, the video signal multiplexer 120 detects the rising edge of the vertical synchronization signal for each of all video signals generated by the video signal generators 110-1 and 110-2 and the video selection signal selected by the driver. Do (S101).

When the video signal multiplexer 120 is identically matched to the video vertical synchronization signal and the video selection signal, it transitions from a standby state to an image selection state in which a corresponding image is to be selected.

That is, the video signal multiplexer 120 determines whether the video vertical synchronization signal detected at the first time point in step S101 is the first video vertical synchronization signal (S102). If the video vertical synchronization signal is the first video vertical synchronization signal, the video signal multiplexer 120 receives the video selection signal (S103).

The video signal multiplexer 120 checks whether the video selection signal received in step S103 is the first video selection signal (S104), and if the second video selection signal is input, returns to step S100 and maintains a standby state. However, if the first image selection signal is input, the image signal multiplexer 120 transitions from the standby state to the first image selection state (S105).

When the transition is made to the first image selection state and the rising edge of the first image vertical sync signal is received (S106), the image signal multiplexer 120 repeats the steps from step S103.

Meanwhile, as a result of checking in step S102, if the second video vertical synchronizing signal is input, the video signal multiplexer 120 receives the video selection signal (S107). Then, the video signal multiplexer 120 checks whether the video selection signal received in step S107 is the second video selection signal (S108).

If the second image selection signal is input, the image signal multiplexer 120 returns to step S100 and maintains a standby state. However, if the second image selection signal is input, the image signal multiplexer 120 transitions from the standby state to the second image selection state (S109).

When the transition is made to the second image selection state and the rising edge of the second image vertical sync signal is received (S110), the image signal multiplexer 120 repeats the procedures from step S107.

As described above, the video output system 100 capable of changing the video output from the video display device 30 can be applied to various environments. For example, in an In-Vehicle Infotainment (IVI) system, when it is necessary to switch between video content generated inside a device, such as a multimedia or user interface (UI) screen, and video generated outside the device, such as a rear camera image, the present invention The video output system 100 described in the embodiment of can convert and provide an image without errors in the displayed image.

As another example, the video output system 100 described in the embodiment of the present invention when the processor detects that a screen freeze or an erroneous screen is output in a digital cluster system and converts to a warning screen can also be applied.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims are also included in the scope of the present invention. that fall within the scope of the right.

Claims (9)

A method of changing a display image output from an image output system operated by at least one processor to an image display device, the method comprising:
Receiving a first image signal and a second image signal while maintaining a standby state;
Based on the first image selection signal pre-selected at a first point in time and the received first image vertical sync signal, the first image selection state transitioned from the standby state is maintained and the received first image signal is transmitted to the image display device. The step of passing to
switching from the first image selection state to the standby state when a second image selection signal is received while the first image signal is transmitted;
Receiving a second video vertical synchronizing signal at a second time point while maintaining the standby state and switching from the standby state to the second image selection state when a rising edge of the second video vertical synchronization signal is input; and
Delivering the received second image to the image display device
Including, how to change the expression image. According to claim 1,
In the step of switching to the standby state,
When receiving a first video vertical synchronization signal for the first video signal between the first and second views, not transmitting the received first video to the video display device
Including, how to change the expression image. delete According to claim 1,
In the step of switching to the standby state,
Wherein the image display device outputs the first image transmitted at the first point in time. A video output system for outputting a video signal to a video display device,
According to a control signal from the outside, one of the first and second video selection signals is generated so that one of the first and second video signals is output to the video display device. a processor that
When initially driven, it maintains a standby state and switches from the standby state to an image selection state according to the video selection signal generated by the processor and the video vertical sync signal for each video signal, thereby selecting one of the first video signal or the second video signal. When one video signal is selected or when the image selection state is switched to the standby state, neither the first image signal nor the second image signal input is selected, and the second image signal is transmitted from the processor in the first image selection state. A video signal multiplexer that receives a selection signal and converts from the first video selection state to the standby state when receiving a first video vertical synchronizing signal from the first video generator; and
A transmitter for outputting a video signal selected from among the first video signal and the second video signal to the video display device.
Including, video output system. According to claim 5,
The video signal multiplexer,
When both the first video signal and the second video signal are received, the video selection signal is the first video selection signal and a first video vertical synchronization signal is received from the first video generator that generated the first video signal , A video output system that converts from the standby state to the first image selection state. delete According to claim 6,
The video signal multiplexer,
If a second video vertical synchronizing signal is received from the second image generator that generates the second image while maintaining the standby state, the standby state is switched to the second image selection state and the received second image is selected. , video output system. According to claim 8,
The first video signal generating unit for generating a first video signal composed of a plurality of first video frames to be output from the video display device and generating the first video vertical sync signal for each preset first video frame; and
The second video signal generator for generating a second video signal composed of a plurality of second video frames to be output from the video display device, and generating the second video vertical sync signal for each preset second video frame.
Including, video output system.

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