JP2016042114A - Image display device and image display control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the display of an image from being stopped only due to the fact that a change in a synchronization signal occurs by noise mixing with an input image signal or the like.SOLUTION: An image display device includes: reception means 105, 106 for receiving, from an external apparatus, an input image signal that is input via an input interface 104; image processing means 102 for generating an output image signal by applying image processing to the input image signal; and display means 107, 108 for displaying a display image corresponding to the output image signal. The reception means are able to switch between a first operation mode in which the input image signal can be transmitted to the image processing means and a second operation mode in which the input image signal is not transmitted to the image processing means depending on a result of communication with the external apparatus. The control means 103, 106 stop the display of the display image in response to detection of a change in the synchronization signal included in the input image signal and switching from the first operation mode to the second operation mode in the reception means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image display device that displays an image when an image signal is input from an external device.

  Examples of an image display device that is connected to an external device that outputs an image signal through a connector and displays an image corresponding to the input image signal include a projector and a direct-view display. In these image display devices, when the image signal is switched or the connector is inserted or removed in the image display state, the input of the image signal becomes unstable, and the display image is disturbed. For this reason, there has been proposed an image display device that monitors a synchronization signal included in an image signal and stops displaying an image when a change in the synchronization signal is detected. In Patent Document 1, at least one of the frequency and phase of the synchronization signal included in the input image signal is compared with at least one of the frequency and phase of the reference oscillation signal, and these mismatches are detected. In this case, an image display device that stops displaying an image is disclosed.

Japanese Patent Laid-Open No. 10-49093

  However, in the image display device disclosed in Patent Document 1, the frequency and phase of the synchronization signal included in the image signal are disturbed by noise such as static electricity mixed in the input image signal, and the image signal is switched. There is a possibility that it may be erroneously detected as a connector insertion or removal. Due to such erroneous detection, display of the image is unnecessarily stopped. Especially when a non-shielded non-shielded cable is used to connect the external device and the image display device, noise is likely to be mixed into the image signal input from the external device to the image display device. False detection is likely to occur.

  The present invention provides an image display apparatus and an image display program in which display of an image is not stopped only by a change in a synchronization signal caused by noise or the like in an input image signal.

  An image display device according to an aspect of the present invention includes: a receiving unit that receives an input image signal input from an external device through an input interface; and an image that generates an output image signal by performing image processing on the input image signal. A processing unit, a display unit for displaying a display image corresponding to the output image signal, a presence / absence of a change in a synchronization signal included in the input image signal, and detecting the display image by the display unit using the detection result It has a display and a control means for controlling its stop. The receiving means switches between the first operation mode in which the input image signal can be transmitted to the image processing means and the second operation mode in which the input image signal is not transmitted to the image processing means, according to the result of communication with the external device. Is possible. The control unit detects a change in the synchronization signal and stops displaying the display image in response to the reception unit switching from the first operation mode to the second operation mode.

  An image display control program according to another aspect of the present invention includes a receiving unit that receives an input image signal input from an external device through an input interface, and an output image by performing image processing on the input image signal. A computer of an image display device having an image processing means for generating a signal and a display means for displaying a display image corresponding to the output image signal, and detecting the presence or absence of a change in the synchronization signal included in the input image signal; This is a computer program for controlling the display of the display image by the display means and the stop thereof using the detection result. Switching between the first operation mode in which the receiving means can transmit the input image signal to the image processing means and the second operation mode in which the input image signal is not transmitted to the image processing means in accordance with the result of communication with the external device The computer detects the change of the synchronization signal and stops displaying the display image in response to the reception unit switching from the first operation mode to the second operation mode. Features.

  In the present invention, not only the change of the synchronization signal but also the display of the display image is stopped in response to the reception unit switching from the first operation mode to the second operation mode. For this reason, according to the present invention, the display of the output image is not stopped only by the change in the synchronization signal caused by the mixing of noise into the input image signal, that is, an image that can avoid unnecessary display stop of the display image. A display device can be realized.

1 is a block diagram illustrating a configuration of a projector that is an embodiment of the present invention. 6 is a flowchart showing the operation of the projector according to the embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows the configuration of a projector as an image display apparatus that is an embodiment of the present invention.

  The DVI interface 100 is connected to a DVI output device (not shown) capable of outputting a DVI image signal (video signal) as a first image signal via a connector, and the DVI image signal is output from the DVI output device. Input interface to be input. The DVI image signal (input image signal) input through the DVI interface 100 is received by the DVI signal receiving unit 101.

  The DVI signal receiving unit 101 converts the DVI image signal into digital image data that can be processed by the subsequent image signal processing unit 102, and outputs the digital image data to the image signal processing unit 102. The DVI signal receiving unit 101 has a function as a monitoring unit that monitors a synchronization signal included in the input DVI image signal, and outputs a monitoring result to the MPU 103 in response to a request from the MPU 103 described later. Specifically, the DVI signal receiving unit 101 monitors at least one of the period and phase of the synchronization signal and determines that the synchronization signal is stable if there is no change exceeding a predetermined level for a predetermined time. If the change exceeds a predetermined level, it is determined that the synchronization signal has changed. Then, this determination result (monitoring result) is output to the MPU 103.

  Instead of the DVI interface 100 or together with the DVI interface 100, an input interface corresponding to other image signals such as HDMI (registered trademark) and VGA may be provided. In this case, an image signal receiving unit corresponding to the input image signal may be provided.

  The HDBT interface 104 is connected to an HDBT output device (not shown) that is an external device capable of outputting an HDBT signal, which is a multiplexed signal corresponding to HDBaseT, which is a connection standard different from DVI, via a connector. This is an input interface to which an HDBT signal is input. The HDBT signal is a signal in which an image signal (video signal), a communication ETHER signal, a control signal, and the like are multiplexed. The HDBT signal input from the HDBT interface 104 is received by the HDBT signal receiving unit 105. The

  The HDBT signal receiving unit 105 decodes the HDBT signal into an image signal (input image signal as a second image signal: hereinafter referred to as an HDBT image signal), an ETHER signal, a control signal, and the like. Then, the HDBT image signal is output to the image signal receiving unit 106, and the ETHER signal and the control signal are output to the MPU 103, respectively. Further, the HDBT signal receiving unit 105 periodically communicates with the HDBT output device, and switches its operation mode according to the communication result. The communication result includes that communication is not possible. The operation modes of the HDBT signal receiving unit 105 include the following image transmission mode (first operation mode) and standby mode (second operation mode). The image transmission mode is an operation mode in which an HDBT image signal can be transmitted to the image signal processing unit 102 via the image signal receiving unit 106. The standby mode is an operation mode in which the HDBT image signal is not transmitted to the image signal receiving unit 106 (that is, the image signal processing unit 102).

  In the image transmission mode, when receiving a communication indicating that the HDBT image signal has been switched from the HDBT output device, the HDBT signal receiving unit 105 switches from the image transmission mode to the standby mode. In the image transmission mode, the HDBT signal receiving unit 105 also receives the image transmission result when the connector for connecting to the HDBT output device is disconnected from the HDBT interface 104 and communication with the HDBT output device is impossible. Switch from mode to standby mode.

  Note that the operation mode in which the image signal is not transmitted to the image signal processing unit 102 may be a mode other than the standby mode.

  Also, the HDBT signal receiving unit 105 outputs an operation mode change interrupt signal to the MPU 103 when switching its own operation mode. Further, the HDBT signal receiving unit 105 notifies the MPU 103 of its current operation mode in response to a request from the MPU 103.

  The image signal receiving unit 106 converts the HDBT image signal input from the HDBT signal receiving unit 105 into digital image data that can be processed by the subsequent image signal processing unit 102, and the digital image data is subjected to image signal processing. Output to the unit 102. The image signal receiving unit 106 has a function as a monitoring unit that monitors a synchronization signal included in the input HDBT image signal, and outputs a monitoring result to the MPU 103 in response to a request from the MPU 103. Specifically, the image signal receiving unit 106 monitors at least one of the cycle and phase of the synchronization signal, and determines that the synchronization signal is stable if there is no change exceeding a predetermined level for a predetermined time. If the change exceeds a predetermined level, it is determined that the synchronization signal has changed. Then, this determination result (monitoring result) is output to the MPU 103. The HDBT signal receiving unit 105 and the image signal receiving unit 106 constitute a receiving unit.

  The image signal processing unit 102 performs various image processing such as resolution conversion, keystone correction, brightness correction, contrast correction, and hue correction on the input digital image data, thereby displaying an image for display as an output image signal. Generate a signal.

  The display image signal output from the image signal processing unit 102 is output to the panel drive unit 107. Further, the image signal processing unit 102 switches display image signals to be output to the panel driving unit 107 in accordance with input switching control by the MPU 103. That is, any of the display image signals from the display image signal generated from the digital image data from the DVI signal receiving unit 101 and the display image signal generated from the digital image data from the image signal receiving unit 106 is displayed on the panel. Whether to output to the drive unit 107 is switched.

  The panel driving unit 107 drives the liquid crystal panel 108 as a light modulation element based on the input display image signal. The panel drive unit 107 and the liquid crystal panel 108 constitute display means. Instead of the liquid crystal panel 108, another light modulation element such as a digital micromirror device may be used.

  The lamp driving unit 109 controls lighting / extinguishing of the lamp 110 as a light source, and controls the power supplied to the lamp 110 to be constant.

  Light emitted from the lamp 110 is guided to the liquid crystal panel 108 and image modulation is performed by the liquid crystal panel 108. The image-modulated light is projected onto a projection surface such as a screen (not shown) by the projection lens 111. Thereby, the display image corresponding to the display image signal is displayed on the projection surface.

  The MPU 103 performs an operation corresponding to the input ETHER signal or control signal, or the operation signal input from the operation unit 112 according to the user operation. Further, the MPU 103 receives the monitoring result of the synchronization signal from the DVI signal receiving unit 101 and the image signal receiving unit 106, and detects the presence or absence of the change (at least one of the period and the phase) of the synchronization signal. The MPU 103 is configured by the function of the DVI signal receiving unit 101 and the image signal receiving unit 106 as the synchronization signal monitoring unit and the MPU 103.

  Further, the MPU 103 uses the detection result of the presence / absence of a change in the synchronization signal to display a display image display instruction (hereinafter referred to as a display instruction) and a display image display to the image signal processing unit 102. A command for stopping (hereinafter referred to as a display stop command) can be output. That is, it is possible to control display of the display image and its stop. Upon receiving the display command, the image signal processing unit 102 outputs a display image signal to the panel driving unit 107 to display a display image. On the other hand, the image signal processing unit 102 that has received the display stop command stops the display of the display image by stopping the output of the display image signal to the panel driving unit 107. At this time, the image signal processing unit 102 outputs to the panel driving unit 107 a specific image different from the display image, for example, an image signal corresponding to an all black image, and the specific image is applied instead of the display image. It may be displayed on the projection surface.

  Next, the operation of the projector (MPU 103) of the present embodiment will be described using the flowchart of FIG. The MPU 103 as a computer performs the following operation (processing) in accordance with an image display control program that is a computer program.

  In step (denoted as S in the figure) 100, the MPU 103 confirms the input switching control currently being performed on the image signal processing unit 102. That is, any of the display image signals from the display image signal generated from the digital image data from the DVI signal receiving unit 101 and the display image signal generated from the digital image data from the image signal receiving unit 106 is displayed on the panel. It is confirmed whether the drive unit 107 is outputting. If the MPU 103 causes the panel drive unit 107 to output the display image signal generated from the digital image data from the DVI signal receiving unit 101, the process proceeds to step 101. On the other hand, if the display image signal generated from the digital image data from the image signal receiving unit 106 is output to the panel driving unit 107, the process proceeds to step 105.

  In step 101, the MPU 103 starts time counting, and then proceeds to step 102.

  In step 102, the MPU 103 determines whether or not the predetermined time (for example, 200 milliseconds) described above has elapsed. If it has elapsed, the process proceeds to step 103. If not, the process returns to step 100.

  In step 103, the MPU 103 resets the time count.

  In step 104, the MPU 103 inquires of the DVI signal reception unit 101 about the monitoring result of the synchronization signal. When the monitoring result indicates that a change in the synchronization signal has occurred (when the MPU 103 detects a change in the synchronization signal), the MPU 103 proceeds to Step 109, and otherwise returns to Step 100.

  When the process proceeds from step 104 to step 109, the MPU 103 outputs a display stop command to the image signal processing unit 102, and stops the display of the display image. That is, when the MPU 103 detects that a change has occurred in the synchronization signal included in the DVI image signal (first image signal), the MPU 103 stops displaying the display image only by detecting the change in the synchronization signal. Let

  On the other hand, in step 105, the MPU 103 confirms the operation mode of the HDBT signal receiving unit 105. In step 106, the MPU 103 proceeds to step 107 if the operation mode of the HDBT signal receiving unit 105 is the image transmission mode, and returns to step 100 if the operation mode is the standby mode.

  In step 107, the MPU 103 confirms whether or not an operation mode change interrupt signal indicating switching from the image transmission mode to the standby mode has occurred. If it has occurred, go to Step 108; otherwise, go back to Step 100.

  In step 108, the MPU 103 inquires of the image signal receiving unit 106 about the monitoring result of the synchronization signal. When the monitoring result indicates that a change in the synchronization signal has occurred (when the MPU 103 detects a change in the synchronization signal), the MPU 103 proceeds to Step 109, and otherwise returns to Step 100.

  When the process proceeds from step 108 to step 109, the MPU 103 outputs a display stop command to the image signal processing unit 102 and stops the display of the display image. In other words, when the MPU 103 detects that a change has occurred in the synchronization signal included in the HDBT image signal (second image signal), the MPU 103 not only detects the change in the synchronization signal but also changes from the image transmission mode to the standby mode. The display of the display image is stopped according to the switching of. When both the change of the synchronization signal and the switching from the image transmission mode to the standby mode occur, the input image signal is switched as described above, and the connector for connecting to the HDBT output device is disconnected from the HDBT interface 104 (disconnected). Or). Therefore, display of the display image is stopped according to both the change of the synchronization signal and the switching from the image transmission mode to the standby mode, so that unnecessary display of the display image due to noise mixing in the input image signal is performed. Stops can be avoided. This is particularly effective when a non-shielded cable that easily causes noise mixing is used for connection between the HDBT interface 104 and the HDBT output device.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

102 Image signal processing unit 103 MPU
104 HDBT interface 105 HDBT signal receiver 106 Image signal receiver

Claims (6)

Receiving means for receiving an input image signal input from an external device through an input interface;
Image processing means for generating an output image signal by performing image processing on the input image signal;
Display means for displaying a display image corresponding to the output image signal;
Detecting the presence or absence of a change in the synchronization signal included in the input image signal, and using the result of the detection, the display means by the display means and control means for controlling the stop,
The receiving unit is configured to transmit a first operation mode in which the input image signal can be transmitted to the image processing unit and a second mode in which the input image signal is not transmitted to the image processing unit in accordance with a result of communication with the external device. It is possible to switch to the operation mode of
The control means detects a change in the synchronization signal and stops displaying the display image in response to the receiving means switching from the first operation mode to the second operation mode. A characteristic image display device.   The image display device according to claim 1, wherein when the display of the display image is stopped, the control unit causes the display unit to display a specific image different from the display image.   The control means detects a change in the synchronization signal when the external device and the input interface are connected by a non-shielded cable, and the receiving means starts the second operation from the first operation mode. 3. The image display device according to claim 1, wherein display of the display image is stopped in response to switching to an operation mode.   4. The image display according to claim 1, wherein the input image signal is input from the external device through the input interface as a multiplexed signal that is multiplexed with at least a communication signal. 5. apparatus. The control means determines whether the input image signal is a first image signal or a second image signal having different connection standards,
When the input image signal is a first image signal, the display of the display image is stopped in response to detecting a change in the synchronization signal,
When the input image signal is a second image signal, a change in the synchronization signal is detected, and the receiving unit is switched from the first operation mode to the second operation mode. The image display apparatus according to claim 1, wherein display of the display image is stopped. A receiving unit that receives an input image signal input from an external device through an input interface, an image processing unit that generates an output image signal by performing image processing on the input image signal, and the output image signal A computer of an image display device having display means for displaying a display image;
Detecting the presence or absence of a change in the synchronization signal included in the input image signal;
A computer program for controlling display of the display image by the display means and stop thereof using the detection result,
A first operation mode in which the receiving means can transmit the input image signal to the image processing means in accordance with a result of communication with the external device; and a second that does not transmit the input image signal to the image processing means. When switching to the operation mode is possible,
The computer detects a change in the synchronization signal and stops displaying the display image in response to the reception unit switching from the first operation mode to the second operation mode. An image display control program.