Display control method and display device

Abstract

The present application provides display control method and display device. The problem that the reproduction of the image is performed in the state that the deviation remains when the image signals input to the plurality of projectors respectively have a deviation of one frame or more between the projectors is solved. The display control method includes: acquiring a standard time; synchronizing an internal time referred to in the processing of one display device (10-1) with the standard time; detecting an internal time, that is, a reference time, when the image represented by the input image signal satisfies a prescribed condition; outputting the reference time to other display devices (10-2) among the plurality of display devices; acquiring the reference time detected in the other display devices (10-2); and delaying the vertical synchronization signal by a time from the reference time of one display device (10-1) to the reference time of the other display devices (10-2) when the reference time of the other display devices (10-2) is later than the reference time of one display device (10-1).

Description

Technical Field

[0001] This invention relates to display control methods and display devices. Background Technology

[0002] Previously known technologies involved multiple projection, which used multiple projectors to display a single image. However, in multiple projection scenarios, where multiple image output devices output images to their corresponding projectors (one-to-one), the vertical synchronization signals from each output device to the projector are typically not synchronized. This results in display discrepancies between the multiple projectors.

[0003] In addition, when multiple projectors reproduce a single image using the content reproduction function of each projector, display discrepancies sometimes occur between the projectors because the vertical synchronization signals generated within each projector are not synchronized.

[0004] Regarding the synchronization of vertical synchronization signals between projectors, Patent Document 1 discloses a technique for synchronizing displays across multiple projectors. Specifically, in the invention of Patent Document 1, multiple projectors initially synchronize internal times referenced during each operation. Next, based on the synchronized internal times, the multiple projectors synchronize the phases of the reference vertical synchronization signals among themselves. Finally, each projector synchronizes the phase of its display vertical synchronization signal with the phase of the nearest reference vertical synchronization signal. As a result, the phases of the display vertical synchronization signals are the same across the multiple projectors, achieving display synchronization among them.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-49544 Summary of the Invention

[0006] However, in the technology of Patent Document 1, the initial deviation between the phase of the displayed vertical synchronization signal and the phase of the reference vertical synchronization signal converges to within one frame of the image frame displayed by the projector. Therefore, in the technology of Patent Document 1, the range of phase adjustment is at most one frame. That is, there is a problem that when the image signals input to multiple projectors themselves have a deviation of more than one frame between the projectors, the technology of Patent Document 1 cannot address this, resulting in image reproduction with residual deviation.

[0007] One aspect of the present invention is a display control method for controlling one of the plurality of display devices in a system that synchronizes images displayed through a plurality of display devices. The method includes: acquiring a standard time; synchronizing an internal time referenced in the processing of the one display device with the standard time; detecting a reference time, wherein the reference time is an internal time when the image represented by the input image signal satisfies predetermined conditions; outputting the reference time to other display devices among the plurality of display devices; acquiring the reference time detected in the other display devices; if the reference time of the other display devices is later than the reference time of the one display device, delaying a vertical synchronization signal by a time from the reference time of the one display device to the reference time of the other display devices; and using the delayed vertical synchronization signal to display the image represented by the input image signal.

[0008] Furthermore, one aspect of the present invention is a display control method for controlling one of the plurality of display devices in a system that synchronizes images displayed through a plurality of display devices, comprising: obtaining a standard time; synchronizing an internal time referenced in the processing of the one display device with the standard time; measuring a reference time, wherein the reference time is the time from the internal time reaching a first time to the initial generation of a vertical synchronization signal; outputting the reference time to the other display devices among the plurality of display devices; obtaining the reference time from the other display devices; if the reference time of the other display devices is longer than the reference time of the one display device, delaying the vertical synchronization signal by the difference between the reference time of the one display device and the reference time of the other display devices; and using the delayed vertical synchronization signal to display an image represented by an input image signal.

[0009] Furthermore, one aspect of the present invention is a display device among a plurality of display devices in a system for synchronizing images displayed on a plurality of display devices, comprising: a first acquisition unit that acquires a standard time; a synchronization unit that synchronizes an internal time referenced in the processing of the first display device with the standard time; a detection unit that detects a reference time, the reference time being an internal time in which the image represented by the input image signal satisfies predetermined conditions; an output unit that outputs the reference time to the other display devices among the plurality of display devices; a second acquisition unit that acquires the reference time detected in the other display devices; a delay unit that, when the reference time of the other display devices is later than the reference time of the first display device, delays the vertical synchronization signal by a time from the reference time of the first display device to the reference time of the other display devices; and a display control unit that uses the delayed vertical synchronization signal to display the image represented by the input image signal.

[0010] Furthermore, one aspect of the present invention is a display device among a plurality of display devices in a system for synchronizing images displayed by a plurality of display devices, comprising: a first acquisition unit that acquires a standard time; a synchronization unit that synchronizes an internal time referenced in the processing of the first display device with the standard time; a measurement unit that measures a reference time, the reference time being the time from the internal time to a first time until the initial generation of a vertical synchronization signal; an output unit that outputs the reference time to the other display devices among the plurality of display devices; a second acquisition unit that acquires the reference time from the other display devices; a delay unit that, when the reference time of the other display devices is longer than the reference time of the first display device, delays the vertical synchronization signal by the difference between the reference time of the first display device and the reference time of the other display devices; and a display control unit that uses the delayed vertical synchronization signal to display an image represented by an input image signal. Attached Figure Description

[0011] Figure 1 This is a block diagram showing the structure of the display control system 1 according to the first embodiment.

[0012] Figure 2 This is a block diagram showing the structure of the first projector 10-1 according to the first embodiment.

[0013] Figure 3 This is a functional block diagram showing the structure of the information acquisition unit 122.

[0014] Figure 4 This is a block diagram showing the structure of the first image output device 20-1 according to the first embodiment.

[0015] Figure 5 This is a timing diagram showing the operation of the display control system 1 according to the first embodiment.

[0016] Figure 6 This is a block diagram showing the structure of the first projector 10A-1 according to the second embodiment.

[0017] Figure 7 This is a functional block diagram of the information acquisition unit 122A.

[0018] Figure 8 This is a timing diagram showing the operation of the display control system 1A according to the second embodiment.

[0019] Label Explanation

[0020] 1, 1A: Display control system; 10-1, 10A-1: First projector; 10-2, 10A-2: Second projector; 20-1: First image output device; 20-2: Second image output device; 30: Time server; 110: Projection device; 120, 120A: Processing device; 121: Signal acquisition unit; 122, 122A: Information acquisition unit; 122-1: First acquisition unit; 122-2, 122A-2: Second acquisition unit; 123: Synchronization unit; 124: Detection unit; 125, 125A: Output unit; 126, 126A: Delay unit; 127: Display control unit; 128: Measurement unit; 130, 130A: Storage device; 140: Communication device; 150: Interface circuit; 210: Processing device; 211: Image acquisition unit; 212: Signal output unit; 220: Storage device; 230: Interface circuit; P: Image; P1: First image; P2: Second image; PR1, PR1A, PR2: Control program. Detailed Implementation

[0021] Hereinafter, the display control method and display device of the embodiments will be described with reference to the accompanying drawings. Furthermore, in the drawings, the dimensions and scales of each part are appropriately different from the actual dimensions and scales. Additionally, the embodiments described below are preferred examples, and therefore various technically preferred limitations have been added; however, unless the scope of this disclosure is specifically limited in the following description, the scope of this disclosure is not limited to these embodiments.

[0022] 1: First Implementation Method

[0023] 1-1: Structure of the Implementation Method

[0024] 1-1-1: Overall Structure

[0025] Figure 1 This is a block diagram showing the configuration of the display control system 1 according to the first embodiment. The display control system 1 performs multi-projection using multiple projectors.

[0026] The display control system 1 includes a first projector 10-1 that projects a first image P1 and a second projector 10-2 that projects a second image P2, serving as a projector that projects images onto a flat surface such as a screen or wall. The first image P1 and the second image P2 constitute one image P. Furthermore, in this specification, the first projector 10-1 is an example of a "first display device," and the second projector 10-2 is an example of a "second display device." In general, both the first projector 10-1 and the second projector 10-2 are examples of "display devices."

[0027] In addition, the first projector 10-1 and the second projector 10-2 can be configured to project onto separate projection surfaces on a wall or screen, or they can be configured to be in contact, or they can be configured to share a common area.

[0028] Furthermore, as an example, the display control system 1 includes two projectors: a first projector 10-1 and a second projector 10-2. However, the display control system 1 can have any number of projectors.

[0029] Furthermore, the display control system 1 includes a first image output device 20-1 and a second image output device 20-2. The first image output device 20-1 is connected to the first projector 10-1 in a communicable manner, for example, via an HDMI (High Definition Multimedia Interface) cable. Similarly, the second image output device 20-2 is connected to the second projector 10-2 in a communicable manner, for example, via an HDMI cable.

[0030] "HDMI" is a registered trademark.

[0031] A first input image signal, which forms the basis of the first image P1, is input from the first image output device 20-1 to the first projector 10-1. Similarly, a second input image signal, which forms the basis of the second image P2, is input from the second image output device 20-2 to the second projector 10-2.

[0032] The first frame of the first input image signal corresponds to the first frame of the second input image signal. Similarly, the nth frame of the first input image signal corresponds to the nth frame of the second input image signal. Here, n is a natural number.

[0033] Furthermore, a first input vertical synchronization signal is input from the first image output device 20-1 to the first projector 10-1. Similarly, a second input vertical synchronization signal is input from the second image output device 20-2 to the second projector 10-2. These first input vertical synchronization signals and second input vertical synchronization signals are not synchronized. As a result, the first input image signal and the second input image signal are not synchronized. In other words, a discrepancy occurs between the time when the first input image signal is input to the first projector 10-1 at the nth frame and the time when the second input image signal is input to the second projector 10-2 at the nth frame.

[0034] Here, "first input vertical synchronization signal" and "second input vertical synchronization signal" are examples of vertical synchronization signals.

[0035] In addition, the display control system 1 includes a time server 30. The time server 30 keeps time for a standard time, which serves as the standard in the display control system 1.

[0036] like Figure 1 As shown, the first projector 10-1, the second projector 10-2, and the time server 30 are connected to each other via a communication network NET in a manner that enables them to communicate with each other. The time server 30 provides standard time information to the first projector 10-1 and the second projector 10-2 via the communication network NET.

[0037] 1-1-2: Structure of the first projector 10-1

[0038] Figure 2 This is a block diagram illustrating the structure of a first projector 10-1 according to a first embodiment. The first projector 10-1 includes a projection device 110, a processing device 120, a storage device 130, a communication device 140, and an interface circuit 150. The components of the first projector 10-1 are interconnected via one or more buses for communication of information. Furthermore, the components of the first projector 10-1 may be composed of one or more devices; some components of the first projector 10-1 are omitted. Additionally, the structure of the second projector 10-2 is essentially the same as that of the first projector 10-1.

[0039] The projection device 110 is a device that projects a first image P1 onto a flat surface such as a screen or a wall based on a first input image signal obtained from the display control unit 127 (described later). The projection device 110 includes, for example, a light source, a liquid crystal panel, and a projection lens. The liquid crystal panel modulates the light from the light source, and the modulated light is projected onto a flat surface such as a screen or a wall via the projection lens.

[0040] The processing device 120 is a processor that controls the entire first projector 10-1, and may be composed of one or more chips. The processing device 120 may be, for example, a central processing unit (CPU) including interfaces with peripheral devices, arithmetic units, and registers. Alternatively, some or all of the functions of the processing device 120 may be implemented using hardware such as a DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), or FPGA (Field Programmable Gate Array). The processing device 120 executes various processes in parallel or sequentially.

[0041] Storage device 130 is a recording medium that can be read by processing device 120, storing multiple programs including control program PR1 executed by processing device 120. Additionally, control program PR1 can also be sent from other devices, such as a server managing the first projector 10-1, via a communication network not shown. Storage device 130 may be composed of at least one of ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and RAM (Random Access Memory). Storage device 130 may also be referred to as a register, cache, main memory, or main storage device.

[0042] The communication device 140 is hardware used for communicating with other devices, serving as a transceiver. Specifically, in this embodiment, the communication device 140 is a communication device used to connect the first projector 10-1 to the time server 30 via wired or wireless means. The communication device 140 is also referred to, for example, as a network device, network controller, network interface card (NIC), or communication module.

[0043] Interface circuit 150 is an interface that connects to the first image output device 20-1 in a communicative manner. For example, interface circuit 150 is an interface such as USB (Universal Serial Bus) or HDMI (High Definition Multimedia Interface). "USB" is a registered trademark. Interface circuit 150 has the function of sending various information and signals to the first image output device 20-1 and receiving various information and signals from the first image output device 20-1.

[0044] The processing unit 120 reads and executes the control program PR1 from the storage device 130, and functions as a signal acquisition unit 121, an information acquisition unit 122, a synchronization unit 123, a detection unit 124, an output unit 125, a delay unit 126, and a display control unit 127.

[0045] The signal acquisition unit 121 acquires the first input image signal and the first input vertical synchronization signal from the first image output device 20-1 via the interface circuit 150.

[0046] The information acquisition unit 122 acquires various information from external devices of the first projector 10-1. Figure 3 This is a functional block diagram showing the structure of the information acquisition unit 122. The information acquisition unit 122 has a first acquisition unit 122-1 and a second acquisition unit 122-2.

[0047] The first acquisition unit 122-1 obtains the standard time from the time server 30 via the communication device 140.

[0048] The second acquisition unit 122-2 acquires the reference time (described later) from the second projector 10-2 via the communication device 140. The functions of the second acquisition unit 122-2 will be explained in detail later.

[0049] return Figure 2 As explained, the synchronization unit 123 synchronizes the internal time referenced during the processing of the first projector 10-1 with the standard time acquired by the first acquisition unit 122-1. The synchronization unit 123 synchronizes the internal time with the standard time, for example, by using a known protocol technology such as PTP (Precision Time Protocol) or NTP (Network Time Protocol).

[0050] Furthermore, the synchronization unit 123 of the second projector 10-2 also synchronizes the internal time referenced in the processing of the second projector 10-2 with the standard time. As a result, the internal time of the first projector 10-1 and the internal time of the second projector 10-2 are both synchronized with the standard time.

[0051] The detection unit 124 detects the reference time, which is the internal time when the image represented by the input image signal acquired by the signal acquisition unit 121 meets the specified conditions.

[0052] Here, the "prescribed conditions" could be, for example, the image represented by the input image signal switching from a first input image to a second input image. Furthermore, the first input image could be, for example, a raster image whose entire surface is red, and the second input image could be, for example, a raster image whose entire surface is green. As an example, by using two images with high contrast as the first and second input images respectively, the detection unit 124 can easily detect the switching of the image represented by the input image signal from the first input image to the second input image. In this case, the detection unit 124 uses the internal time when it detects the switching of the image represented by the input image signal from the first input image to the second input image as a reference time.

[0053] As a result, the detection unit 124 is able to detect synchronization deviations in the input image signals between the first projector 10-1 and the second projector 10-2. In particular, by using raster images with high contrast as the first and second input images, for example, the detection unit 124 can detect synchronization deviations in the input image signals more reliably.

[0054] Alternatively, the "prescribed condition" could be, for example, that the image represented by the input image signal contains a prescribed image. More specifically, the area displayed by the first projector 10-1 has an effective area visible to the user and an invalid area located outside the effective area and invisible to the user. The prescribed image represented by the input image signal is displayed in the invalid area, not in the effective area. As a result, the user will not see the prescribed image. The prescribed image may, for example, contain at least one of prescribed text and symbols. In this case, the detection unit 124 detects the internal time when it detects that the image represented by the input image signal contains at least one of the prescribed text and symbols as an invalid area, as a reference time.

[0055] More specifically, the liquid crystal panel of the projection device 110 has a first region corresponding to the aforementioned effective region and a second region corresponding to the aforementioned ineffective region. Similarly, the image represented by the input image signal may, for example, include at least one of a specified text or symbol as a specified image displayed in the second region but not displayed in the first region.

[0056] As a result, the detection unit 124 is able to detect the synchronization deviation of the input image signals between the first projector 10-1 and the second projector 10-2. In particular, by basing the detection on the presence or absence of a specified image, the detection unit 124 can detect the synchronization deviation of the input image signals more reliably.

[0057] Furthermore, by displaying a predetermined image between the first projector 10-1 and the second projector 10-2, used to detect the synchronization deviation of the input image signal, in an invalid area that is out of the user's sight, the user will not notice the presence or absence of the predetermined image and will be able to appreciate the image represented by the input image signal.

[0058] The output unit 125 outputs the reference time detected by the detection unit 124 to the second projector 10-2 via the communication device 140. Similarly, the output unit 125 of the second projector 10-2 also outputs the reference time detected by the detection unit 124 to the first projector 10-1 via the communication device 140. In this specification, the reference time detected by the first projector 10-1 is referred to as the "first reference time," and the reference time detected by the second projector 10-2 is referred to as the "second reference time."

[0059] Here, as described above, the second acquisition unit 122-2 acquires the second reference time from the second projector 10-2 via the communication device 140. Similarly, the second acquisition unit 122-2 of the second projector 10-2 also acquires the first reference time from the first projector 10-1 via the communication device 140.

[0060] In other words, the first projector 10-1 and the second projector 10-2 notify each other of the reference time they have detected.

[0061] When the second reference time obtained from the second projector 10-2 is later than the first reference time, the delay unit 126 delays the first input vertical synchronization signal obtained by the signal acquisition unit 121 by the time from the first reference time to the second reference time. On the other hand, when the second reference time obtained from the second projector 10-2 is the same as or earlier than the first reference time, the delay unit 126 does not perform any processing on the first input vertical synchronization signal.

[0062] Similarly, the delay unit 126 of the second projector 10-2 delays the second input vertical synchronization signal acquired by the signal acquisition unit 121 from the second reference time to the first reference time when the first reference time obtained from the first projector 10-1 is later than the second reference time. On the other hand, the delay unit 126 of the second projector 10-2 does not process the second input vertical synchronization signal when the first reference time obtained from the first projector 10-1 is the same as or earlier than the second reference time.

[0063] When the second reference time is later than the first reference time, the display control unit 127 outputs the first input image signal to the projection device 110 using the first input vertical synchronization signal delayed by the delay unit 126. That is, the display control unit 127 uses the delayed first input vertical synchronization signal to display the first image P1 represented by the first input image signal. On the other hand, when the second reference time is the same as or earlier than the first reference time, the display control unit 127 outputs the first input image signal to the projection device 110 using the first input vertical synchronization signal not processed by the delay unit 126. That is, the display control unit 127 uses the first input vertical synchronization signal not processed by the delay unit 126 to display the first image P1 represented by the first input image signal.

[0064] Similarly, the display control unit 127 of the second projector 10-2, when the first reference time is later than the second reference time, outputs the second input image signal to the projection device 110 using the second input vertical synchronization signal delayed by the delay unit 126. That is, the display control unit 127 of the second projector 10-2 uses the delayed second input vertical synchronization signal to display the second image P2 represented by the second input image signal. On the other hand, when the first reference time is the same as or earlier than the second reference time, the display control unit 127 of the second projector 10-2 outputs the second input image signal to the projection device 110 using the second input vertical synchronization signal not processed by the delay unit 126. That is, the display control unit 127 of the second projector 10-2 uses the second input vertical synchronization signal not processed by the delay unit 126 to display the second image P2 represented by the second input image signal.

[0065] As a result, the first projector 10-1 can solve the problem of reproducing images with residual deviations when the image signals input to multiple projectors themselves have a deviation of more than one frame between the projectors. In particular, the first projector 10-1 can solve the problem caused by the deviation in the synchronization of the input image signals, which cannot be solved by simply synchronizing the internal times of the multiple projectors.

[0066] 1-1-3: Structure of the first image output device 20-1

[0067] Figure 4This is a block diagram illustrating the structure of the first image output device 20-1 according to the first embodiment. The first image output device 20-1 includes a processing unit 210, a storage unit 220, and an interface circuit 230. The components of the first image output device 20-1 are interconnected via one or more buses for information communication. Alternatively, the components of the first image output device 20-1 may be composed of one or more devices, thus omitting some components of the first image output device 20-1. Furthermore, the structure of the second image output device 20-2 is essentially the same as that of the first image output device 20-1.

[0068] The processing unit 210 is a processor that controls the entire first image output device 20-1, and may be composed of one or more chips. The processing unit 210 may be, for example, a central processing unit (CPU) including interfaces with peripheral devices, arithmetic units, and registers. Alternatively, some or all of the functions of the processing unit 210 may be implemented using hardware such as a DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), or FPGA (Field Programmable Gate Array). The processing unit 210 executes various processes in parallel or sequentially.

[0069] Storage device 220 is a recording medium that processing device 210 can read, storing multiple programs including control program PR2 executed by processing device 210. Furthermore, control program PR2 can also be sent from other devices such as a server managing the first image output device 20-1 via a communication network not shown. Storage device 220 can also store image information representing the first image P1. Storage device 220 can be configured with at least one of, for example, ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and RAM (Random Access Memory). Storage device 220 can also be referred to as a register, cache, main memory, or main storage device.

[0070] Interface circuit 230 is an interface that connects to the first projector 10-1 in a communicative manner. For example, interface circuit 230 is an interface such as USB (Universal Serial Bus) or HDMI (High Definition Multimedia Interface). Interface circuit 230 has the function of sending various information and signals to the first projector 10-1, and the function of receiving various information and signals from the first projector 10-1.

[0071] The processing unit 210 reads and executes the control program PR2 from the storage device 220, and functions as the image acquisition unit 211 and the signal output unit 212.

[0072] The image acquisition unit 211 acquires image information representing an image from an external device or storage device 220 of the first image output device 20-1. In particular, the image acquisition unit 211 acquires image information representing the first image P1.

[0073] In addition, the image acquisition unit 211 of the second image output device 20-2 also acquires image information representing the second image P2.

[0074] Based on the image information acquired by the image acquisition unit 211, the signal output unit 212 generates a first input image signal for use in the first projector 10-1, and outputs the first input image signal to the first projector 10-1 via the interface circuit 230. In addition, the signal output unit 212 outputs the aforementioned first input vertical synchronization signal to the first projector 10-1 via the interface circuit 230.

[0075] In addition, the signal output unit 212 of the second image output device 20-2 also outputs the second input image signal and the second input vertical synchronization signal to the second projector 10-2 via the interface circuit 230.

[0076] 1-2: Actions of the implementation method

[0077] Figure 5 This is a timing diagram illustrating the operation of the display control system 1 according to the first embodiment. Hereinafter, refer to... Figure 5 The operation of the display control system 1 will be explained.

[0078] In step S1, the processing unit 120 of the first projector 10-1 functions as the first acquisition unit 122-1. The processing unit 120 acquires the standard time from the time server 30.

[0079] In step S2, the processing unit 120 of the second projector 10-2 functions as the first acquisition unit 122-1. This processing unit 120 acquires the standard time from the time server 30.

[0080] In step S3, the processing device 120 of the first projector 10-1 functions as a synchronization unit 123. This processing device 120 synchronizes the internal time referenced in the processing of the first projector 10-1 with the standard time obtained in step S1.

[0081] In step S4, the processing device 120 of the second projector 10-2 functions as a synchronization unit 123. This processing device 120 synchronizes the internal time referenced in the processing of the second projector 10-2 with the standard time obtained in step S2.

[0082] In step S5, the processing unit 120 of the first projector 10-1 functions as a detection unit 124. The processing unit 120 detects the internal time, i.e., the first reference time, when the image represented by the first input image signal meets the predetermined conditions.

[0083] In step S6, the processing unit 120 of the second projector 10-2 functions as a detection unit 124. This processing unit 120 detects the internal time, i.e., the second reference time, when the image represented by the second input image signal meets the predetermined conditions.

[0084] In step S7, the processing unit 120 of the first projector 10-1 functions as an output unit 125. The processing unit 120 of the first projector 10-1 outputs the first reference time detected in step S5 to the second projector 10-2. Furthermore, the processing unit 120 of the second projector 10-2 functions as a second acquisition unit 122-2. The processing unit 120 of the second projector 10-2 acquires the first reference time from the first projector 10-1.

[0085] In step S8, the processing unit 120 of the second projector 10-2 functions as an output unit 125. The processing unit 120 of the second projector 10-2 outputs the second reference time detected in step S6 to the first projector 10-1. Furthermore, the processing unit 120 of the first projector 10-1 functions as a second acquisition unit 122-2. The processing unit 120 of the first projector 10-1 acquires the second reference time from the second projector 10-2.

[0086] In step S9, the processing unit 120 of the first projector 10-1 functions as a delay unit 126. This processing unit 120 compares the first reference time detected by itself with the second reference time obtained from the second projector 10-2. If the second reference time is later than the first reference time, i.e., if the determination result in step S9 is positive, the processing unit 120 executes the processing in step S10. On the other hand, if the second reference time is the same as or earlier than the first reference time, i.e., if the determination result in step S9 is negative, the processing unit 120 executes the processing in step S13.

[0087] In step S10, the processing device 120 of the first projector 10-1 functions as a delay unit 126. This processing device 120 delays the first input vertical synchronization signal from the first reference time to the second reference time.

[0088] In step S11, the processing unit 120 of the second projector 10-2 functions as a delay unit 126. This processing unit 120 compares the second reference time detected by itself with the first reference time obtained from the first projector 10-1. If the first reference time is later than the second reference time, i.e., if the determination result in step S11 is positive, the processing unit 120 executes the processing in step S12. On the other hand, if the first reference time is the same as or earlier than the second reference time, i.e., if the determination result in step S11 is negative, the processing unit 120 executes the processing in step S14.

[0089] In step S12, the processing device 120 of the second projector 10-2 functions as a delay unit 126. This processing device 120 delays the second input vertical synchronization signal from the second reference time to the first reference time.

[0090] In step S13, the processing device 120 of the first projector 10-1 functions as a display control unit 127. The processing device 120 uses the first input vertical synchronization signal to display the first image P1 represented by the first input image signal.

[0091] In step S14, the processing device 120 of the second projector 10-2 functions as a display control unit 127. This processing device 120 uses the second input vertical synchronization signal to display the second image P2 represented by the second input image signal.

[0092] 1-3: Effects of the Implementation Method

[0093] The display control method of this embodiment is a display control method for controlling a first projector 10-1, which is one of the multiple display devices, in a display control system 1 that synchronizes images displayed through multiple display devices. The display control method includes: acquiring a standard time; synchronizing an internal time referenced in the processing of the first projector 10-1 with the standard time; detecting a first reference time, which is an internal time when the image represented by the first input image signal meets predetermined conditions; outputting the first reference time to a second projector 10-2, which is another display device among the multiple display devices; acquiring a second reference time detected in the second projector 10-2; if the second reference time of the second projector 10-2 is later than the first reference time of the first projector 10-1, delaying the first input vertical synchronization signal by the time from the first reference time of the first projector 10-1 to the second reference time of the second projector 10-2; and displaying the image represented by the first input image signal using the delayed first input vertical synchronization signal.

[0094] The aforementioned display control method addresses the problem that when the image signals input to multiple projectors exhibit a deviation of more than one frame between the projectors, image reproduction occurs while still exhibiting this deviation. Furthermore, the aforementioned display control method resolves the issue caused by synchronization deviations in the input image signals, a problem that cannot be solved solely by synchronizing the internal timing of the multiple projectors.

[0095] Furthermore, in the above-described display control method, the aforementioned condition is that the image represented by the input image signal is switched from the first input image to the second input image.

[0096] By switching the image represented by the input image signal from the first input image to the second input image as specified above, the first projector 10-1 can detect the synchronization deviation of the input image signals between the first projector 10-1 and the second projector 10-2. In particular, for example, by using raster images with high contrast to each other as the first and second input images, the first projector 10-1 can detect the synchronization deviation of the input image signals more reliably.

[0097] Furthermore, in the above-described display control method, the aforementioned condition is that the image represented by the input image signal contains a specified image.

[0098] By using the condition that the image represented by the input image signal contains a specified image as described above, the first projector 10-1 can detect the synchronization deviation of the input image signal between the first projector 10-1 and the second projector 10-2. In particular, by basing the detection of the synchronization deviation of the input image signal on the presence or absence of the specified image, the first projector 10-1 can detect the synchronization deviation of the input image signal more reliably.

[0099] Furthermore, in the above-described display control method, the image represented by the input image signal is displayed through the first projector 10-1. The area displayed by the first projector 10-1 includes: an effective area, which is visible to the user; and an ineffective area, which is located outside the effective area and is not visible to the user. The aforementioned specified image is displayed in the ineffective area and not in the effective area.

[0100] By displaying a predetermined image between the first projector 10-1 and the second projector 10-2, used to detect the synchronization deviation of the input image signal, in an invalid area that is out of the user's sight, the user will not notice the presence or absence of the predetermined image and can appreciate the image represented by the input image signal.

[0101] The display device in this embodiment is a first projector 10-1, which is one of the display devices in a display control system 1 that synchronizes images displayed on multiple display devices. The first projector 10-1 includes a first acquisition unit 122-1, a synchronization unit 123, a detection unit 124, an output unit 125, a second acquisition unit 122-2, a delay unit 126, and a display control unit 127. The first acquisition unit 122-1 acquires a standard time. The synchronization unit 123 synchronizes the internal time referenced in the processing of the first projector 10-1 with the standard time. The detection unit 124 detects the internal time, i.e., the first reference time, when the image represented by the first input image signal meets predetermined conditions. The output unit 125 outputs the first reference time to the second projector 10-2, which is another display device among the multiple display devices. The second acquisition unit 122-2 acquires the second reference time detected in the second projector 10-2. If the second reference time is later than the first reference time, the delay unit 126 delays the first input vertical synchronization signal by the time from the first reference time to the second reference time. The display control unit 127 uses the delayed first input vertical synchronization signal to display the image represented by the first input image signal.

[0102] The first projector 10-1, as the aforementioned display device, solves the problem that when the image signals input to multiple projectors have a deviation of more than one frame between the projectors, the image is reproduced in a state with residual deviation. In particular, the first projector 10-1 solves the problem caused by the deviation in the synchronization of the input image signals, which cannot be solved by simply synchronizing the internal timing between the multiple projectors.

[0103] 2: Second Implementation Method

[0104] 2-1: Structure of the Implementation Method

[0105] 2-1-1: Overall Structure

[0106] Compared with the display control system 1 of the first embodiment, the display control system 1A of the second embodiment includes a first projector 10A-1 instead of the first projector 10-1, and a second projector 10A-2 instead of the second projector 10-2. In other respects, the overall structure of the display control system 1A of the second embodiment is the same as that of the display control system 1 of the first embodiment, so the figures are omitted.

[0107] Furthermore, in the following description, the same reference numerals will be used for the constituent elements of the display control system 1A of the second embodiment that are the same as those of the display control system 1 of the first embodiment. Also, for the sake of simplicity, the functions of the same constituent elements will be largely omitted. Furthermore, for the sake of simplicity, the following description will mainly focus on the differences between the display control system 1A of the second embodiment and the display control system 1 of the first embodiment.

[0108] 2-1-2: Structure of the first projector 10A-1

[0109] Figure 6 This is a block diagram showing the structure of the first projector 10A-1 according to the second embodiment. The first projector 10A-1 of the second embodiment differs from the first projector 10-1 of the first embodiment in that it has a processing device 120A instead of a processing device 120, and a storage device 130A instead of a storage device 130.

[0110] Storage device 130A replaces the control program PR1 of storage device 130 and stores control program PR1A.

[0111] The processing device 120A replaces the information acquisition unit 122 of the processing device 120 with an information acquisition unit 122A, replaces the output unit 125 with an output unit 125A, and replaces the delay unit 126 with a delay unit 126A. Furthermore, the processing device 120A includes a measurement unit 128 instead of the detection unit 124 of the processing device 120. The processing device 120A reads and executes the control program PR1A from the storage device 130A, and functions as a signal acquisition unit 121, an information acquisition unit 122A, a synchronization unit 123, a measurement unit 128, an output unit 125A, a delay unit 126A, and a display control unit 127.

[0112] Figure 7This is a functional block diagram of the information acquisition unit 122A. The information acquisition unit 122A-2 replaces the second acquisition unit 122-2 already present in the information acquisition unit 122. The function of the second acquisition unit 122A-2 will be described later.

[0113] Return to Figure 6 The measurement unit 128 measures the reference time, which is the time from the internal time to the first time until the first input vertical synchronization signal is initially acquired.

[0114] The output unit 125A outputs the reference time measured by the measurement unit 128 to the second projector 10A-2 via the communication device 140. Similarly, the output unit 125A of the second projector 10A-2 also outputs the reference time measured by the measurement unit 128 to the first projector 10A-1 via the communication device 140. Furthermore, in this specification, the reference time measured by the first projector 10A-1 is referred to as the "first reference time," and the reference time detected by the second projector 10A-2 is referred to as the "second reference time."

[0115] Here, the second acquisition unit 122A-2 acquires the second reference time from the second projector 10A-2 via the communication device 140. Similarly, the second acquisition unit 122A-2 of the second projector 10A-2 also acquires the first reference time from the first projector 10A-1 via the communication device 140.

[0116] In other words, the first projector 10A-1 and the second projector 10A-2 notify each other of their respective measured reference times.

[0117] When the second reference time obtained from the second projector 10A-2 is longer than the first reference time, the delay unit 126A delays the first input vertical synchronization signal obtained by the signal acquisition unit 121 by the difference between the first and second reference times. On the other hand, when the second reference time obtained from the second projector 10A-2 is the same as or shorter than the first reference time, the delay unit 126A does not perform any processing on the first input vertical synchronization signal.

[0118] Similarly, the delay unit 126A of the second projector 10A-2 delays the second input vertical synchronization signal acquired by the signal acquisition unit 121 by the difference between the first and second reference times when the first reference time obtained from the first projector 10A-1 is longer than the second reference time. On the other hand, the delay unit 126A of the second projector 10A-2 does not process the second input vertical synchronization signal when the first reference time obtained from the first projector 10A-1 is the same as or shorter than the second reference time.

[0119] As a result, the first projector 10A-1 can solve the problem of reproducing images with residual deviations when the image signals input to multiple projectors themselves have a deviation of more than one frame between the projectors. In particular, the first projector 10A-1 can solve the problem caused by the deviation in the synchronization of the input image signals, which cannot be solved by simply synchronizing the internal timing between the multiple projectors.

[0120] Furthermore, multiple first moments can be set. Whenever the internal time reaches the first moment, the measurement unit 128 measures the reference time, which is the time from the passing of the first moment to the initial acquisition of the first input vertical synchronization signal. Thereafter, the output unit 125A, the second acquisition unit 122A-2, the delay unit 126A, and the display control unit 127 repeat the above operation.

[0121] As a result, the first projector 10A-1 can, for example, readjust the timing to delay the first input vertical synchronization signal.

[0122] 2-2: Actions of the Implementation Method

[0123] Figure 8 This is a timing diagram illustrating the operation of the display control system 1A according to the second embodiment. Hereinafter, refer to... Figure 8 The operation of the display control system 1A is explained.

[0124] In step S21, the processing device 120A of the first projector 10A-1 functions as the first acquisition unit 122-1. The processing device 120A acquires the standard time from the time server 30.

[0125] In step S22, the processing device 120A of the second projector 10A-2 functions as the first acquisition unit 122-1. The processing device 120A acquires the standard time from the time server 30.

[0126] In step S23, the processing device 120A of the first projector 10A-1 functions as a synchronization unit 123. This processing device 120A synchronizes the internal time referenced in the processing of the first projector 10A-1 with the standard time obtained in step S21.

[0127] In step S24, the processing device 120A of the second projector 10A-2 functions as a synchronization unit 123. This processing device 120A synchronizes the internal time referenced in the processing of the second projector 10A-2 with the standard time obtained in step S22.

[0128] In step S25, the processing device 120A of the first projector 10A-1 functions as a measurement unit 128. The processing device 120A measures the time from the arrival of the internal time to the first time to the initial acquisition of the first input vertical synchronization signal, i.e., the first reference time.

[0129] In step S26, the processing device 120A of the second projector 10A-2 functions as a measurement unit 128. The processing device 120A measures the time from the arrival of the internal time to the first time to the initial acquisition of the second input vertical synchronization signal, i.e., the second reference time.

[0130] In step S27, the processing device 120A of the first projector 10A-1 functions as an output unit 125A. The processing device 120A of the first projector 10A-1 outputs the first reference time measured in step S25 to the second projector 10A-2. Furthermore, the processing device 120A of the second projector 10A-2 functions as a second acquisition unit 122A-2. The processing device 120A of the second projector 10A-2 acquires the first reference time from the first projector 10A-1.

[0131] In step S28, the processing device 120A of the second projector 10A-2 functions as an output unit 125A. The processing device 120A of the second projector 10A-2 outputs the second reference time measured in step S26 to the first projector 10A-1. Furthermore, the processing device 120A of the first projector 10A-1 functions as a second acquisition unit 122A-2. The processing device 120A of the first projector 10A-1 acquires the second reference time from the second projector 10A-2.

[0132] In step S29, the processing device 120A of the first projector 10A-1 functions as a delay unit 126A. This processing device 120A compares the first reference time measured by itself with the second reference time obtained from the second projector 10A-2. If the second reference time is longer than the first reference time, i.e., if the determination result in step S29 is positive, the processing device 120A executes the processing in step S30. Conversely, if the second reference time is the same as or shorter than the first reference time, i.e., if the determination result in step S29 is negative, the processing device 120A executes the processing in step S33.

[0133] In step S30, the processing device 120A of the first projector 10A-1 functions as a delay unit 126A. This processing device 120A delays the first input vertical synchronization signal by the difference between the first reference time and the second reference time.

[0134] In step S31, the processing device 120A of the second projector 10A-2 functions as a delay unit 126A. This processing device 120A compares the second reference time measured by itself with the first reference time obtained from the first projector 10A-1. If the first reference time is longer than the second reference time, i.e., if the determination result in step S31 is positive, the processing device 120A executes the processing in step S32. Conversely, if the first reference time is the same as or shorter than the second reference time, i.e., if the determination result in step S31 is negative, the processing device 120A executes the processing in step S34.

[0135] In step S32, the processing device 120A of the second projector 10A-2 functions as a delay unit 126A. This processing device 120A delays the second input vertical synchronization signal by the difference between the first reference time and the second reference time.

[0136] In step S33, the processing device 120A of the first projector 10A-1 functions as a display control unit 127. The processing device 120A uses the first input vertical synchronization signal to display the first image P1 represented by the first input image signal.

[0137] In step S34, the processing device 120A of the second projector 10A-2 functions as a display control unit 127. This processing device 120A uses the second input vertical synchronization signal to display the second image P2 represented by the second input image signal.

[0138] 2-3: Effects of the implementation method

[0139] The display control method of this embodiment is a display control method for controlling a first projector 10A-1, which is one of the multiple display devices, in a display control system 1A that synchronizes images displayed by multiple display devices. The display control method includes: acquiring a standard time; synchronizing an internal time referenced in the processing of the first projector 10A-1 with the standard time; measuring a first reference time, which is the time from the internal time reaching the first time up to the initial acquisition of a vertical synchronization signal; outputting the first reference time to a second projector 10A-2, which is another display device among the multiple display devices; acquiring a second reference time measured in the second projector 10A-2; if the second reference time of the second projector 10A-2 is longer than the first reference time of the first projector 10A-1, delaying the first input vertical synchronization signal by the difference between the first reference time of the first projector 10A-1 and the second reference time of the second projector 10A-2; and displaying the image represented by the first input image signal using the delayed first input vertical synchronization signal.

[0140] The above-described display control method addresses the problem of image reproduction occurring in a state with residual deviation when the image signals input to multiple projectors exhibit a deviation of more than one frame between the projectors. In particular, the above-described display control method solves the problem caused by the synchronization deviation of the input image signals, which cannot be resolved solely by synchronizing the internal timing of the multiple projectors.

[0141] Furthermore, in the above-described display control method, there are multiple first time settings.

[0142] By setting multiple first moments, the first projector 10A-1 can, for example, readjust the timing to delay the first input vertical synchronization signal.

[0143] The display device in this embodiment is a first projector 10A-1, which is one of the display devices in a display control system 1A that synchronizes images displayed on multiple display devices. The first projector 10A-1 includes a first acquisition unit 122-1, a synchronization unit 123, a measurement unit 128, an output unit 125A, a second acquisition unit 122A-2, a delay unit 126A, and a display control unit 127. The first acquisition unit 122-1 acquires a standard time. The synchronization unit 123 synchronizes the internal time referenced in the processing of the first projector 10A-1 with the standard time. The measurement unit 128 measures the time from the internal time to the first time until the initial acquisition of the vertical synchronization signal, i.e., the first reference time. The output unit 125A outputs the first reference time to the second projector 10A-2, which is another display device among the multiple display devices. The second acquisition unit 122A-2 acquires the second reference time measured in the second projector 10A-2. When the second reference time is longer than the first reference time, the delay unit 126A delays the first input vertical synchronization signal by the difference between the first and second reference times. The display control unit 127 uses the delayed first input vertical synchronization signal to display the image represented by the first input image signal.

[0144] The first projector 10A-1, as the aforementioned display device, solves the problem that when the image signals input to multiple projectors have a deviation of more than one frame between the projectors, the image is reproduced in a state with residual deviation. In particular, the first projector 10A-1 solves the problem caused by the deviation in the synchronization of the input image signals, which cannot be solved by simply synchronizing the internal timing between the multiple projectors.

[0145] 3: Variations

[0146] This disclosure is not limited to the embodiments illustrated above. Specific variations are illustrated below.

[0147] 3-1: Variation Example 1

[0148] In the display control system 1 of the first embodiment, the first image output device 20-1 outputs a first input image signal to the first projector 10-1. Furthermore, the second image output device 20-2 outputs a second input image signal to the second projector 10-2. However, a first USB memory storing first image information representing a first image P1 can also be inserted into the first projector 10-1, and the first projector 10-1 reads the first image information from the first USB memory to display the first image P1. Similarly, a second USB memory storing second image information representing a second image P2 can also be inserted into the second projector 10-2, and the second projector 10-2 reads the second image information from the second USB memory to display the second image P2. In these cases, the first projector 10-1 generates its own vertical synchronization signal used when displaying the first image P1, instead of the first input vertical synchronization signal obtained from the first image output device 20-1. Furthermore, the first projector 10-1 delays the generated vertical synchronization signal according to a reference time. Similarly, the second projector 10-2 generates its own vertical synchronization signal for displaying the second image P2, replacing the second input vertical synchronization signal obtained from the second image output device 20-2. Furthermore, the second projector 10-2 delays its own generated vertical synchronization signal according to a reference time. This also applies to the display control system 1A of the second embodiment.

[0149] 3-2: Variation Example 2

[0150] In the display control system 1 of the first embodiment, the first image output device 20-1 outputs a first input image signal corresponding to the first image P1 to the first projector 10-1. Furthermore, the second image output device 20-2 outputs a second input image signal corresponding to the second image P2 to the second projector 10-2. However, for example, the first image output device 20-1 may output input image signals corresponding to both the first image P1 and the second image P2 to the first projector 10-1, and the first projector 10-1 may output an input image signal corresponding to the second image P2 to the second projector 10-2. Alternatively, the second image output device 20-2 may output input image signals corresponding to both the first image P1 and the second image P2 to the second projector 10-2, and the second projector 10-2 may output an input image signal corresponding to the first image P1 to the first projector 10-1.

[0151] 3-3: Variation Example 3

[0152] In the display control system 1 of the first embodiment, the first image output device 20-1 is directly connected to the first projector 10-1, for example, via an HDMI cable. Similarly, the second image output device 20-2 is directly connected to the second projector 10-2, for example, via an HDMI cable. However, the first image output device 20-1 can also be connected to the first projector 10-1 via a communication network NET in a manner that enables mutual communication. Similarly, the second image output device 20-2 can also be connected to the second projector 10-2 via a communication network NET in a manner that enables mutual communication. This also applies to the display control system 1A of the second embodiment.

Claims

1. A display control method, The display control method includes: Obtain the standard time; To synchronize the internal time referenced in the processing of one of the multiple display devices with the standard time; The reference time is the internal time when the image represented by the input image signal satisfies the conditions. The reference time is output to other display devices among the plurality of display devices; Obtain the reference time detected in the other display device; When the reference time of the other display devices is later than the reference time of the first display device, the vertical synchronization signal is delayed from the reference time of the first display device to the reference time of the other display devices; and The delayed vertical synchronization signal is used to display the image represented by the input image signal. The condition is that the image represented by the input image signal contains a specified image. The image represented by the input image signal is displayed through a display device. The area displayed by the display device includes: an effective area visible to the user; and an ineffective area located outside the effective area and not visible to the user. The specified image is displayed in the invalid area and not in the valid area.

2. The display control method according to claim 1, wherein, The condition is that the image represented by the input image signal is switched from the first input image to the second input image.

3. A display device, The display device is one of the multiple display devices in a system that synchronizes images displayed through multiple display devices, and has the following characteristics: The first acquisition unit, which acquires the standard time; A synchronization unit that synchronizes the internal time referenced during processing in the display device with the standard time; The detection unit detects a reference time, which is the internal time when the image represented by the input image signal meets the conditions. An output unit that outputs the reference time to other display devices among the plurality of display devices; The second acquisition unit acquires the reference time detected by the other display device; The delay unit, when the reference time of the other display device is later than the reference time of the one display device, delays the vertical synchronization signal from the reference time of the one display device to the reference time of the other display device. as well as The display control unit uses the delayed vertical synchronization signal to display the image represented by the input image signal. The condition is that the image represented by the input image signal contains a specified image. The image represented by the input image signal is displayed through a display device. The area displayed by the display device includes: an effective area visible to the user; and an ineffective area located outside the effective area and not visible to the user. The specified image is displayed in the invalid area and not in the valid area.

Images