Information processing system, information processing device, and control method

Abstract

Ensures consistent image quality and responsiveness depending on the displayed content. [Solution] A controller drives pixels arranged in a stationary dynamic region where display contents dynamically change on a stationary basis with one bit on an electrophoretic display panel, and drives pixels arranged in a non-stationary dynamic region with two or more bits, and a host system determines whether or not to define a display region of an element of a display image to be displayed on a display unit as the stationary dynamic region based on information about the dynamic characteristics of the element. This embodiment can be realized in any of the forms of an information processing system, an information processing device, and a control method.

Description

[Technical field]

[0001] The present application relates to an information processing system, an information processing device and a control method, for example, to selecting a driving method for a display device. [Background technology]

[0002] Electrophoretic displays (EPDs) do not consume power while displaying stationary content, and can therefore display a variety of information. EPDs are sometimes used to display information that is primarily text. For example, Patent Document 1 describes applications of EPDs to electronic book terminals, electronic medical records, electronic newspapers, and the like. EPDs are also called electric paper displays, electronic ink displays, and the like.

[0003] However, EPDs have a slower response to display changes than other types of display devices, such as liquid crystal displays and organic light-emitting diode displays. The delay in changes tends to be particularly noticeable when expressing gradations with multiple bits. In a typical EPD, the response time for 1-bit gradation, which displays 2 levels of gradation, is about 100 msec, but for 4-bit gradation, which displays 16 levels of gradation, the response time can reach 500 msec. In general, the greater the gradation bit depth of an EPD, the smoother the gradation that can be displayed, but the slower the responsiveness.

[0004] In addition to the above, when the EPD is displayed in 4-bit gradation, a process called refresh is often required. This is a process in which black or white particles that have been moved to an intermediate position are temporarily gathered at both ends of the electrophoretic electrode in order to display multi-bit gradation. At this time, white or black that is unrelated to the gradation actually required is displayed, so when video content is displayed on a 4-bit gradation EPD, unnecessary white or black is displayed during the slow response, which is annoying. When the EPD is displayed in 1-bit gradation, no refresh process is required. For the above reasons, when using an EPD, 1-bit gradation operation is desired even at the expense of smoothness of gradation for content that changes frequently (video, web browsing, etc.), and 4-bit gradation operation is often desired for content that changes little and requires smoothness of gradation (display of photos, paintings, etc.). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-64421 A Summary of the Invention [Problem to be solved by the invention]

[0006] In this regard, when a pixel difference occurs with the previous frame, it is possible to display the pixel in 1 bit, but depending on the display content, this may give a strange impression. For example, in video content, there may be a mixture of parts where a pixel difference occurs from the previous frame and parts where no pixel difference occurs. In this case, if only the pixels of the part where the difference occurs are displayed in 1 bit, a part where 4 bits are displayed and a part where 1 bit are displayed will be mixed in one video, which creates an uncomfortable feeling. In addition, if the pixel difference of content (e.g., mouse cursor, page switching, etc.) where the position where a significant difference in gradation value occurs between adjacent pixels (hereinafter referred to as "pixel difference") changes from time to time is displayed in 1 bit, the part after the movement is also displayed in 1 bit, resulting in an afterimage on the screen, which may give the user a strange feeling, and therefore there is little point in changing the drive mode. [Means for solving the problem]

[0007] The present application has been made to solve the above-mentioned problems, and an information processing system according to one embodiment of the present application comprises a host system and a display unit, the display unit comprising a controller and an electrophoretic display panel, the controller drives pixels arranged in a steady dynamic region of the electrophoretic display panel, where the display content changes dynamically and constantly, with one bit, and drives pixels arranged in a non-steady dynamic region of the electrophoretic display panel with two or more bits, and the host system determines, for an element of a display image to be displayed on the display unit, whether or not to define the display region of the element as the steady dynamic region, based on information regarding the dynamic characteristics of the element.

[0008] In the above information processing system, the host system may refer to a list indicating predetermined applications, and when the application being executed is the predetermined application, define a display area of ​​the image of the application as a stationary dynamic area.

[0009] In the above information processing system, the host system may determine, when an operation indicating a transition of the display area is detected, the display area as a stationary dynamic area.

[0010] In the above information processing system, the host system may detect an update area that has been updated since the previous frame from the display image of the current frame, and select an update area that occurs with a predetermined frequency or more within a predetermined period up to the current frame and has a common area of ​​a predetermined size or more as a candidate for the steady dynamic area.

[0011] In the above information processing system, the host system may determine the entire display image as a steady dynamic region when an area ratio of a candidate region that is a candidate for the steady dynamic region to the display image exceeds a predetermined area ratio.

[0012] In the above information processing system, when the area ratio of a stationary update region to a candidate region that is a candidate for the steady dynamic region is equal to or less than a predetermined update region area ratio, the host system may detect an edge from the candidate region, and define an image region surrounded by the edge as the steady dynamic region, where the gradation changes with a predetermined frequency or more within a predetermined period up to the current frame, and exclude from the steady dynamic region an image region where the gradation does not change within the predetermined period up to the current frame.

[0013] An information processing device according to a second aspect of the present application is an information processing device that includes a host system and causes a display unit to display a display image on an electrophoretic display panel, the display unit having a controller that drives pixels arranged in a steady dynamic region, where the display content dynamically changes constantly, with one bit and drives pixels arranged in a non-steady dynamic region with two or more bits, and the host system determines, for an element of the display image to be displayed on the display unit, whether or not the display region of the element is to be the steady dynamic region, based on information regarding the dynamic characteristics of the element.

[0014] A control method according to a third aspect of the present application is a control method in an information processing system including a host system and a display unit, the display unit including a controller and an electrophoretic display panel, the controller drives pixels arranged in a steady dynamic area of ​​the electrophoretic display panel, where the display content changes dynamically, with one bit, and drives pixels arranged in a non-steady dynamic area with two or more bits, and the host system determines, for an element of a display image to be displayed on the display unit, whether or not to define the display area of ​​the element as the steady dynamic area based on information regarding the dynamic characteristics of the element. Effect of the Invention

[0015] According to the embodiment of the present application, the subjective quality of the entire displayed image can be improved depending on the display content. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a schematic block diagram illustrating an example of a hardware configuration of the information processing system according to the present embodiment. [Diagram 2] FIG. 2 is a schematic block diagram illustrating an example of a functional configuration of the information processing system according to the present embodiment. [Diagram 3] FIG. 2 is a diagram showing a first example of an image displayed on a display unit. [Figure 4] FIG. 11 is a diagram showing a second example of an image displayed on the display unit. [Diagram 5] FIG. 13 is an explanatory diagram showing an example of setting a steady dynamic region and a non-steady dynamic region. [Figure 6] 1 is an explanatory diagram illustrating an overview of a method for determining a steady dynamic region according to an embodiment of the present invention; [Figure 7] 4A to 4C are diagrams illustrating a first example of a method for determining a steady dynamic region according to the present embodiment. [Figure 8] 11 is a diagram showing a second example of a method for determining a steady dynamic region according to the present embodiment. FIG. [Figure 9] 13A to 13C are diagrams illustrating a third example of a method for determining a steady dynamic region according to the present embodiment. [Figure 10] FIG. 11 is an explanatory diagram illustrating an example of a size filter. [Figure 11] FIG. 13 is an explanatory diagram illustrating a stability filter. [Figure 12] 13 is a diagram showing a fourth example of a method for determining a steady dynamic region according to the present embodiment. FIG. [Figure 13] 11A to 11C are diagrams illustrating a method for setting a steady dynamic region according to the present embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present application will be described with reference to the drawings. First, a configuration example of an information processing system S1 according to an embodiment of the present application will be described. Fig. 1 is a schematic block diagram showing a hardware configuration example of the information processing system S1 according to the present embodiment.

[0018] The information processing system S1 includes a host system 10, a display unit 30, and an input device 40. The information processing system S1 may be realized as a single electronic device having the host system 10, the display unit 30, and the input device 40. The information processing system S1 may also be configured such that the host system 10, and one or both of the display unit 30 and the input device 40 are configured separately. The information processing system S1 may be realized as any type of information processing device, such as a personal computer, a tablet terminal, a mobile phone, or an e-book reader. The host system 10 acquires display data showing a display image according to various programs, and outputs the acquired display data to the display unit 30. The host system 10 may monitor an operation signal input from the input device 40 and operate with reference to the input operation signal. In this application, operating based on an operation signal input from the input device 40 may be referred to as "operating according to an operation" or the like.

[0019] The display unit 30 is an EPD (Electric Paper Display) device that displays a display image based on display data input from the host system 10. The EPD device is an electrophoretic display device having pixels that employ an electrophoretic system. A display image, or simply an image, refers to the display content that appears on the screen, i.e., spatial changes in brightness and color. A display image includes elements such as patterns, figures, symbols, characters, or combinations of any or all of these. The display unit 30 has a screen on which pixels are arranged at regular intervals, and displays a display image based on the display data input from the host system 10 on a display medium. The display unit 30 is capable of displaying a display image according to any of a plurality of predetermined drive modes.

[0020] Depending on the driving mode, the bit depth of the gradation value representing the gradation of each pixel differs. The gradation corresponds to the brightness of the pixel, that is, the density or shade. The gradation value is also called a pixel value or a signal value. In particular, the gradation value related to color display is also called a color signal value. The bit depth corresponds to the number of bits that express the gradation value. The larger the bit depth, the wider the range of the gradation value, but the range of the gradation expressed is common. In other words, regardless of the bit depth, the gradation corresponding to the maximum value and the minimum value of the gradation value are respectively common. The larger the bit depth, the smaller the difference in gradation between adjacent gradation values ​​(also called the gradation width). When the bit depth is 1 bit, only two gradations are expressed: the first gradation corresponding to the maximum value (e.g., 1) (e.g., black in the case of monochrome) and the first gradation corresponding to the minimum value (e.g., 0) (e.g., white). However, while the larger the bit depth, the more gradations can be expressed, the lower the responsiveness of the pixel. Driving pixels with a bit depth greater than 2 bits requires a refresh process every predetermined refresh period.

[0021] The input device 40 is capable of accepting a user's operation and generates an operation signal in response to the accepted operation. The input device 40 outputs the generated operation signal to the host system 10. As the input device 40, for example, a general-purpose device such as a touch sensor, a mouse, a keyboard, or a joystick may be used, or a dedicated device such as a button, a knob, or a dial may be used. The touch sensor applied as the input device 40 may be integrated with the EPD panel 34 of the display unit 30 and configured as a touch panel.

[0022] As described later, the host system 10 according to the present embodiment specifies, as a stationary dynamic region, a region in which an image constituting the display contents changes steadily over time among the display images displayed on the display unit 30. In general, an image is expressed by a distribution of grayscale values ​​for pixels arranged adjacently at different positions, that is, a grayscale distribution. The change in the image is expressed by a change in the grayscale distribution between frames. The host system 10 notifies the display unit 30 of the display image and the specified stationary dynamic region. For the stationary dynamic region notified by the host system 10, the display unit 30 displays the display image using a driving mode that is more responsive than the non-stationary dynamic region, which is the other region. For the stationary dynamic region, a decrease in image quality is acceptable, but responsiveness is required. For the non-stationary dynamic region, a decrease in responsiveness is acceptable, but high image quality is required. Therefore, the quality and responsiveness can be achieved simultaneously for the entire display image, thereby improving subjective quality.

[0023] Next, an example of the hardware configuration of the information processing system S1 will be described. The host system 10 includes a processor 12, a main memory 14, a chipset 20, and an auxiliary storage medium 22. The host system 10 controls the overall functions of the information processing system S1.

[0024] The processor 12 controls the overall function of the device including the host system 10. For example, one or more CPUs (Central Processing Units) are applied as the processor 12. The processor 12 executes a predetermined program and cooperates with the main memory 14, the chipset 20, the auxiliary storage medium 22, and some or all of the other hardware to perform the functions of the host system 10. In this application, the processor 12 or other hardware executing processing instructed by instructions written in a program may be referred to as "executing a program" or "running a program."

[0025] The main memory 14 is a writable memory used as a working area for the processor 12, i.e., an area for reading programs to be executed and various setting data, and an area for writing processing data acquired by executing the programs. The main memory 14 is configured to include, for example, a plurality of DRAM (Dynamic Random Access Memory) chips. The programs to be executed include an OS (Operating System), various device drivers for controlling peripheral devices, various services / utilities, application programs (sometimes referred to as "apps" in this application), and the like. The processor 12 and main memory 14 function as a minimum system device that constitutes the host system 10. The host system 10 includes a system device as hardware, and software such as an OS and a schedule task.

[0026] The chipset 20 includes one or more controllers and can be connected to other devices, including the display unit 30, to input and output various data. The chipset 20 is also called a PCH (Platform Controller Hub). The chipset 20 includes one or a combination of bus controllers such as a Universal Serial Bus (USB), an Advanced Technology Attachment (Serial ATA), a Serial Peripheral Interface (SPI) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express bus, and a Low Pin Count (LPC).

[0027] The auxiliary storage medium 22 stores various programs and data. The various programs include, for example, firmware, device drivers, services / utilities, and applications. These programs are executed by the processor 12. The stored data includes data to be processed by the processor 12, and data generated or input by the processing. The auxiliary storage medium 22 includes a nonvolatile memory such as a flash memory. As the auxiliary storage medium 22, a solid state drive (SSD), a hard disk drive (HDD), or the like may be used.

[0028] The display unit 30 includes a timing controller 32 and an EPD panel 34 . Display data is input from the host system 10 to the timing controller (T-CON: Timing Controller) 32 according to an input / output method defined by a predetermined input / output standard. As the input / output method, a method defined by any one of the DP (Display) standard, MIPI (Mobile Industry Processor Interface) standard, HDMI (registered trademark) (High-Definition Multimedia Interface) standard, etc. may be used. The timing controller 32 quantizes the gradation value of each pixel indicated by the input display data with a bit depth corresponding to the drive mode, and converts it into a quantized value. The timing controller 32 generates a drive signal indicating the gradation of each pixel in accordance with the display timing of the EPD panel 34 in order to display each pixel with a gradation corresponding to the converted quantized value. The timing controller 32 outputs the generated drive signal to the EPD panel 34. The timing controller 32 performs a refresh process at a predetermined refresh rate depending on the drive mode, and sets the gradation value to a predetermined reference value (for example, a minimum value). The timing controller 32 may be equipped with an arithmetic circuit, for example, an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array), and may execute a rewritable program to realize its functions, or may be realized by dedicated hardware.

[0029] The EPD (Electric Phoretic Display) panel 34 has a substrate, a plurality of pixels, and a drive circuit. The drive circuit applies a voltage corresponding to a specified gradation to a pixel corresponding to the timing specified by a drive signal input from a timing controller 32. The drive circuit includes, for example, a TTL (Transistor-Transistor Logic) circuit. A plurality of pixels are periodically arranged two-dimensionally on the surface of the substrate. Each pixel expresses a gradation according to the voltage applied from the drive circuit. Each pixel has a pair of electrodes, which are held by sandwiching a solution. Charged particles made of pigment float in the solution. The charged particles move toward an electrode of opposite polarity to themselves according to the applied voltage. This movement brings about a change in gradation.

[0030] Next, an example of the functional configuration of the information processing system S1 will be described below. Fig. 2 is a schematic block diagram showing an example of the functional configuration of the information processing system S1 according to this embodiment. The host system 10 includes an OS processing unit 102, an application execution unit 104, a mode setting unit 106, and a graphics processing unit .

[0031] The OS processing unit 102 executes an OS (Operating System) and provides its functions. In this application, execution of an OS or other program means executing processing instructed by various commands written in the program. Functions of the OS include management of resources used for arithmetic processing, data storage, etc., and provision of a standard interface for application programs (sometimes referred to as "applications" or "apps" in this application) and users. The OS processing unit 102 executes, for example, launching applications, monitoring the execution state of applications after launching, setting a display area for application images, priority control for components of a display image, cursor display, etc.

[0032] The OS processing unit 102 starts an application instructed by an operation signal in response to an operation, and starts its execution. The OS processing unit 102 may start the execution of an application whose usage environment satisfies a predetermined start condition. For example, the start condition may be that the current time reaches a predetermined start time (start timer). The above application image refers to a display image acquired by processing an application being executed. The application image is configured by being accommodated in a rectangular window (sometimes called an "application window" in this application). The OS processing unit 102 executes, in response to an operation, designation of an application window to be focused on as a display target, change of the size or position on the display image of the application window, erasure, redisplay, and the like. The OS processing unit 102 gives priority to an application image that has been started to be displayed later or an application image that has been operated later among a plurality of application images. When giving priority to displaying a certain application image, the OS processing unit 102 displays the contents of the shared area of ​​a certain application image in a shared area shared with other application images among a certain application image, and discards the contents of the shared area of ​​the other application images without displaying them.

[0033] The OS processing unit 102 executes various screen displays as processing instructed by the OS. Various screen parts (i.e., UI (User Interface) components) are used in the screen display. For example, the OS processing unit 102 displays a cursor at a position on a display image instructed according to an operation. When a position within an application image area is instructed according to an operation, the OS processing unit 102 executes a function of the application corresponding to the position (for example, turning on / off a specific function by pressing a button, etc.). When a position outside the application image area is instructed according to an operation, the OS processing unit 102 executes an OS-specific function corresponding to the position (for example, moving a data file by a drag operation, etc.). The OS processing unit 102 composes a display image to be displayed on the display unit 30 by superimposing an element image provided by a function specific to the OS and an application image being executed at that time with a predetermined priority.

[0034] The application execution unit 104 executes an application whose start has been instructed by the OS processing unit 102. In processing the application, the application execution unit 104 composes a display image to be displayed as a function of the application. For example, in a video playback application, a display image constituting the video whose playback has been instructed is constructed. The constructed display image is accommodated in an application window assigned to the application.

[0035] The mode setting unit 106 identifies a stationary dynamic region from the display image to be displayed on the display unit 30, and distinguishes it from the non-stationary dynamic region, which is the other region. The mode setting unit 106 monitors the grayscale distribution in the display image for each frame having a different time, or the occurrence of information that may be a factor of the grayscale distribution. For example, the mode setting unit 106 determines, as a stationary dynamic region, a region in which parts in which the grayscale distribution changes occur with a certain frequency or more during a predetermined period up to that point in time are spatially connected. For example, in a stationary dynamic region, if the grayscale distribution does not change during a predetermined period up to that point in time, the mode setting unit 106 changes the region to a non-stationary dynamic region. As will be described later, the mode setting unit 106 generates a drive command including setting information indicating a part of the display image that is occupied by the stationary dynamic region. The mode setting unit 106 outputs the generated drive command to the display unit 30. As a result, an image is displayed for the stationary dynamic region using a drive mode different from that for the non-stationary dynamic region. An example of a method for determining a stationary dynamic region will be described later.

[0036] The graphics processing unit 108 recognizes the display unit 30 connected to the host system 10. The graphics processing unit 108 generates display data showing the display image configured by the OS processing unit 102 for each frame. The display image for one frame is expressed by a gradation value for each pixel. The bit depth of the gradation value is, for example, 8 to 10 bits. The graphics processing unit 108 outputs the generated display image to the display unit 30, and causes the display image to be displayed. The function of the graphics processing unit 108 may be realized by executing a graphics driver included with the OS, or may be realized by executing a device driver dedicated to the display unit 30.

[0037] Next, an example of the functional configuration of the timing controller 32 will be described. The timing controller 32 includes a quantization unit 322 , a dithering unit 324 , and a drive signal generation unit 326 . The quantization unit 322 has a frame buffer (not shown). The frame buffer temporarily stores display data input from the host system 10, and whenever new display data is input, the stored display data is updated to the new display data. The quantization unit 322 extracts setting information from the drive command input from the host system 10, identifies a stationary dynamic region indicated in the extracted setting information, and identifies a region other than the stationary dynamic region as a non-stationary dynamic region. The quantization unit 322 sets a drive mode for the stationary dynamic region that has higher responsiveness than a drive mode for the non-stationary dynamic region. The quantization unit 322 sets a bit depth (e.g., 1 bit) for the stationary dynamic region that is smaller than the bit depth (e.g., 4 bits) for the non-stationary dynamic region.

[0038] The smaller the set bit depth is, the shorter the period in which the quantization unit 322 reads out from the frame buffer the grayscale values ​​of the pixels located in the stationary dynamic area and the non-stationary dynamic area. The quantization unit 322 quantizes the grayscale value of each pixel at a bit depth specified by the drive mode set for the region to which the pixel belongs, and converts it into a quantized value. The quantization unit 322 notifies the dithering unit 324 of the quantization value for each pixel belonging to a region with a bit depth of 1 bit, together with the setting information and the display data.

[0039] For an area where the bit depth is 2 bits or more, the quantization unit 322 notifies the driving signal generation unit 326 of the quantization value for each pixel belonging to that area. This is because dithering is not performed for that area. However, the quantization unit 322 performs a refresh process for the pixels in that area at a predetermined refresh cycle. The refresh cycle may be set to be longer for a driving mode with a larger bit depth. In the refresh process, the quantization unit 322 sets the quantization value for each pixel to a predetermined reference value (for example, a quantization value corresponding to the maximum gradation or the minimum gradation), and then returns it to the original quantization value. Every time the quantization value is changed, the quantization unit 322 notifies the driving signal generation unit 326 of the changed quantization value.

[0040] The dithering unit 324 performs dithering in the dynamic region specified by the mode setting unit 106, and spatially disperses the quantization error generated by quantizing the display data. The dithering unit 324 specifies the stationary dynamic region based on the setting information notified by the quantization unit 322. For example, the dithering unit 324 calculates the difference between the gradation value before quantization and the quantized value for each pixel in the dynamic region as the quantization error, and disperses the calculated quantization error to the surrounding pixels. Note that dithering does not necessarily have to be performed. For example, dithering is less necessary for content such as text that has only black and white gradations.

[0041] As a method for distributing the quantization error, any method such as a matrix operation using a Floyd-Steinberg matrix, a matrix operation using an Atkinson matrix, or a minimum average error method may be adopted. According to the matrix operation, the quantization error of the target pixel to be calculated is allocated to the unprocessed pixel to which the unprocessed pixel is distributed at a predetermined ratio for each method and added to the gradation value. Since the target pixel is changed to an unprocessed adjacent pixel every time a matrix operation is performed, the gradation value before quantization in the unprocessed pixel and the quantization value obtained by quantizing the gradation value are not finally determined until the target pixel itself becomes the target pixel. The dithering unit 324 adopts the quantization value finally obtained by the process of S01 for each pixel in the stationary dynamic region and updates the original quantization value to the newly adopted quantization value. The dithering unit 324 notifies the driving signal generating unit 326 of the quantization value of each pixel including the updated quantization value.

[0042] The drive signal generation unit 326 generates a drive signal having a voltage corresponding to the quantized value of each pixel notified by the quantization unit 322 or the dithering unit 324. The drive signal generation unit 326 outputs a drive signal having a voltage set for each pixel at a different timing for each pixel in a frame period to the EPD panel 34. The voltage set for each pixel is applied to the EPD panel 34, and the pixel is displayed with a grayscale corresponding to the applied voltage. It should be noted that the dithering unit 324 may be omitted in the timing controller 32. In that case, the quantized value for each pixel obtained in the quantization unit 322 is notified to the drive signal generation unit 326 and used to generate the drive signal.

[0043] Next, an example of an image displayed on the display unit 30 will be described. 3 and 4 show examples of images displayed in the 1-bit and 4-bit driving modes, respectively. The 1-bit and 4-bit driving modes are driving modes that quantize gradation values ​​by 1 bit and 4 bits, respectively. Figure 4 shows more subtle changes in gradation than Figure 3. In the 1-bit mode, only maximum and minimum gradations are expressed, so dithering is used to express the spatial distribution of gradation as the ratio of pixels with the maximum value to pixels with the minimum value. However, the spatial distribution of gradation can only be expressed in an area significantly larger than the pixel interval, so the image quality is degraded compared to the 4-bit mode. On the other hand, the 1-bit mode has higher responsiveness than the 4-bit mode, so it can handle more frequent updates and does not require refresh processing.

[0044] Therefore, the quantization unit 322 according to the present embodiment sets a driving mode for the stationary dynamic region that is more responsive than the driving mode for the non-stationary dynamic region. The host system 10 defines a region in which changes in gradation distribution occur at a frequency equal to or greater than a predetermined frequency within a predetermined period up to that point and are spatially connected as a stationary dynamic region, and defines the other regions as non-stationary dynamic regions. Therefore, a method that is more responsive than the non-stationary dynamic region is set for the stationary dynamic region where changes in gradation or image movement occur frequently. For example, in the example of FIG. 5, the region including the part where the image of a moving vehicle appears at that point and the part where the image of the vehicle passed just before that is set as the stationary dynamic region da, and the surrounding region is set as the non-stationary dynamic region na. In the stationary dynamic region, the image changes over time, and a degradation in image quality due to a coarse gradation range is acceptable. In the non-stationary dynamic region, the image quality degradation is suppressed by a fine gradation range, and a time change in the image is not required. Therefore, the subjective quality of the image displayed on the display unit 30 is improved compared to when the entire displayed image is displayed in one driving mode.

[0045] Next, a specific example of a method for determining a stationary dynamic region will be described. In the following description, a case where a 1-bit mode is set in the stationary dynamic region and a 4-bit mode is set in the non-stationary dynamic region will be illustrated. The stationary dynamic region will be referred to as a "1-bit region" and the non-stationary dynamic region will be referred to as a "4-bit region." FIG. 6 is an explanatory diagram illustrating an outline of a method for determining a stationary dynamic region according to this embodiment.

[0046] (Step S102) The mode setting unit 106 of the host system 10 monitors whether or not there is an application instructed to be started by the OS processing unit 102. The mode setting unit 106 determines whether or not the application instructed to be started is an application related to 1-bit display based on whether or not the name of the application instructed to be newly started is included in a 1-bit application list previously set in the mode setting unit 106 (app name checker). The 1-bit application list is previously set with the names of applications that instruct image display in 1-bit mode (hereinafter, sometimes referred to as "1-bit applications"). Examples of 1-bit applications include applications for playing video, and applications for editing or creating images.

[0047] (Step S104) The mode setting unit 106 monitors the behavior of the OS notified by the OS processing unit 102 (OS operation checker). The behavior of the OS refers to the display of an image and its changes caused by the execution of the OS. For example, this includes the display of a window that contains an element image that is an element of the displayed image, its movement or deformation, the display and movement of a cursor related to an operation, etc. (Step S106) The mode setting unit 106 monitors the major change status of the element image that is an element of the display image (major motion operation checker). The element image may be, for example, a moving image or an animation image included in an application image instructed by an application. The major change status includes the frequency of the change within a predetermined period up to that point in time and the stability of the area where the change occurs.

[0048] (Step S108) The mode setting unit 106 determines a 1-bit area based on the detection result in any one step or any combination of steps S102 to S106. (Step S110) The mode setting unit 106 notifies the timing controller 32 of the display unit 30 of setting information indicating the determined 1-bit area.

[0049] Next, a specific example of a method for determining a stationary dynamic region according to the present embodiment will be described. Fig. 7 is a diagram showing a first example of a method for determining a stationary dynamic region according to the present embodiment. The method illustrated in Fig. 7 corresponds to a specific example of a method for determining a stationary dynamic region based on application name confirmation. (Step S202) The mode setting unit 106 acquires an application name list from the OS processing unit 102. The application name list includes the name of each application that is being executed in the OS processing unit 102 and that is accompanied by image display, and information on the display area thereof. (Step S204) The mode setting unit 106 excludes the display areas of applications whose display areas have a predetermined size (for example, 200×200 pixels to 400×400 pixels) from candidates for stationary dynamic areas.

[0050] (Step S206) Mode setting unit 106 refers to a 1-bit application list previously set in the mode setting unit 106, and determines, for each application notified in the application name list, whether it corresponds to a 1-bit application, and excludes the display area of ​​applications that do not correspond from the candidates for stationary dynamic area. (Step S208) The mode setting unit 106 determines whether the number of applications with image display that are being executed and that remain without being excluded is 1. If it is determined that there is 1 (step S208 YES), the process proceeds to step S216. If it is determined that there are 2 or more (step S208 NO), the process proceeds to step S210.

[0051] (Step S210) The mode setting unit 106 judges whether the timing controller 32 of the display unit 30 connected to the mode setting unit 106 can set multiple 1-bit regions in the display area. For example, when detecting the display unit 30 or the timing controller 32, the mode setting unit 106 can judge whether the model notified by the device information input from the display unit 30 or the timing controller 32 includes a model previously described in the set model list, and thereby judges whether the model can set multiple 1-bit regions. The ability to set multiple 1-bit regions corresponds to the ability to realize quantization of gradation values ​​with different bit depths independently for each of multiple partial areas included in the display area. If it is judged that the setting is possible (step S210 YES), the process proceeds to step S214. If it is judged that the setting is possible (step S210 NO), the process proceeds to step S212.

[0052] (Step S212) The mode setting unit 106 sets the entire display area as a 1-bit area. (Step S214) The mode setting unit 106 sets the display area for each application being executed as a 1-bit area, and sets the other areas as a 4-bit area. (Step S216) The mode setting unit 106 sets the display area of ​​the one application as a 1-bit area, and sets the other areas as a 4-bit area, and then ends the process of FIG.

[0053] Fig. 8 is a diagram showing a second example of a method for determining a steady dynamic region according to the present embodiment. The technique illustrated in Fig. 8 corresponds to a specific example of a determination method based on confirmation of the OS behavior. (Step S302) The mode setting unit 106 monitors a user operation that instructs a transition of the display area among the processes in the OS processing unit 102. The transition of the display area includes, for example, any one of the items such as movement, size or shape change of a screen component displayed by the OS, or a combination of any two or more items. The screen components to be monitored include a window, a cursor, an icon, and the like.

[0054] (Step S304) The mode setting unit 106 excludes screen elements whose display area size is equal to or smaller than a predetermined size (e.g., 200×200 pixels to 400×400 pixels) from the evaluation target (size filter). By excluding relatively small screen elements from the evaluation target, screen elements that have a large impact on the user's visibility remain. (Step S306) When a screen component instructed by a user operation to change the display area is detected, the mode setting unit 106 determines the entire display area as a 1-bit area, and then ends the process of FIG.

[0055] FIG. 9 is a diagram showing a third example of a method for determining a stationary dynamic region according to the present embodiment. The method illustrated in FIG. 9 corresponds to a specific example of a determination method based on a major transition confirmation. This method aims to detect a region where a change in gradation distribution occurs steadily (i.e., continuously for a predetermined time or more) at the same place. Therefore, the problem may not be solved by simply setting a region where a difference occurs between the previous frame and the current frame as a stationary dynamic region. For example, depending on the movement of the cursor moved by a user operation or the change in the moving image, a sense of incongruity may arise due to the difference in the display mode with the surroundings. In addition, when the page is switched, the display contents are significantly changed before and after the switch, so the effect of switching the drive mode is not achieved. For example, even if the drive mode is maintained in the 4-bit mode, the entire display area is rewritten by refreshing. In contrast, even if the drive mode is changed from the 4-bit mode to the 1-bit mode to rewrite the display image and then returned to the 4-bit mode, there is no difference in that the display image is rewritten.

[0056] In this example, the mode setting unit 106 obtains an update area indicating a gradation or image movement from the previous frame to the current frame. The mode setting unit 106 uses, for example, a DR (Dirty Rectangle) area generated by a function of Windows (registered trademark) as the update area. The DR area is a rectangular area including pixels where pixel changes have occurred, so it does not necessarily match the area where the moving image is actually displayed. In addition, depending on the specifications of the OS, a DR area may be generated even if the screen is not actually changing. For example, a transparent window (hereinafter referred to as a "transparent window") that is not actually displayed may be temporarily generated to organize the order of display objects, and the area of ​​the transparent window may be reported as the DR area. Therefore, the mode setting unit 106 evaluates the stability of the DR area and adopts a DR area that is determined to be stable. In addition, the display area of ​​the moving image cannot be specified by a mere change in the gradation value of each pixel from the previous frame to the current frame. Therefore, the mode setting unit 106 detects edges that appear constantly in the display image. The mode setting unit 106 detects a change in the gradation distribution within the image area surrounded by the detected edges.

[0057] (Step S402) The mode setting unit 106 monitors the DR area detected by the OS processing unit 102. (Step S404) The mode setting unit 106 determines whether the cursor displayed at that time is moving. If the cursor is moving, the process in FIG. 9 is terminated without executing the processes in and after step S406. This is because the movement of the cursor indicates the occurrence of a user operation, and therefore the user's attention is relatively focused on the operation, so that it is considered that there is little impact on visibility. (Step S406) The mode setting unit 106 performs size evaluation for each DR region (size filter). In the size evaluation, DR regions whose size is equal to or smaller than a predetermined size (e.g., 200×200 pixels to 400×400 pixels) in frames within a predetermined period up to that point (e.g., the most recent 5 to 15 frames) are excluded from the target of the next stability evaluation. In the example of FIG. 10, the lower right DR region appearing in the second and third frames of the period is excluded.

[0058] (Step S408) The mode setting unit 106 performs stability evaluation for each DR region (stability filter). In the stability evaluation, it is evaluated whether or not the DR regions occupy a common region that is equal to or larger than a predetermined frequency and equal to or larger than a predetermined size within a predetermined evaluation period up to that point. However, a region in which the size of the common region is equal to or smaller than a predetermined size (for example, 200×200 pixels to 400×400 pixels) is excluded from the evaluation target. In the example of FIG. 11, it is determined whether or not there is a region that is equal to or larger than a predetermined size in three or more frames within a period of five frames up to that point. In FIG. 11, 1-2, etc. indicate the second DR region of the first frame. The number of DR regions that occurred during this period is 3, 1, 2, 2, and 2 in the first, second, third, fourth, and fifth frames, respectively. Among them, the region that is shared over three or more frames is filled. Among them, the size of the region filled with a shaded area is equal to or smaller than a predetermined size, so it is excluded from the evaluation target. The mode setting unit 106 can determine the second DR region of the fourth frame and the first DR region of the fifth frame as stable DR regions having an area that is equal to or larger than a predetermined size for three or more frames during the evaluation period. The mode setting unit 106 adopts the DR region evaluated as stable as a target for subsequent processing, and excludes the DR region not evaluated as stable from the target for subsequent processing.

[0059] (Step S410) The mode setting unit 106 judges whether or not a DR area having a predetermined ratio (for example, 70 to 90%) or more exists within the display area of ​​one application. If it is judged that the DR area exists (step S410 YES), the process proceeds to step S412. If it is judged that the DR area does not exist (step S410 NO), the process proceeds to step S414. (Step S412) The mode setting unit 106 judges whether or not a DR region having a predetermined ratio or more exists at the same position without moving. If it is judged that it exists (step S412 YES), the process proceeds to step S418. If it is judged that it does not exist (step S412 NO), the process proceeds to step S416.

[0060] (Step S414) The mode setting unit 106 determines the entire display area as a 1-bit area. (Step S416) Mode setting unit 106 determines the display area of ​​the application currently being executed as a 1-bit area. (Step S418) The mode setting unit 106 analyzes the image displayed in the DR area determined to exist at the same position and determines a 1-bit area. It is presumed that the DR area determined to exist at the same position contains a moving image.

[0061] Next, a method for determining a 1-bit region by analyzing an image will be described. Fig. 12 is a diagram showing a fourth example of a method for determining a stationary dynamic region according to this embodiment. Fig. 12 shows an example of a method for determining a 1-bit region as a stationary dynamic region in step S418 of Fig. 9. (Step S502) The mode setting unit 106 detects an image within the DR region existing at the same position from the displayed image as an analysis target. (Step S504) The mode setting unit 106 executes a known edge detection process on the image to be analyzed to detect edges.

[0062] (Step S506) The mode setting unit 106 identifies a spatially continuous image area surrounded by the detected edges. If an image area surrounded by edges cannot be identified, the mode setting unit 106 may identify a rectangular image area surrounded by four horizontal or vertical line segments that are similar to the detected edges. The mode setting unit 106 identifies an area of ​​the identified image area that is equal to or larger than a predetermined size as a candidate for a 1-bit area. The mode setting unit 106 determines whether or not a pixel change occurs in the identified image region. A pixel change means that there is a pixel that has a change in gradation. If there are multiple image regions in which pixel changes have occurred, the mode setting unit 106 may select the largest of these regions. The mode setting unit 106 defines the image region in which pixel changes have occurred as a 1-bit region.

[0063] Next, a method of updating the setting of the stationary dynamic region will be described. Fig. 13 is a diagram illustrating a method of setting the stationary dynamic region according to this embodiment. In the example of Fig. 13, it is assumed that the 1-bit mode is set as valid for the stationary dynamic region, the 4-bit mode is set as invalid, and the 4-bit mode is set as valid for the non-stationary dynamic region, and the 1-bit mode is set as invalid. (Step S602) The mode setting unit 106 identifies an image area that is not moving and is at least a predetermined size within the display image. Here, the mode setting unit 106 may adopt the image area determined by the process of step S506 in FIG. (Step S604) The mode setting unit 106 excludes from the processing target an image area in which a pixel change due to cursor movement is detected. Since the pixel change due to cursor movement is temporary and predicted by the user operation, a degradation in image quality at that time is acceptable.

[0064] (Step S606) The mode setting unit 106 judges whether or not the 1-bit mode is valid for the specified image area, that is, whether or not it is set as a 1-bit area. If it is judged to be valid (step S606 YES), the process proceeds to step S610. If it is judged to be invalid (step S606 NO), the process proceeds to step S608. (Step S608) The mode setting unit 106 determines whether or not pixel changes have occurred in the image region at a certain frequency (e.g., 60 to 80%) or more in a predetermined period (e.g., 5 to 15 frames) immediately preceding that point in time. If it is determined that pixel changes have occurred (step S608 YES), the process proceeds to step S612. If it is determined that pixel changes have not occurred (step S608 NO), the process proceeds to step S614. (Step S610) The mode setting unit 106 determines whether or not a pixel change has occurred at least once in the image area within a predetermined period (e.g., 5 to 15 frames) up to that point in time. If it is determined that a pixel change has occurred (step S610 YES), the process proceeds to step S614. If it is determined that a pixel change has not occurred (step S610 NO), the process proceeds to step S616.

[0065] (Step S612) The mode setting unit 106 enables the 1-bit mode for the specified image area and disables the 4-bit mode. (Step S614) Mode setting unit 106 does not change the drive mode for the identified image region. (Step S616) The mode setting unit 106 cancels the 1-bit mode for the identified image region and changes it to the 4-bit mode.

[0066] As described above, the information processing system S1 according to this embodiment includes the host system 10 and the display unit 30, and the display unit 30 includes a controller (e.g., the timing controller 32) and an electrophoretic display panel (e.g., the EPD panel 34). The controller drives pixels arranged in a stationary dynamic region, where the display content changes dynamically, with one bit for the electrophoretic display panel, and drives pixels arranged in a non-stationary dynamic region with two or more bits. The host system 10 determines whether or not to define a display region of an element of a display image to be displayed on the display unit 30 as a stationary dynamic region based on information about the dynamic characteristics of the element. According to this configuration, whether or not a display area is a stationary dynamic area in which display contents change dynamically in a stationary manner is determined for an element of a display image according to its dynamic characteristics. In the stationary dynamic area, pixels are driven by 1 bit, and in the non-stationary dynamic area, pixels are driven by 2 bits. Therefore, in the stationary dynamic area, image changes are expressed with higher tracking ability, and deterioration of image quality due to quantization is allowed. In contrast, in the non-stationary dynamic area, display with subtle gradations is possible, and tracking ability to gradation changes is not required. Therefore, according to the dynamic characteristics of the elements constituting the display image, a stationary dynamic area corresponding to tracking ability to changes and a non-stationary dynamic area that emphasizes image quality are used selectively. Therefore, the subjective quality perceived as the entire display image can be improved without the user performing complicated operations. In addition, since a refresh process is not necessarily required in the stationary dynamic area in which pixels are driven by 1 bit, by limiting the target of the refresh process to the non-stationary dynamic area, power consumption can be reduced more than when a refresh process is performed uniformly on the entire display area.

[0067] This embodiment may also be implemented as follows. The host system 10 may refer to a list indicating predetermined applications (for example, a 1-bit app list), and when the application being executed is the predetermined application, may determine the display area of ​​the image of the application as a stationary dynamic area. Host system 10 may define a display area (eg, a window area) as a constant dynamic area when an operation indicating a transition of the display area is detected.

[0068] The host system 10 may detect update regions (e.g., DR regions) that have been updated since the previous frame from the displayed image of the current frame, and select update regions that occur with a predetermined frequency or more within a predetermined period up to the current frame and have a common area of ​​a predetermined size or more as candidates for steady dynamic regions (e.g., a stability filter). The host system 10 may exclude update regions that are less than a certain size from candidates for constant dynamic regions (eg, a size filter). The host system 10 may determine the entire display image as a constant dynamic region when the area ratio of a candidate region that is a candidate for a constant dynamic region to the display image exceeds a predetermined area ratio.

[0069] When the area ratio of a stationary update region to a candidate region that is a candidate for a steady dynamic region is equal to or less than a predetermined update region area ratio, the host system 10 may detect edges from the candidate region, and define as a steady dynamic region an image region surrounded by the detected edges in which the gradation changes with a predetermined frequency or more within a predetermined period up to the current frame, and exclude from the steady dynamic region an image region in which the gradation does not change within the predetermined period up to the current frame.

[0070] This embodiment may be an information processing device that includes a host system 10 and causes a display unit 30 to display a display image, the display unit 30 including a controller (e.g., a timing controller 32) that drives pixels arranged in a stationary dynamic region with 1 bit and drives pixels arranged in a non-stationary dynamic region with 2 bits or more for an electrophoretic display panel (e.g., an EPD panel 34). The host system 10 determines, for an element of a display image to be displayed on the display unit 30, whether or not the display region of the element is to be a stationary dynamic region, based on information on the dynamic characteristics of the element.

[0071] This embodiment is a control method in an information processing system S1 having a host system 10 and a display unit 30, in which the display unit 30 has a controller (e.g., a timing controller 32) and an electrophoretic display panel (e.g., an EPD panel 34), in which the controller drives pixels arranged in a steady dynamic area of ​​the electrophoretic display panel with one bit and drives pixels arranged in a non-steady dynamic area with two or more bits, and the host system 10 determines, for an element of a display image to be displayed on the display unit 30, whether or not to define the display area of ​​the element as a steady dynamic area based on information regarding the dynamic characteristics of the element.

[0072] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to the above embodiment, and the present invention also includes designs that do not deviate from the gist of the present invention. The configurations described in the above embodiment can be combined in any combination. [Explanation of symbols]

[0073] S1...information processing system, 10...host system, 12...processor, 14...main memory, 20...chipset, 22...auxiliary storage medium, 30...display unit, 32...timing controller, 34...EPD panel, 40...input device, 102...OS processing unit, 104...application execution unit, 106...mode setting unit, 108...graphics processing unit, 322...quantization unit, 324...dithering unit, 326...driving signal generation unit

Claims

1. An information processing system comprising a host system and a display unit, The display unit comprises: A controller and an electrophoretic display panel are provided, The controller: With respect to the electrophoretic display panel, pixels arranged in a stationary dynamic region where display contents constantly change dynamically are driven with one bit, and pixels arranged in a non-stationary dynamic region are driven with two or more bits; The host system includes: Detect an updated region that has been updated from a previous frame from a display image of the current frame; An update region that occurs at a frequency equal to or greater than a predetermined frequency within a predetermined period up to the current frame and has a common region equal to or greater than a predetermined size is selected as the stationary dynamic region. Information processing system.

2. The host system includes: The update region having a size equal to or smaller than a predetermined size is excluded from candidates for the stationary dynamic region. The information processing system according to claim 1 .

3. The host system includes: When an area ratio of a candidate region that is a candidate for the steady dynamic region to the displayed image exceeds a predetermined area ratio, The entire display image is defined as the stationary dynamic region. The information processing system according to claim 1 .

4. The host system includes: If the area ratio of the stationary update region to the candidate region that is a candidate for the stationary dynamic region is equal to or less than a predetermined area ratio of the update region, Detecting edges from the candidate regions; Among the image regions surrounded by the edges, an image region in which the gradation changes with a frequency equal to or greater than a predetermined frequency within a predetermined period up to the current frame is defined as the stationary dynamic region; An image region in which the gradation does not change within a predetermined period up to the current frame is excluded from the stationary dynamic region. The information processing system according to claim 1 .

5. A host system is provided. A display unit including a controller for driving pixels arranged in a stationary dynamic region where display content constantly changes dynamically with one bit and pixels arranged in a non-stationary dynamic region with two or more bits for an electrophoretic display panel. An information processing device that displays a display image, The host system includes: Detect an updated region that has been updated from a previous frame from a display image of the current frame; An update region that occurs at a frequency equal to or greater than a predetermined frequency within a predetermined period up to the current frame and has a common region equal to or greater than a predetermined size is selected as the stationary dynamic region. Information processing device.

6. A control method in an information processing system including a host system and a display unit, comprising: The display unit comprises: A controller and an electrophoretic display panel are provided, The controller: With respect to the electrophoretic display panel, pixels arranged in a stationary dynamic region where display contents constantly change dynamically are driven with one bit, and pixels arranged in a non-stationary dynamic region are driven with two or more bits; The host system, Detect an updated region that has been updated from a previous frame from a display image of the current frame; An update region that occurs at a frequency equal to or greater than a predetermined frequency within a predetermined period up to the current frame and has a common region equal to or greater than a predetermined size is selected as the stationary dynamic region. Control methods.

Images