Information processing system, controller, and control method

Abstract

To improve subjective quality of an entire display image.SOLUTION: An information processing system provided herein comprises a host system and a display unit. The display unit includes a controller and an electrophoretic display panel. The host system is configured to determine a dynamic region, or a region where display content dynamically fluctuates, in display content to be displayed on the display unit. The controller is configured to set a drive mode, in which responsiveness is higher for the dynamic region than for a non-dynamic region, as a drive mode for the electrophoretic display panel.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Electrophoretic displays (EPDs) consume no power while displaying static content, making it possible to display a variety of information with low power consumption. EPDs are sometimes used to display information primarily consisting of text. For example, Patent Document 1 describes applications of EPDs to e-book readers, electronic medical records, electronic newspapers, and the like. EPDs are also known as electric paper displays, electronic ink displays, and the like.

[0003] However, EPDs have slower response times to display changes than other types of display devices, such as liquid crystal displays (LCDs) and organic light-emitting diode (OLED) displays. This delay tends to be particularly noticeable when expressing gradations using multiple bits. A typical EPD responds in approximately 100 ms when displaying two levels of gradation using one bit of gradation, but reaches 500 ms when displaying 16 levels of gradation using four bit of gradation. Generally, the greater the gradation bit depth, the smoother the gradation an EPD can display, but the slower its response time.

[0004] In addition, when an EPD is used with 4-bit gradation, a process called refresh is often required. This process temporarily gathers black or white particles moved to intermediate positions at both ends of the electrophoretic electrodes to display multiple gradations. This process results in a display of white or black that is unrelated to the actual required gradation. Therefore, when displaying video content on a 4-bit gradation EPD, unnecessary white or black is displayed during slow response, which can be annoying. When an EPD is used with 1-bit gradation, refresh is not required. Therefore, when using an EPD, 1-bit gradation operation is preferred even at the expense of smooth gradation for content with frequent changes (such as video or web browsing), while 4-bit gradation operation is often preferred for content with few changes that requires smooth gradation (such as displaying photographs or paintings). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-64421 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, in EPDs, it is often desirable to be able to switch the gradation display mode depending on the content. Some EPD systems are equipped with switches or setting interfaces that allow the user to switch the display mode. However, the operation of constantly changing the display mode in response to changes in content is cumbersome for the user. Furthermore, when different content is displayed simultaneously (e.g., a video and a photo are displayed side by side), it is impossible to achieve the desired response and smooth gradation for both content by switching the display 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 aspect of the present application comprises a host system and a display unit, the display unit comprising a controller and an electrophoretic display panel, the host system determines a dynamic area among the display content to be displayed on the display unit, where the display content changes dynamically, and the controller sets a drive mode for the dynamic area that is more responsive than a non-dynamic area as a drive mode for the electrophoretic display panel.

[0008] In the above information processing system, the controller may set a driving mode for the dynamic region having a lower bit depth than that for the non-dynamic region.

[0009] In the above information processing system, the controller may quantize the gradation values ​​of pixels included in the dynamic region with one bit, and quantize the gradation values ​​of pixels included in the non-dynamic region with two or more bits.

[0010] In the above display processing system, the 1-bit gradation value indicates either a first gradation value indicating a first gradation or a second gradation value indicating a second gradation lower than the first gradation, and the controller may distribute quantization errors of the gradation values ​​of each pixel of the display image to surrounding pixels in the dynamic region.

[0011] A controller according to a second aspect of the present application receives an instruction from a host system for a dynamic region, which is a region in which the display content to be displayed on an electrophoretic display panel changes dynamically, and sets a drive mode for the dynamic region that is more responsive than a non-dynamic region as a drive mode for the electrophoretic display panel.

[0012] A control method according to a third aspect of the present application is a control method in an information processing system having a host system and a display unit, wherein the display unit has a controller and an electrophoretic display panel, and executes a step of determining a dynamic area, which is an area in an image displayed on the display unit by the host system, where the display content changes dynamically. [Effects of the Invention]

[0013] According to the embodiment of the present application, by allowing dynamic and non-dynamic areas to coexist during a period when a display movement occurs on the EPD, it is possible to improve the subjective quality of the entire displayed image. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic block diagram illustrating an example of a hardware configuration of an information processing system according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic block diagram illustrating an example of the functional configuration of an information processing system according to an embodiment of the present invention. [Figure 3] FIG. 2 is a diagram showing a first example of an image displayed on a display unit. [Figure 4] FIG. 10 is a diagram showing a second example of an image displayed on the display unit. [Figure 5] FIG. 10 is an explanatory diagram showing an example of setting a dynamic region and a non-dynamic region. [Figure 6] FIG. 1 is an explanatory diagram illustrating an outline of a dynamic region determination method according to the present embodiment. [Figure 7] 5A and 5B are diagrams illustrating a first example of a method for determining a dynamic region according to the present embodiment. [Figure 8] 10A and 10B are diagrams illustrating a second example of a method for determining a dynamic region according to the present embodiment. [Figure 9] 10A and 10B are diagrams illustrating a third example of a method for determining a dynamic region according to the present embodiment. [Figure 10] FIG. 10 is an explanatory diagram illustrating an example of a size filter. [Figure 11] FIG. 10 is an explanatory diagram illustrating a stability filter. [Figure 12] FIG. 10 is a diagram illustrating a fourth example of a method for determining a dynamic region according to the present embodiment. [Figure 13] 10A and 10B are diagrams illustrating a method for setting a dynamic region according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present application will be described with reference to the drawings. First, an example of the configuration 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 an example of the hardware configuration of the information processing system S1 according to this embodiment.

[0016] 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 including the host system 10, the display unit 30, and the input device 40. Alternatively, the information processing system S1 may be configured such that the host system 10 is configured separately from one or both of the display unit 30 and the input device 40. 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 representing a display image according to various programs and outputs the acquired display data to the display unit 30. The host system 10 may monitor operation signals input from the input device 40 and operate based on the input operation signals. In this application, operating based on operation signals input from the input device 40 may be referred to as "operating in response to an operation," etc.

[0017] 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. An EPD device is an electrophoretic display (EPD) device with pixels that use an electrophoretic method. A display image, or simply an image, refers to the display content that appears on the screen, i.e., the spatial changes in brightness and color. A display image includes elements such as patterns, figures, symbols, characters, or a combination of some 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 one of several predetermined drive modes.

[0018] The bit depth of the gradation value representing the gradation of each pixel varies depending on the drive mode. Gradation corresponds to the brightness of that pixel, i.e., density or shade. Gradation values ​​are also called pixel values ​​or signal values. In particular, gradation values ​​related to color display are also called color signal values. Bit depth corresponds to the number of bits used to represent the gradation value. The greater the bit depth, the wider the range of gradation values, but the range of gradations represented remains the same. In other words, the gradations corresponding to the maximum and minimum gradation values ​​are the same regardless of the bit depth. The greater the bit depth, the smaller the difference in gradation between adjacent gradation values ​​(also called the gradation width). With a bit depth of 1 bit, only two gradations can be represented: the first gradation corresponding to the maximum value (e.g., 1) (e.g., black in monochrome) and the first gradation corresponding to the minimum value (e.g., 0) (e.g., white). However, while a higher bit depth allows for the representation of multiple gradations, it also reduces pixel responsiveness. When pixels are driven with a bit depth greater than 2 bits, they require a refresh process every predetermined refresh period.

[0019] The input device 40 is capable of receiving user operations and generates an operation signal in response to the received 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 used as the input device 40 may be integrated with the EPD panel 34 of the display unit 30 to form a touch panel.

[0020] As described below, the host system 10 according to this embodiment identifies, within a display image to be displayed on the display unit 30, a region in which the image constituting the display content steadily changes over time as a dynamic region. This dynamic region is sometimes referred to as a steady dynamic region. Generally, an image is expressed by a distribution of grayscale values ​​for adjacently arranged pixels at different positions, i.e., a grayscale distribution. Image fluctuations are expressed by changes in the grayscale distribution between frames. The host system 10 notifies the display unit 30 of the display image and the identified dynamic region. For the 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 for the non-dynamic region (other regions). While a decrease in image quality is acceptable for the dynamic region, high responsiveness is required. For the non-dynamic region, a decrease in responsiveness is acceptable, but high image quality is required. Therefore, both quality and responsiveness can be achieved for the entire display image, improving subjective quality.

[0021] 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.

[0022] The processor 12 controls the overall functions of the device including the host system 10. For example, one or more CPUs (Central Processing Units) are used as the processor 12. The processor 12 executes predetermined programs 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 the processing instructed by the instructions written in the program may be referred to as "executing the program" or "running the program."

[0023] 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 that are 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 the minimum system devices that make up the host system 10. The host system 10 is configured to include system devices as hardware, and software such as an OS, schedule tasks, and the like.

[0024] 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 types of 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).

[0025] 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. The auxiliary storage medium 22 may be, for example, a solid-state drive (SSD) or a hard-disk drive (HDD).

[0026] 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) 32 in accordance with an input / output method defined by a predetermined input / output standard. The input / output method may be, for example, a method defined by the DP (Display) standard, the MIPI (Mobile Industry Processor Interface) standard, or the HDMI (High-Definition Multimedia Interface) standard. The timing controller 32 quantizes the grayscale values ​​for each pixel indicated by the input display data at a bit depth corresponding to the drive mode and converts them into quantized values. The timing controller 32 generates drive signals indicating the grayscale for each pixel in accordance with the display timing of the EPD panel 34 to display each pixel at a grayscale corresponding to the converted quantized value. The timing controller 32 outputs the generated drive signals to the EPD panel 34. Depending on the drive mode, the timing controller 32 performs a refresh process at a predetermined refresh rate and sets the grayscale value to a predetermined reference value (e.g., a minimum value). The timing controller 32 may be equipped with an arithmetic circuit, such as 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.

[0027] 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 the specified gradation to the pixel corresponding to the timing specified by the drive signal input from the 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 corresponding to the voltage applied from the drive circuit. Each pixel has a pair of electrodes that hold a solution between them. Charged particles made of pigment float in the solution. The charged particles move toward the electrode of the opposite polarity to themselves in response to the applied voltage. This movement brings about a change in gradation.

[0028] Next, an example of the functional configuration of the information processing system S1 will be described. 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 108.

[0029] 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 processes 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, application startup, monitoring the execution status of applications after startup, setting a display area for application images, priority control for components of a displayed image, cursor display, etc.

[0030] The OS processing unit 102 starts an application instructed by an operation signal in response to an operation and begins execution of the application. The OS processing unit 102 may start execution of an application whose usage environment satisfies predetermined startup conditions. The startup condition may be, for example, the current time reaching a predetermined startup time (startup timer). The application image referred to above refers to a display image acquired by processing a running application. The application image is configured to be contained in a rectangular window (sometimes referred to herein as an "application window"). In response to an operation, the OS processing unit 102 performs operations such as specifying an application window to be focused on as a display target, changing the size or position of the application window on the display image, erasing, or redisplaying the application window. The OS processing unit 102 prioritizes the display of an application image that was started last or operated last among multiple application images. When prioritizing the display of a certain application image, the OS processing unit 102 displays the contents of the shared area of ​​the certain application image in a shared area shared with other application images, and discards the contents of the shared area of ​​the other application images without displaying them.

[0031] The OS processing unit 102 executes various screen displays as processing instructed by the OS. Various screen components (i.e., UI (User Interface) components) are used in the screen displays. For example, the OS processing unit 102 displays a cursor at a position on a display image instructed in response to an operation. When a position within an application image area is instructed in response to an operation, the OS processing unit 102 executes a function of the application corresponding to that position (e.g., pressing a button to turn on or off a specific function). When a position outside the application image area is instructed in response to an operation, the OS processing unit 102 executes an OS-specific function corresponding to that position (e.g., moving a data file by a drag operation). The OS processing unit 102 creates a display image to be displayed on the display unit 30 by superimposing, at a predetermined priority, element images provided by OS-specific functions and the image of the application currently being executed.

[0032] The application execution unit 104 executes an application whose launch is instructed by the OS processing unit 102. When processing an application, the application execution unit 104 constructs a display image to be displayed as a function of the application. For example, in a video playback application, a display image representing the video whose playback is instructed is constructed. The constructed display image is accommodated in an application window assigned to the application.

[0033] The mode setting unit 106 identifies dynamic regions in the display image to be displayed on the display unit 30 and distinguishes them from non-dynamic regions, which are other regions. The mode setting unit 106 monitors the grayscale distribution in the display image for each frame at different times, or the occurrence of information that may cause fluctuations in the grayscale distribution. For example, the mode setting unit 106 defines a dynamic region as a region formed by spatially connected portions where fluctuations in the grayscale distribution occur at a certain frequency or more within a predetermined period up to that point. For example, if the grayscale distribution in a dynamic region does not fluctuate within a predetermined period up to that point, the mode setting unit 106 changes the region to a non-dynamic region. As described below, the mode setting unit 106 generates a drive command including setting information indicating the portion of the display image occupied by the dynamic region. The mode setting unit 106 outputs the generated drive command to the display unit 30. As a result, the dynamic region is displayed using a drive mode different from that used for the non-dynamic region. An example of a method for determining a dynamic region will be described later.

[0034] The graphics processing unit 108 recognizes the display unit 30 connected to the host system 10. The graphics processing unit 108 generates display data that indicates the display image configured by the OS processing unit 102 for each frame. One frame of the display image is expressed by a gradation value for each pixel. The gradation value has a bit depth of, for example, 8 to 10 bits. The graphics processing unit 108 outputs the generated display image to the display unit 30, which then displays the display image. The functions of the graphics processing unit 108 may be realized by executing a graphics driver included with the OS, or by executing a device driver dedicated to the display unit 30.

[0035] 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 every time new display data is input, the stored display data is updated with the new display data. The quantization unit 322 extracts setting information from the drive command input from the host system 10, identifies the dynamic region indicated in the extracted setting information, and identifies regions other than the dynamic region as a non-dynamic region. The quantization unit 322 sets a drive mode for the dynamic region that has higher responsiveness than the drive mode for the non-dynamic region. The quantization unit 322 sets a bit depth for the dynamic region (e.g., 1 bit) that is smaller than the bit depth for the non-dynamic region (e.g., 4 bits).

[0036] The quantization unit 322 reads out the grayscale values ​​of each pixel located in the dynamic area and the non-dynamic area from the frame buffer at shorter intervals as the set bit depth becomes smaller. 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 display data.

[0037] For regions with a bit depth of 2 bits or more, the quantizer 322 notifies the drive signal generator 326 of the quantized value for each pixel in that region. This is because dithering is not performed for that region. However, the quantizer 322 performs a refresh process for the pixels in that region at predetermined refresh cycles. The refresh cycle may be set to be longer for drive modes with higher bit depths. In the refresh process, the quantizer 322 sets the quantized value for each pixel to a predetermined reference value (e.g., a quantized value corresponding to the maximum or minimum gradation), and then returns the quantized value to the original value. Each time the quantized value is changed, the quantizer 322 notifies the drive signal generator 326 of the changed quantized value.

[0038] The dithering unit 324 performs dithering in the dynamic region identified by the mode setting unit 106 to spatially disperse quantization errors resulting from quantizing display data. The dithering unit 324 identifies the dynamic region based on setting information notified by the quantization unit 322. For example, the dithering unit 324 calculates the difference between the pre-quantization gradation value and the quantized value for each pixel in the dynamic region as a quantization error, and disperses the calculated quantization error to surrounding pixels. Note that dithering does not necessarily have to be performed. For example, dithering is less necessary for content such as text that only has black and white gradations.

[0039] The quantization error can be distributed using any of a number of methods, including matrix operations using the Floyd-Steinberg matrix, matrix operations using the Atkinson matrix, and the minimum average error method. According to the matrix operations, the quantization error of the target pixel is distributed to the unprocessed pixels at a predetermined rate and added to their gradation values. Because the target pixel is changed to an unprocessed neighboring pixel each time a matrix operation is performed, the pre-quantization gradation value of the unprocessed pixel and the quantized value obtained by quantizing that gradation value are not determined until the target pixel itself becomes the target pixel. The dithering unit 324 uses the final quantization value obtained for each pixel in the dynamic range and updates the original quantization value with the newly adopted quantization value. The dithering unit 324 notifies the drive signal generation unit 326 of the quantization value of each pixel, including the updated quantization value.

[0040] 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 at a grayscale corresponding to the applied voltage. The dithering unit 324 may be omitted from the timing controller 32. In that case, the quantized value for each pixel obtained by the quantization unit 322 is notified to the drive signal generation unit 326 and used to generate the drive signal.

[0041] Next, an example of an image displayed on the display unit 30 will be described. Figures 3 and 4 show examples of images displayed in 1-bit and 4-bit modes, respectively. The 1-bit and 4-bit modes quantize gradation values ​​by 1 bit and 4 bits, respectively. Figure 4 shows more subtle changes in gradation than Figure 3. In 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, because the spatial distribution of gradation can only be expressed in an area significantly larger than the pixel spacing, image quality is degraded compared to 4-bit mode. On the other hand, 1-bit mode has higher responsiveness than 4-bit mode, allowing for more frequent updates and eliminating the need for refresh processing.

[0042] Therefore, the quantization unit 322 according to this embodiment sets a driving mode for a dynamic region that is more responsive than a driving mode for a non-dynamic region. The host system 10 defines a spatially connected region in which changes in gradation distribution occur at a frequency greater than or equal to a predetermined frequency within a predetermined period up to that point as a dynamic region, and defines other regions as non-dynamic regions. Therefore, a method with a higher responsiveness than a non-dynamic region is set for a dynamic region in which gradation changes or image movement occur frequently. For example, in the example of FIG. 5, the region including the area where the image of a moving vehicle appears at that point and the area through which the image of the vehicle passed immediately before that is set as the dynamic region da, and the surrounding area is set as the non-dynamic region na. In dynamic regions, the image changes over time, and degradation of image quality due to a coarse gradation range is tolerated. In non-dynamic regions, degradation of image quality is suppressed by a fine gradation range, and time-varying images are 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 using a single driving mode.

[0043] Next, a specific example of a method for determining a dynamic region will be described. In the following description, a case where 1-bit mode is set for the dynamic region and 4-bit mode is set for the non-dynamic region will be exemplified. The dynamic region will be referred to as a "1-bit region" and the non-dynamic region will be referred to as a "4-bit region." Figure 6 is an explanatory diagram illustrating an outline of the method for determining a dynamic region according to this embodiment.

[0044] (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 newly started is an application related to 1-bit display based on whether or not the name of the application 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 set in advance 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 video playback, image editing, or image creation.

[0045] (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 operations, etc. (Step S106) The mode setting unit 106 monitors the major motion operation status of the element images that are elements of the display image (major motion operation checker). Element images include, for example, moving images or animated images included in application images specified by an application. The major motion status includes the frequency of the motion within a predetermined period up to that point and the stability of the area where the motion occurs.

[0046] (Step S108) The mode setting unit 106 determines a 1-bit area based on the detection result of any one step or a 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.

[0047] Next, a specific example of a method for determining a dynamic area according to this embodiment will be described. Fig. 7 is a diagram showing a first example of a method for determining a dynamic area according to this embodiment. The technique illustrated in Fig. 7 corresponds to a specific example of a determination method 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 currently running in the OS processing unit 102 and that is accompanied by image display, and information about the display area for that application. (Step S204) The mode setting unit 106 excludes the display area of ​​the application having a predetermined size (for example, 200×200 pixels to 400×400 pixels) from the candidates for the dynamic area.

[0048] (Step S206) The mode setting unit 106 refers to a 1-bit application list that has been set in advance in the mode setting unit 106, and determines whether each application notified in the application name list corresponds to a 1-bit application, and excludes the display area of ​​applications that do not correspond from the candidates for the dynamic area. (Step S208) The mode setting unit 106 determines whether the number of applications with image display that are running and that have not been 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.

[0049] (Step S210) The mode setting unit 106 determines 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 determine whether the model notified in the device information input from the display unit 30 or the timing controller 32 is capable of setting multiple 1-bit regions based on whether the model includes a model listed in a pre-set model list. The ability to set multiple 1-bit regions corresponds to the ability to independently realize quantization of gradation values ​​with different bit depths for multiple partial regions included in the display area. If it is determined that the setting is possible (YES in step S210), the process proceeds to step S214. If it is determined that the setting is possible (NO in step S210), the process proceeds to step S212.

[0050] (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 currently being executed as a 1-bit area, and sets the other areas as a 4-bit area. (Step S216) Mode setting unit 106 sets the display area of ​​that one application as a 1-bit area and sets the other areas as a 4-bit area, and then ends the processing in FIG.

[0051] 8 is a diagram showing a second example of a dynamic area determination method according to this embodiment. The technique illustrated in FIG. 8 corresponds to a specific example of a determination method based on checking the OS behavior. (Step S302) The mode setting unit 106 monitors user operations that instruct a transition of the display area among the processes performed by the OS processing unit 102. A transition of the display area includes, for example, any one of the following items, such as moving a screen component displayed by the OS, or changing its size or shape, or a combination of any two or more of these items. The screen components to be monitored include windows, cursors, icons, etc.

[0052] (Step S304) The mode setting unit 106 excludes from the evaluation target screen elements any screen element whose display area size is equal to or smaller than a predetermined size (for example, 200×200 pixels to 400×400 pixels) (size filter). By excluding relatively small screen elements from the evaluation target, only 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. Then, the process of FIG. 8 ends.

[0053] FIG. 9 illustrates a third example of a dynamic area determination method according to this embodiment. The method illustrated in FIG. 9 corresponds to a specific example of a determination method based on major transition confirmation. This method aims to detect areas where changes in the grayscale distribution occur steadily (i.e., continuously for a predetermined period of time or more) in the same location. Therefore, simply designating an area where a difference occurs between the previous and current frames as a dynamic area may not solve the problem. For example, when a cursor is moved by a user or a part of a moving image changes, the difference in display mode from the surrounding area may create a sense of incongruity. Furthermore, when switching pages, the display content changes significantly before and after the page switch, making the effect of switching the drive mode ineffective. For example, even if the drive mode remains in 4-bit mode, the entire display area is rewritten by refreshing. In contrast, when the drive mode is changed from 4-bit mode to 1-bit mode, the display image is rewritten, and then the display image is rewritten again, without any change.

[0054] In this example, the mode setting unit 106 acquires an update region indicating a change in gradation or image from the previous frame to the current frame. The mode setting unit 106 uses, for example, a DR (Dirty Rectangle) region generated by a Windows® function as the update region. Because the DR region is a rectangular region that includes pixels where pixel changes have occurred, it does not necessarily coincide with the region in which the moving image is actually displayed. Furthermore, depending on the OS specifications, a DR region may be generated even when there is no actual change in the screen. 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 region of that transparent window may be reported as the DR region. Therefore, the mode setting unit 106 evaluates the stability of the DR region and adopts a DR region that is determined to be stable. Furthermore, the display region of the moving image cannot be identified solely based on the simple 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 displayed image. The mode setting unit 106 detects changes in the gradation distribution within the image region surrounded by the detected edges.

[0055] (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 step S406 and thereafter. 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, and therefore the impact on visibility is thought to be small. (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 next stability evaluation. In the example of FIG. 10, the lower right DR region that appears in the second and third frames of the period is excluded.

[0056] (Step S408) The mode setting unit 106 performs stability evaluation for each DR region (stability filter). The stability evaluation evaluates whether or not the DR regions occupy a common area that is greater than or equal to a predetermined frequency and a predetermined size within a predetermined evaluation period up to that point. However, areas where the common area is less than a predetermined size (e.g., 200 × 200 pixels to 400 × 400 pixels) are excluded from the evaluation. In the example of FIG. 11, it is determined whether or not there is an area that is greater than or equal to 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 in 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. Of these, areas that are shared over three or more frames are solid. Of these, areas that are shaded are excluded from the evaluation because the size of the shaded areas is less than the predetermined size. 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 that have 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 regions that are evaluated as stable as targets for subsequent processing, and excludes the DR regions that are not evaluated as stable from targets for subsequent processing.

[0057] (Step S410) The mode setting unit 106 determines whether or not a DR area with a predetermined ratio (for example, 70 to 90%) or more exists within the display area of ​​one application. If it is determined that such an area exists (YES in step S410), the process proceeds to step S412. If it is determined that such an area does not exist (NO in step S410), the process proceeds to step S414. (Step S412) The mode setting unit 106 determines whether or not a DR region of a predetermined ratio or more exists in the same position without moving. If it is determined that such a region exists (YES in step S412), the process proceeds to step S418. If it is determined that such a region does not exist (NO in step S412), the process proceeds to step S416.

[0058] (Step S414) The mode setting unit 106 determines the entire display area as a 1-bit area. (Step S416) The 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. The DR area determined to exist at the same position is presumed to include a moving image.

[0059] 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 dynamic region according to this embodiment. Fig. 12 shows an example of a method for determining a 1-bit region as a dynamic region in step S418 of Fig. 9. (Step S502) The mode setting unit 106 detects an image in the DR region that exists 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.

[0060] (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 horizontally or vertically oriented line segments that approximate the detected edges. The mode setting unit 106 identifies, from the identified image areas, areas that are equal to or larger than a predetermined size as candidates for 1-bit areas. 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 in which a change in gradation occurs. 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.

[0061] Next, a method for updating the dynamic region setting will be described. Fig. 13 is a diagram illustrating a dynamic region setting method according to this embodiment. The example in Fig. 13 is based on the assumption that the 1-bit mode is enabled and the 4-bit mode is disabled for the dynamic region, and the 4-bit mode is enabled and the 1-bit mode is disabled for the non-dynamic region. (Step S602) The mode setting unit 106 identifies an image area within the display image that is stationary and not moving and has a predetermined size or larger. Here, the mode setting unit 106 may use the image area determined by the processing of step S506 in FIG. 12. (Step S604) The mode setting unit 106 excludes from processing an image area in which pixel changes due to cursor movement are detected. Because pixel changes due to cursor movement are temporary and are predicted by user operation, degradation of image quality at that time is acceptable.

[0062] (Step S606) The mode setting unit 106 determines whether the 1-bit mode is valid for the identified image area, that is, whether it is set as a 1-bit area. If it is determined to be valid (step S606 YES), the process proceeds to step S610. If it is determined to be invalid (step S606 NO), the process proceeds to step S608. (Step S608) The mode setting unit 106 determines whether pixel changes have occurred in the image area 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 a pixel change has occurred at least once in the image area in a predetermined period of time (e.g., 5 to 15 frames) up to that point in time. If it is determined that a pixel change has occurred (YES in step S610), the process proceeds to step S614. If it is determined that a pixel change has not occurred (NO in step S610), the process proceeds to step S616.

[0063] (Step S612) The mode setting unit 106 enables the 1-bit mode and disables the 4-bit mode for the identified image area. (Step S614) The mode setting unit 106 does not change the drive mode for the identified image area. (Step S616) The mode setting unit 106 cancels the 1-bit mode for the identified image area and changes it to the 4-bit mode.

[0064] As described above, the information processing system S1 according to this embodiment includes a host system 10 and a display unit 30, and the display unit 30 includes a controller (e.g., timing controller 32) and an electrophoretic display panel (e.g., EPD panel 34). The host system 10 determines a dynamic region, which is a region where the display content changes, among the display content to be displayed on the display unit 30, and the controller sets a drive mode for the dynamic region that is more responsive than a non-dynamic region as a drive mode for the electrophoretic display panel. According to this configuration, pixels arranged in dynamic regions are driven in a driving mode with higher responsiveness than pixels arranged in non-dynamic regions. Therefore, in a single frame of a displayed image, dynamic regions and non-dynamic regions coexist during periods when the images constituting the displayed image move. In dynamic regions, high responsiveness to image fluctuations is possible, allowing for degradation of image quality due to quantization. In contrast, non-dynamic regions allow for display with fine gradations, and do not require responsiveness to gradation fluctuations. This improves the subjective quality perceived by the user as a whole displayed image without requiring complex operations. Furthermore, because highly responsive dynamic regions do not necessarily require refresh processing, limiting refresh processing to non-dynamic regions reduces power consumption compared to uniformly refreshing the entire display area.

[0065] This embodiment may also be implemented as follows. The controller may set a driving mode for dynamic regions with a lower bit depth than for non-dynamic regions. The controller may quantize the grayscale values ​​of pixels included in the dynamic region with one bit, and quantize the grayscale values ​​of pixels included in the non-dynamic region with two or more bits. The 1-bit gradation value may indicate either a first gradation value indicating a first gradation or a second gradation value indicating a second gradation lower than the first gradation. The controller may distribute quantization errors of the gradation values ​​of each pixel to surrounding pixels in the dynamic region.

[0066] A host system 10 specifies a dynamic area, which is an area where the display content changes dynamically, among the display content to be displayed on an electrophoretic display panel (e.g., EPD panel 34), and a controller (e.g., timing controller 32) sets a drive mode for the electrophoretic display panel that is more responsive for the dynamic area than for the non-dynamic area.

[0067] A control method in an information processing system S1 having a host system 10 and a display unit 30, wherein the display unit has a controller (e.g., a timing controller 32) and an electrophoretic display panel (e.g., an EPD panel 34), and the control method executes the steps of: determining a dynamic area, which is an area in which the display content to be displayed on the display unit 30 by the host system 10 changes; and setting a drive mode for the dynamic area that is more responsive than a non-dynamic area as a drive mode for the electrophoretic display panel by the controller.

[0068] Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configurations are not limited to the above-described embodiments, and the present invention also includes designs that do not deviate from the gist of the present invention. The configurations described in the above-described embodiments can be combined in any manner. [Explanation of symbols]

[0069] 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...drive 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 host system determining a dynamic area in which the display content to be displayed on the display unit changes dynamically; The controller A driving mode for the electrophoretic display panel is set to a driving mode that is more responsive to the dynamic area than to the non-dynamic area. Information processing system.

2. The controller A driving mode having a lower bit depth for the dynamic region than for the non-dynamic region is set. The information processing system according to claim 1 .

3. The controller quantizing the gradation values ​​of the pixels included in the dynamic region to one bit; The gradation values ​​of the pixels included in the non-dynamic area are quantized to 2 bits or more. The information processing system according to claim 2 .

4. the 1-bit gradation value indicates either a first gradation value indicating a first gradation or a second gradation value indicating a second gradation lower than the first gradation, The controller In the dynamic region, the gradation value of each pixel is distributed to surrounding pixels. The information processing system according to claim 3 .

5. A host system specifies a dynamic area, which is an area where the display content changes dynamically, among the display content to be displayed on the electrophoretic display panel; As a driving mode for the electrophoretic display panel, A drive mode that is more responsive to the dynamic region than to the non-dynamic region is set. controller.

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 host system determining a dynamic area in which the display content to be displayed on the display unit changes dynamically; The controller setting a driving mode for the electrophoretic display panel that is more responsive to the dynamic area than to the non-dynamic area. Control method.

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