JP2010049317A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device allowing a user to select and switch thumbnail images by simple operation, and displaying image data quickly without annoying the user even when there is a restriction on capacity of a memory used as a back buffer for the image data. <P>SOLUTION: A microcomputer 26 reads image data in the USB memory and displays it on a display part 17 of the display device, which displays the thumbnail image of the image data in the USB memory and displays the image data in accordance with the selection of the thumbnail image. When the last section in a sequence of the image data is focused, thumbnail images for the screen next to the screen being displayed are generated and held in the back buffer of a RAM 27 without changing the current display. When an operation for switching to the next screen is input, the thumbnail image held in the RAM 27 is displayed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a display device, and more particularly, to a display device that performs image selection using a thumbnail image and displays the selected image.

For example, from a large number of image data recorded on a PC (personal computer), a recorder, etc., desired image data is presented as a list, the user selects desired image data from the presented image data, and the selected image data A technique capable of displaying is known. Such a technique is also implemented in information terminals such as mobile phones.
In general, image data stored in various portable storage media can be displayed on a display device. Such a function is also realized in a display device such as a television.

  As a method of taking a list of image data recorded in an external memory of a portable storage medium and displaying it as a list, for example, a thumbnail included in a file of image data (image data main body) stored in the external memory Images or thumbnail images generated from the image data are displayed in a list on the display screen of the display device, and an arbitrary image selection by a user operation is accepted from the displayed thumbnail images, and the selected thumbnail image is displayed. Some image data (image data body) is displayed on a display screen.

  There is also a display device having a function of reading image data from an external memory and displaying each image as a slide show. When performing a slide show, it is necessary to read and display image data one by one from the external memory, or to read all image data recorded in the external memory when the external memory is inserted.

With regard to a technique for reading and displaying image data from an external memory, for example, Patent Document 1 displays the contents of a portable recording medium as a slide show without making the user aware of the time for reading the image data from the portable recording medium. An image reproducing apparatus is disclosed. This image reproducing apparatus detects that a portable recording medium is loaded, reads a directory and a still image data file from the portable recording medium, and writes them in a temporary storage area. Then, album information of an album corresponding to the directory is created and added to the album list, and photo information of a photo corresponding to the still image data file is created and added to the photo list. Furthermore, the photo corresponding to the still image data file is displayed by appropriately reading the album list and the photo list.
JP 2005-79822 A

  When displaying image data recorded in an external memory or the like as a list on a display device such as a television as thumbnail images, the display device usually displays a predetermined number of thumbnail images on one screen. If the thumbnail images of the image data recorded in the external memory cannot be displayed on one screen, the thumbnail display screen is switched according to a predetermined user operation, and the image data that cannot be displayed on the first screen To display a list of thumbnail images. Then, a plurality of thumbnail display screens can be sequentially switched according to the number of image data in the external memory.

  The user selects an arbitrary thumbnail image from a plurality of thumbnail images displayed in a list on the thumbnail display screen, and switches the thumbnail display screen to display the next (or previous) thumbnail display screen. The operation can be executed by a predetermined operation input unit of the display device. In a display device such as a television, a remote controller is mainly used.

When an arbitrary thumbnail image is selected from thumbnail images within one screen using the TV remote control, the user moves the focus (cursor) in an arbitrary direction by operating, for example, a direction key of the remote control, By focusing on the desired thumbnail image and pressing the enter key, the image data corresponding to the thumbnail image can be displayed.
On the other hand, when switching the thumbnail display screen, for example, by operating the direction key on the remote control to move the focus to the arrow button displayed on the thumbnail display screen, and then pressing the enter key on the remote control, the thumbnail The display screen was switched.
Alternatively, some thumbnail images can be switched by operating other predetermined keys in the remote controller.

  However, when switching between thumbnail display screens, it is complicated to operate the enter key after selecting an arrow key in the screen. Also, when the thumbnail display screen cannot be switched without using other keys, the operation is difficult to understand and complicated.

  In addition, when switching the thumbnail display screen, it is desirable that a display device such as a television display the switched thumbnail display screen as soon as possible so that the user does not feel uncomfortable. At this time, if the memory of the display device and the resources of the control system are sufficient, all the thumbnail images of the image data recorded in the external memory are read in advance, or thumbnail images are generated from the read image data and backed up. By holding the data in the buffer, the target thumbnail display screen can be displayed immediately upon an instruction to switch thumbnail images by a user operation.

However, for example, in the memory on the information processing apparatus side, there is a limit to the capacity that can be used as a back buffer for image data, and when there is no ability to execute a process for preparing thumbnail images in advance as described above, a thumbnail display screen There is a problem that it takes a long time to switch.
In such a case, for example, when a user operation for switching the thumbnail display screen is performed, the display device starts reading a thumbnail image to be displayed or generates a thumbnail image to be displayed according to the switching operation. The reading of the image data is started and sequentially displayed when the display is ready. The image data is generally recorded as a compressed file such as JPEG (Joint Photographic Experts Group), and the same applies to thumbnail images. The compressed file needs to be displayed after being decompressed. Therefore, after switching the thumbnail display screen, it takes time to read and display the thumbnail image and the image data for generating the thumbnail image from the external memory, and there is a problem that the user feels troublesome. .

  This problem is the same when image data (image data main body) is sequentially selected and displayed, or when a slide show that automatically switches and displays image data is executed. In other words, when executing the process of sequentially displaying the image data on the display screen, if the display device side memory and the control system have sufficient capabilities as described above, all the image data recorded in the external memory is stored in advance. Read and hold it. However, when there is a limit to the amount of memory that can be used, it is necessary to read out images from the external memory and switch them each time when switching screens, and switching of image data does not go smoothly and is troublesome for the user. There was a problem of feeling.

  In Patent Document 1, the contents of the portable recording medium are displayed without making the user aware of the time for reading the image data from the portable recording medium. However, since all the still image data files are read and written to the temporary storage area when a portable recording medium is loaded, a comfortable operation is guaranteed when the memory capacity of the display device is limited. I can't.

  The present invention has been made in view of the above circumstances, and can select and switch thumbnail images of a large number of image data with a simple operation, and there is a limit to the capacity of a memory used as a back buffer for image data. It is an object of the present invention to provide a display device that allows a user to quickly select and switch thumbnail images and display image data without feeling troublesome.

  In order to solve the above problems, a first technical means of the present invention includes a display unit, an interface for connecting an external memory, an operation input unit that receives an operation input by a user, and image data stored in the external memory. A display control unit that performs control to display the image data on the display unit, and the display control unit generates a thumbnail image of the image data stored in the external memory, displays the thumbnail image on the display unit, and an operation input unit In a display device that selects a thumbnail image in response to an operation input to and displays image data corresponding to the selected thumbnail image on the display unit, when the display control unit generates a thumbnail image, the thumbnail image is displayed on one screen of the display unit. Processing to generate and display only a predetermined number of thumbnail images to be performed, and out of the predetermined number of thumbnail images displayed on one screen, predetermined image data is displayed. When the focus for making a selection is positioned at the end of the array, the thumbnail image for the next screen of the currently displayed thumbnail image is generated without changing the current display, and the display device When the instruction input to move the focus to the thumbnail image to be displayed on the next screen is input to the operation input unit, the thumbnail image held in the storage unit is It is characterized by being displayed.

  According to a second technical means, in the first technical means, the display control unit has a focus for performing the selection at the beginning of a predetermined arrangement of image data among a predetermined number of thumbnail images displayed on one screen. If it is located, a thumbnail image for one screen before the currently displayed thumbnail image is generated without changing the current display, stored in the storage unit provided in the display device, and operated When there is an instruction input to move the focus to the thumbnail image to be displayed on the previous one screen, the thumbnail image held in the storage unit is displayed.

  According to a third technical means, in the first or second technical means, the operation input unit includes an operation input for moving a focus in order to select one thumbnail image from a predetermined number of thumbnail images displayed on one screen. The operation input can be executed by the direction key, and the operation input for switching the thumbnail image to the next or previous thumbnail image can be executed by the direction key.

  According to a fourth technical means, in any one of the first to third technical means, when the display control unit generates a thumbnail image, is the thumbnail image of the image data recorded in the external memory read out and used for generation? Alternatively, in the case of image data without a thumbnail image, the image data itself is read out to generate a thumbnail image from the image data, or image data that cannot be displayed on the display unit when generating the thumbnail image. In some cases, the thumbnail image of the image data that cannot be displayed is displayed to clearly indicate that it cannot be displayed.

  In the fifth technical means, when any one of the thumbnail images is selected in any one of the first to fourth technical means and image data corresponding to the selected thumbnail image is displayed on the display unit. The display control unit reads out the next image data from the external memory according to a predetermined arrangement of the image data, expands it, and stores and holds it in the storage unit.

  A sixth technical means includes any one of the first to fourth technical means, wherein the display control unit has a slide show execution function for sequentially displaying the image data stored in the external memory on the display unit. When one image data is displayed on the display unit during execution, the next image data is read out from the external memory according to a predetermined arrangement of image data, expanded, and stored in the storage unit. It is a thing.

  The seventh technical means is an image in which, in the fifth or sixth technical means, when the display control unit reads out the next image data from the external memory and develops it, the image data to be developed cannot be displayed on the display unit. In the case of data, the image data next to the image data that cannot be displayed is developed and stored in the storage unit.

  According to the present invention, selection and switching of thumbnail images of a large number of image data can be executed with a simple operation, and even when there is a limit on the capacity of a memory used as a back buffer for image data, selection and switching of thumbnails and image data are possible. It is possible to provide a display device that can promptly execute the display without feeling troublesome for the user.

FIG. 1 is a block diagram showing a configuration example of a display device of the present invention, and shows an example in which the display device of the present invention is applied to a liquid crystal television provided with a digital tuner.
In a liquid crystal television, a received signal of a digital broadcast received by an antenna 10 is selected by a tuner unit 11 and demodulated by a demodulation unit 12. The video signal of the demodulated digital broadcast signal is decoded by the video decoder 14, and the audio signal is decoded by the audio decoder 18.

  The video signal decoded by the video decoder 14 is subjected to image quality correction by the image quality correction unit 15 and displayed on the display display unit 17. The image quality correction unit 15 processes the decoded video signal and outputs a video signal to be displayed on the display display unit 17. Here, necessary video processing (for example, color space conversion processing, IP conversion processing, scaling processing, FRC processing, γ correction processing, color correction processing, synchronization detection processing, etc.) is performed according to the format of the input video signal. The

The display display unit 17 includes a liquid crystal panel and a backlight, and performs video display based on the video signal output from the image quality correction unit 15. The display display unit 17 corresponds to the display unit of the present invention.
The backlight control unit 22 controls the brightness of the backlight of the display display unit 17 in accordance with an instruction from the microcomputer 26.

  An OSD (on screen display) control unit 13 performs control to generate an OSD signal to be displayed on the display display unit 17 based on an OSD signal generation instruction from the microcomputer 26. Further, control is performed to generate an OSD signal according to the OSD information of the data signal included in the broadcast signal of the received broadcast channel. Examples of information displayed by the OSD signal include a cursor for performing a selection operation on the screen, a menu for various settings, an EPG (Electronic Program Guide), a CH (channel) call, and the like. The cursor corresponds to the focus of the present invention, and the position where the cursor is is the position where the focus is placed.

  The audio signal decoded by the audio decoder 18 is subjected to sound quality correction by the sound quality correction unit 19, is D / A converted by the D / A conversion unit 20, and is output by the speaker 21.

  The microcomputer 26 is a control means for controlling each part of the liquid crystal television. The ROM 28 holds programs and various data for controlling the operation of the liquid crystal television, and the microcomputer 26 performs control using these programs and data. The RAM 27 is used for temporary storage of data, and is also used as a work area during program execution. The RAM 27 functions as a back buffer for thumbnail images and image data bodies read out from a USB (Universal Serial Bus; hereinafter referred to as USB) memory and developed.

  The OPC sensor 25 is a sensor that detects the brightness around the liquid crystal television. In the mode in which the output of the OPC sensor 25 and the backlight are linked, the microcomputer 26 controls the backlight control unit 22 to change the light emission luminance of the backlight according to the brightness detection result detected by the OPC sensor 25. . Further, the microcomputer 26 may perform control such that the brightness of the backlight is converted according to a video feature amount such as APL (Average Picture Level) of the input video signal.

An indicator LED (Light Emitting Diode) control unit 24 controls light emission of an LED provided as an indicator in the liquid crystal television. An RTC (real-time clock) 29 is a clock that keeps the current time even when the power of the liquid crystal television is turned off.
The R / C receiver 23 receives a control code signal transmitted from a remote controller (not shown) and sends it to the microcomputer 26. The microcomputer 26 performs predetermined control according to the control code signal sent from the R / C receiver 23. The remote control corresponds to the operation input unit of the present invention.

  The USB interface 30 is an interface for mounting a USB memory so that data can be read / written. It is also possible to connect a USB hub having a plurality of ports.

  In the display device, the image data can be read from the USB memory attached to the USB interface 30 and displayed on the display display unit 17 under the control of the microcomputer 26. At this time, the thumbnail images of the image data recorded in the USB memory can be read and the thumbnail images can be displayed as a list. If there is no thumbnail image in the image data, the image data itself is read to generate a thumbnail image. When generating a thumbnail image under the control of the microcomputer 26, the thumbnail image of the image data recorded in the USB memory is read and used to generate a thumbnail image, or in the case of image data having no thumbnail image, the image data itself is used. A thumbnail image is generated from the read image data.

  Further, when a specific thumbnail image is selected by a user operation from the thumbnail display screen, image data (image data body) read from the USB memory is displayed on the display display unit 17. Here, the display control unit of the present invention that performs control for reading out image data from the USB memory and displaying the image data on the display display unit 17 is realized by the function of the microcomputer 26.

  Image data (including thumbnails) recorded in a USB memory is usually recorded as compressed data such as JPEG. In the microcomputer 26, thumbnail images and image data (image data main body) are read out, expanded (decompressed), held in the RAM 27, and displayed on the display display unit 17. A program for development is held in the ROM 28, and the microcomputer 26 uses the program to develop thumbnail images and image data (image data main body) read from the USB memory. The RAM 27 that holds the image data main body and the thumbnail image corresponds to a storage unit in the present invention.

Here, in the liquid crystal television of this embodiment, there is a limit to the capacity of the RAM 27 that can be used to store thumbnail images and image data bodies read from the USB memory, and a plurality of image data is recorded in the USB memory. In this case, it is assumed that all the image data cannot be read first and developed in the RAM 27.
For example, it is assumed that a RAM area dedicated to image processing of a USB memory is set as a part of the illustrated RAM 27, and the usable RAM capacity is limited. For example, it is assumed that a storage area for about two pieces of image data is prepared in this RAM area. Such a configuration has an advantage that a simple structure with reduced manufacturing costs can be realized.

In the configuration as described above, the microcomputer 26 displays the thumbnail image and image data to be displayed next so that the user does not feel uncomfortable when the thumbnail display screen and image data are displayed and the display screen is switched. Is read from the USB memory and developed in the RAM 27. Here, when thumbnail images and image data are displayed on the display unit 17, thumbnail images and image data that may be displayed next by a user operation, or image data to be displayed next by a slide show, The data is read from the USB memory and expanded in the RAM 27. Thereby, when a user operation is performed or when image data is switched in a slide show, the image data developed in the RAM 27 can be displayed immediately.
In the configuration of the present embodiment, even when the memory capacity is limited as described above, it is possible to quickly perform selection and switching of thumbnail images and display of image data without causing the user to feel bothered. it can.

Further, in the present embodiment, an operation input for moving the focus in order to select a specific thumbnail image from among the thumbnail images displayed on one screen can be executed by a direction key provided on the remote controller. The operation input for switching the thumbnail image to the next or previous thumbnail image can be executed with the same direction key. For example, the focus can be moved to the left and right by the left and right direction keys in one screen.
When the image data selected from the thumbnails is displayed as a single picture, the same direction key is operated to display a single picture of the next image data.

Hereinafter, an operation example of the liquid crystal television will be described more specifically.
First, a thumbnail display process in the liquid crystal television according to the embodiment of the present invention will be described. The liquid crystal television of this embodiment is provided with a plurality of external input terminals for enabling input from an external device, and an operation for switching the input of the external input terminals is possible. As the external input terminal, a D terminal, an S terminal, a video terminal, an HDMI terminal, or the like is applicable. In this embodiment, a USB input terminal (USB interface) is provided as one of external inputs.

  For example, the screen of FIG. 2 is an example of an input switching screen displayed on the liquid crystal television by the OSD. TV, EXT1 to EXT7 (external input), and USB are set as switchable inputs. The user can read image data from the USB memory by selecting USB using the operation keys of the remote controller. Here, for example, a dedicated input switching button is provided for the remote control, and the input can be switched by operating this button. At this time, when a USB memory is not attached to the USB input terminal, the USB display portion in FIG. 2 is hatched and cannot be selected.

FIG. 3 is a flowchart for explaining an example of thumbnail display processing in the liquid crystal television according to the embodiment of the present invention. The following display processing is mainly executed under the control of the microcomputer 26 of the liquid crystal television.
When USB is selected by a user operation from the menu of FIG. 2, a USB top screen is displayed (step S1). On the USB top screen, either a photo mode (PHOTO MODE) or an audio mode (AUDIO MODE) can be selected as a use mode of data recorded in the USB memory. Here, when the photo mode is selected by a user operation, the photo mode is started (step S2).

  In this case, the photo mode is started by switching the menu input and selecting the photo mode. However, when the USB memory is attached to the USB input terminal, the display automatically shifts to the USB top screen display, and the photo mode or An operation for selecting an audio mode may be enabled.

  When the photo mode is started, the liquid crystal television extracts a file list of files stored in the USB memory (step S3). In this case, only a file in a predetermined format, for example, a JPEG file (file with extension “jpg”) is searched, and the file name of the file is extracted and read. In the liquid crystal television, the total number of pages is calculated from the number of files extracted from the USB memory (step S4). The total number of pages corresponds to the number of display screens used to display a list of thumbnails for each extracted file. When displaying thumbnail images, the number of thumbnail images displayed in one screen is determined in advance. Based on the number of displays in one screen and the number of files extracted from the USB memory, the number of screens (number of pages) for displaying thumbnail images of all files is calculated.

  Next, in the liquid crystal television, the files extracted from the USB memory are sorted (step S5), and the thumbnail images of the JPEG file are displayed in the sort order (step S6). The sorting at this time can be made, for example, in the order of entry of image data in the directory (order of recording date). Alternatively, the file names may be sorted in the order of ABC, or may be performed based on other predetermined attribute information. An example of the thumbnail image display process will be specifically described below.

FIG. 4 is a flowchart for explaining an example of a thumbnail image display process.
When the thumbnail image display process is started following the process of FIG. 3, the liquid crystal television determines whether a thumbnail image exists in the corresponding file (step S11). The corresponding file refers to a file to be subjected to drawing (generation) processing of a thumbnail image to be displayed when displaying the thumbnail image of the JPEG image for the first screen.
If a thumbnail image exists in the corresponding file, the thumbnail image is drawn at high speed (step S12). That is, since the thumbnail image is included in the JPEG file of the image data, the thumbnail image can be drawn at a high speed by reading and developing the thumbnail image.

  On the other hand, if there is no thumbnail image in the file in step S11, the liquid crystal television reads out the image data body from the USB memory and expands it, and reduces it to the thumbnail size (step S13). This process needs to be reduced after the entire development of the image data main body, and is a low-speed process.

  After the high-speed thumbnail drawing process in step S12 or the low-speed thumbnail drawing process in step S13, it is determined whether or not drawing of thumbnail images for all the files has been completed (step S14). If the drawing of the thumbnail image is not completed, the process returns to step S11 to perform the drawing process of the thumbnail image of the next relevant file. When the drawing of the thumbnail image is completed, a thumbnail display screen showing a list of thumbnails is displayed (step S15).

  Then, when a specific thumbnail image is selected by a user operation on the thumbnail display screen (that is, the focus is placed on the specific thumbnail) and the enter key is pressed, JPEG image data corresponding to the selected thumbnail image is displayed. It is displayed as a picture (step S16). On the thumbnail display screen, when a specific thumbnail image is selected by a user operation and an operation for designating a slide show is further performed, a JPEG slide show is executed (step S17).

  FIG. 5 is a diagram illustrating an example of a thumbnail display screen. In this example, twelve thumbnail images can be displayed on one screen, but a folder icon is displayed together with thumbnail images of image data. As in the example of FIG. 5, the thumbnail display screen 100 displays a folder icon 101 indicating the current folder name, and a subfolder icon 102 if there is a subfolder. Then, the thumbnail image 103 is displayed in the remaining display area. The arrangement order of the thumbnail images 103 is, for example, the order of entries in the directory, arranged in the horizontal direction from the upper left, and arranged in the rows from the left to the right, and the lower right corner is determined in advance so as to be the end of the arrangement. The display size of the thumbnail image is, for example, an image size of 320 × 420 (dot) 4: 3 (W: H), and thumbnail images other than 4: 3 are displayed so as to fit within this size. .

  In the thumbnail display screen 100, only the JPEG file is extracted from the USB memory and displayed. If the image data of the thumbnail image cannot be displayed on the display display unit 17, the thumbnail display screen 100 The x mark 104 is displayed on the corresponding part. Image data that cannot be displayed is a JPEG file that is out of standard or whose contents (data) are broken. Non-standard means that the JPEG file is a standard that cannot be displayed on this liquid crystal television. Further, even when the image data capacity is larger than a predetermined upper limit capacity or when the pixel size (image data size) exceeds a predetermined upper limit value, display is impossible.

  Thus, when displaying thumbnail images, if it is determined that the image data cannot be displayed on the display display unit 17, the microcomputer 26 displays the thumbnail display screen clearly indicating that it cannot be displayed. The x mark 104 is an example of a form that clearly indicates that display cannot be performed, and a display method of another form can be applied as appropriate.

  On the thumbnail display screen 100, when the user operates the remote controller to move the focus to an arbitrary position and select it, the image data of the selected thumbnail image can be displayed as a single picture. When selecting a thumbnail image, an operation input for moving the focus in order to select a specific thumbnail image from among the thumbnail images displayed on the thumbnail display screen 100 can be executed by a direction key provided on the remote control. ing. The remote control is provided with four direction keys, left and right, up and down, and a decision key. The focus can be moved in the thumbnail display screen 100 with these four direction keys.

  Then, when selecting a thumbnail image with focus and displaying image data of a single picture, the user presses a determination key on the remote controller. As a result, a full-screen display of a single picture is performed. Further, when there are a plurality of thumbnail display screens 100, an operation for switching the current thumbnail display screen to the next or previous thumbnail display screen can be executed with the same direction key. Here, on the thumbnail display screen 100, when the focus is on the thumbnail image in the lower right corner, which is the last entry array, the thumbnail display image of the next page is displayed by further operating the right arrow key. Can do. On the thumbnail display screen of the next page, the focus is displayed on the upper left thumbnail image which is the first of the arrangement in the screen.

  Similarly, when the focus is on the upper left thumbnail image in the first entry arrangement direction, the thumbnail display screen of the previous page can be displayed by further operating the left direction key. On the thumbnail display screen of the previous page, the focus is displayed on the lower right thumbnail image which is the last of the arrangement in the screen. However, the example of FIG. 5 is the thumbnail display image of the first page, and there is no thumbnail display image of the previous page, and therefore it is impossible to switch to the previous page.

  In this way, by selecting the thumbnail image on the thumbnail display screen and switching the page of the thumbnail display screen by using the same direction key provided on the remote control, the user feels bothered in selecting the thumbnail image. It can be executed with simple operation.

  FIG. 6 is a diagram showing a full-screen display example of a single picture displayed by selecting a thumbnail image. When a thumbnail image is selected and determined on the thumbnail display screen as shown in FIG. 5, image data of a single picture as shown in FIG. 6 can be displayed. In this display state, when the user further operates the right direction key, the image data corresponding to the next thumbnail image displayed on the thumbnail display screen can be displayed in full screen as a single picture. Similarly, if the left key is operated, the image data corresponding to the previous thumbnail image displayed on the thumbnail display screen can be displayed in full screen as a single picture.

  In this case, the image data for which the x mark 104 is displayed on the thumbnail display screen 100 is skipped even when the image data is switched by operating the direction key in the single picture display state as shown in FIG. To display the next image data.

  In the configuration according to this embodiment, the microcomputer 26 reads the next thumbnail image to be displayed from the USB memory and expands it in the RAM 27 so that the user does not feel uncomfortable when switching the thumbnail display screen. Execute the process. Here, when a thumbnail image or image data is being displayed on the display display unit 17, a thumbnail image that may be displayed next by a user operation is read from the USB memory and developed in the RAM 27.

  When switching the thumbnail display screen, as described above, when the focus is on the thumbnail image in the lower right corner which is the last entry array in the thumbnail display screen 100, by further operating the right direction key, The thumbnail display screen for the next page can be displayed. Further, when the focus is on the upper left thumbnail image in the first entry arrangement direction, the thumbnail display screen of the previous page can be displayed by further operating the left direction key.

  In other words, in this example, when the focus is on the thumbnail image in the lower right corner, the thumbnail display screen of the next page is likely to be selected. Therefore, the microcomputer 26 prefetches the thumbnail display screen data of the next page from the USB memory and develops it in the RAM 27 when the focus moves to the thumbnail image in the lower right corner. Thereby, when an instruction to display the thumbnail display screen of the next page is given by the user operation, the thumbnail display screen developed in the RAM 27 can be displayed immediately. Similarly, the microcomputer 26 pre-reads the thumbnail display screen data of the previous page from the USB memory at the time when the focus moves to the thumbnail image in the upper left corner, and develops it in the RAM 27, so that it is immediately according to the user operation. The thumbnail display screen of the previous page can be displayed. As described above, according to the configuration of the present embodiment, even when the memory capacity is limited, it is possible to quickly select and switch thumbnail images without causing the user to feel bothered.

  Further, in the present embodiment, in a state where a single picture as shown in FIG. 6 is displayed, the microcomputer performs a process of prefetching the next image data from the USB memory, and developing and holding it in the RAM 27. This process is similarly performed in the case of a slide show. As a result, when an instruction to switch image data is given by a user operation or when image data is switched in a slide show, the image data developed in the RAM 27 can be displayed immediately.

  Further, when the image data is pre-read as described above and expanded in the RAM 27, the image data for which the x mark 104 is displayed on the thumbnail display screen 100 is skipped without pre-reading. The next image data is pre-read from the USB and developed. If it is found that the thumbnail image can be displayed and cannot be displayed at the stage of prefetching the image data, the image data is skipped and the next image data is prefetched.

  In other words, when displaying the image data corresponding to the selected thumbnail image or displaying the image data in a slide show, the microcomputer 26 reads out the image data to be displayed next from the USB memory and expands it. And stored in the back buffer of the RAM 27. When the microcomputer 26 reads out the image data from the USB memory and expands it, if the image data arranged next is image data that cannot be displayed on the display display unit 17, the image data that cannot be displayed is skipped. The image data that can be displayed on the display unit 17 is expanded as image data to be displayed next, and is stored and held in the back buffer of the RAM 27.

FIG. 7 is a flowchart for explaining an example of processing when a single picture of image data is displayed. When a specific thumbnail image is selected by a user operation on the thumbnail display screen, the microcomputer 26 starts displaying a single picture of the selected image data.
Here, first, JPEG image data is drawn so as to fit on the screen to be displayed (step S21), and the display of a single picture is completed (step S22). When the left key of the direction key is operated, a single picture of the previous JPEG image data is displayed (step S23). If the right key of the direction key is operated, a single picture of the next JPEG image data is displayed (step S24). In this case, it is possible to display the image data pre-read and developed in the RAM 27.

  Further, when the return key is operated in a single picture display state, the thumbnail display screen is restored. Furthermore, image rotation processing can also be assigned to a specific operation key in a single picture display state. For example, when there are keys for assigning a specific operation to the remote control (red key and green key), when the red key is operated, the image data is rotated 90 degrees to the left (step S26), and the green key is displayed. When is operated, the image data is rotated 90 degrees to the right and displayed (step S27).

FIG. 8 is a flowchart for explaining an example of processing when sequentially displaying single images of image data by a slide show. When a specific thumbnail image is selected by a user operation on the thumbnail display screen and a slide show is instructed, the microcomputer 26 starts a slide show from the selected image data.
Here, first, the microcomputer 26 displays the first JPEG image data as a normal single picture (step S31). At this time, if there is a slide show BGM, the BGM is reproduced repeatedly.

  Then, the display of the first picture is completed (step S32), and it is determined whether or not the next JPEG image data is valid image data (step S33). Effective image data is not out-of-standard or broken image data or the like, but is image data that can be displayed on the display unit 17. If the image data is not valid, the JPEG image data is skipped and the next JPEG image data is selected (step S36), and the process returns to step S33 again to determine whether or not the selected image data is valid. To do.

If the image data is valid in step S33, the next valid JPEG image data is rendered in the back buffer while displaying a single picture of the image data (step S34). That is, the next image data is pre-read and expanded, and held in a RAM prepared as a back buffer.
When the drawing to the back buffer is finished, the image data in the back buffer is transferred to the display display unit 17. Thereafter, the process returns to step S33 and the process is repeated until the slide show of all target image data is completed.

FIG. 9 is a diagram for explaining the configuration of a JPEG file.
A JPEG file can be roughly considered to be composed of four elements: a JPEG header, an EXIF header, thumbnail data, and image data (image data body). The JPEG header stores basic JPEG information such as the size of image data (for example, 1600 × 1200). The EXIF header stores information specific to the camera, such as the shooting date of a photograph recorded as image data, ISO sensitivity, and shutter speed. The thumbnail is a JPEG image obtained by reducing the image data body to a size of 160 × 120, for example. The image data body is a JPEG image itself. Among these elements, the essential elements are the JPEG header and the image data body.

From these facts, the JPEG file can have four configurations shown in FIGS. 9A to 9D. File 1 includes a thumbnail, an EXIF header, a JPEG header, and an image data body. File 2 includes an EXIF header, a JPEG header, and an image data body. File 3 includes a thumbnail, a JPEG header, and an image data body. File 4 includes a JPEG header and an image data body.
In the case of JPEG data having no thumbnail, after the entire image data body has been fully developed, the image data is reduced to generate a thumbnail image.

  In the above example, the example of processing for extracting and displaying only the JPEG file from the external memory has been described. However, a file having a format different from that of JPEG may be applied. For example, a process of displaying image data for ZIP, LZH, GIF, PNG, or other specific files may be performed.

It is a block diagram which shows the structural example of the display apparatus of this invention. It is a figure which shows an example of the input switching screen displayed by OSD on the liquid crystal television of embodiment of this invention. It is a flowchart for demonstrating the example of a thumbnail display process in the liquid crystal television of embodiment which concerns on this invention. It is a flowchart for demonstrating the example of a display process of a thumbnail image. It is a figure which shows an example of the display screen of a thumbnail. It is a figure which shows the example of a full-screen display of the single picture displayed by selection of a thumbnail image. It is a flowchart for demonstrating an example of a process when displaying the single image of image data. It is a flowchart for demonstrating an example of a process when displaying one picture of image data sequentially by a slide show. It is a figure for demonstrating the structure of a JPEG file.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Tuner part, 12 ... Demodulation part, 13 ... Control part, 14 ... Video decoder, 15 ... Image quality correction part, 17 ... Display display part, 18 ... Audio decoder, 19 ... Sound quality correction part, 20 ... D / A conversion part , 21 ... Speaker, 22 ... Backlight control unit, 23 ... R / C receiving unit, 24 ... Control unit, 25 ... OPC sensor, 26 ... Microcomputer, 27 ... RAM, 28 ... ROM, 30 ... USB interface, 100 ... Thumbnail Display screen 101. Folder icon 102 102 Subfolder icon 103 103 Thumbnail image 104 104 X mark.

Claims (7)

A display unit, an interface for connecting an external memory, an operation input unit for receiving an operation input by a user, and a display for performing control for reading out the image data stored in the external memory and displaying the image data on the display unit A control unit, and the display control unit generates a thumbnail image of the image data stored in the external memory and displays the thumbnail image on the display unit, and selects a thumbnail image according to an operation input to the operation input unit, In the display device for displaying the image data corresponding to the selected thumbnail image on the display unit,
When generating the thumbnail image, the display control unit performs a process of generating and displaying a predetermined number of thumbnail images to be displayed on one screen of the display unit, and the predetermined number of thumbnail images displayed on the one screen. If the focus for making the selection is located at the end of the array of image data, the thumbnail image for the next screen of the currently displayed thumbnail image without changing the current display Is generated and stored in the storage unit included in the display device, and when there is an instruction input to move the focus to the thumbnail image to be displayed on the next one screen to the operation input unit, A display device that displays thumbnail images stored in the storage unit.   2. The display device according to claim 1, wherein, when the focus is located at the beginning of an array of the image data among a predetermined number of thumbnail images displayed on the one screen, the display control unit Without changing the display, a thumbnail image for one screen before the currently displayed thumbnail image is generated and stored in a storage unit included in the display device, and the previous operation input unit is stored in the operation input unit. A display device that displays a thumbnail image held in the storage unit when an instruction to move the focus is input to a thumbnail image to be displayed on one screen.   The display device according to claim 1 or 2, wherein the operation input unit includes an operation input for moving the focus in order to select one thumbnail image from a predetermined number of thumbnail images displayed on the one screen. A display device characterized in that it can be executed by a direction key and an operation input for switching the thumbnail image to the next or previous thumbnail image can be executed by the direction key.   4. The display device according to claim 1, wherein, when generating the thumbnail image, the display control unit reads a thumbnail image of image data recorded in the external memory and uses the thumbnail image for the generation. Alternatively, in the case of image data without a thumbnail image, the image data itself is read and a thumbnail image is generated from the image data, or an image that cannot be displayed on the display unit when the thumbnail image is generated A display device characterized in that, in the case of data, a display that clearly indicates that the data cannot be displayed is performed.   5. The display device according to claim 1, wherein the display control unit selects one of the thumbnail images and displays image data corresponding to the selected thumbnail image on the display unit. When this is the case, the image data to be displayed next is read from the external memory, expanded, and stored in the storage unit.   5. The display device according to claim 1, wherein the display control unit has a slide show execution function for sequentially displaying the image data stored in the external memory on the display unit, and executes the slide show. A display device characterized in that when one image data is displayed on the display unit, the image data to be displayed next is read out from the external memory, expanded, and stored in the storage unit .   The display device according to claim 5 or 6, wherein when the display control unit reads out the image data from the external memory and develops the image data, the image data arranged next cannot be displayed on the display unit. In the case of data, the image data that cannot be displayed is skipped, the image data that can be displayed on the display unit is developed as the image data to be displayed next, and stored in the storage unit. Display device.

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