KR20090086715A - Apparatus and method for displaying thumbnail image - Google Patents

Abstract

A thumbnail image display device and a method thereof are provided to change the thumbnail image of a moving picture at a preset time in case the preview function is executed in a digital device. An input unit(210) receives a command related to a preview function from a user. A memory(220) stores image data. A thumbnail image processor(230) generates a plurality of thumbnail images at preset time intervals for each image data. A display unit(240) displays the generated thumbnail image on a screen. A controller(250) displays the generated thumbnail images in a predetermined area of the screen.

Description

Thumbnail image display device and method {Apparatus and Method for displaying thumbnail image}

The present invention relates to a digital device, and more particularly, to a thumbnail image display device and a method thereof.

Recently, according to the trend of digital convergence, preview functions are provided in various digital devices having a large storage medium.

Here, a digital device is a device having a digital circuit for processing digital data, the computer, printer, digital TV, digital camera, digital copier, personal digital terminal (PDA), mobile phone, which can display image data on the screen of the product Examples include mobile multimedia players (PMPs), MP3 players, digital video recorders, and the like.

In such a digital device, image data (for example, a picture) is generally compressed and stored as a JPEG (Joint Picture Expert Group), and moving image data is compressed and stored as a Moving Picture Expert Group (MPEG).

The preview function refers to a function of displaying a small sized image, for example, a thumbnail image, in order to preview such image data or video data.

The thumbnail image represents a specific frame of the image data or the video data smaller than the original size, and the user can check the contents of the image data or the video data through the thumbnail image.

The preview function has an advantage that it is easier and easier to check and search the contents of the file compared to the text-based search method that lists only the file name or title.

1 is a diagram illustrating a screen configuration on which a conventional thumbnail image is displayed.

As shown in the drawing, a plurality of thumbnail images from # 1 to # 9 are displayed on one screen, and the thumbnail images # 1 to # 9 are displayed as only one still image.

Therefore, according to the conventional thumbnail image display method, it is not easy to distinguish a picture file from a video file.

Of course, in the case of a video file, there is a mark indicating that it is a video file in the thumbnail image. However, since the mark is small, those who are not familiar with operations on digital devices or those with poor eyes can use the mark to display a video file. It's not easy to tell if it's a file.

In addition, it is not easy to find a video that a user wants by using only one still image. For example, when a series of videos exists or when there are multiple images taken by the camera in the same place, the background screen is similar. Therefore, it is not easy to determine a video desired by the user with only one still image.

In addition, since the conventional thumbnail image display method shows only the first picture of a video, there is a lot of inconvenience in randomly playing the video. Of course, the skip function allows the user to watch the video by moving to a desired point in time, which is a hassle for the user to find the point in time.

Accordingly, an object of the present invention is to provide a thumbnail image display apparatus and method for easily distinguishing a still image from a moving image file through a preview function, and selecting a desired moving image file to play from a desired portion.

A preferred embodiment of a thumbnail image display device of the present invention devised to solve the above problems is to generate a thumbnail image of a memory for storing image data and the image data stored in the memory, and at a predetermined time interval for each of the image data. A thumbnail image processing unit for generating a plurality of thumbnail images, a display unit for displaying the generated thumbnail image on the screen, and the generated thumbnail image on a predetermined area of the screen for each image data, wherein the image is displayed in each area. And a controller configured to continuously display a plurality of thumbnail images for each data according to the preset time interval.

Here, the thumbnail image processing unit may include an I frame extraction module for extracting I frames located at predetermined time intervals for each image data stored in the memory, and after decoding the extracted I frames, scaling the corresponding images. And a thumbnail image generation module for generating a thumbnail image of the data.

According to an exemplary embodiment of the present invention, a method of displaying a thumbnail image includes selecting image data from a memory according to the number of thumbnail images set to be displayed on a screen when a thumbnail image display command is input, and displaying a thumbnail image of the selected image data. Generating a plurality of thumbnail images according to a predetermined first time interval for each image data, and displaying the generated thumbnail images on a predetermined area of the screen for each image data, wherein each of the plurality of image data for each image data is displayed. And displaying thumbnail images continuously according to the first time interval.

The generating of the thumbnail image may include extracting I frames located at the first time interval from the selected image data, decoding and scaling the extracted I frames, and generating a plurality of thumbnail images. Characterized in that comprises the step of generating.

The decoding of the extracted I frames may include converting the image data into a discrete cosine transform (DCT) coefficient, inverse quantizing the DCT coefficients, and inversely discrete the inverse quantized DCT coefficients. An inverse discrete cosine transform (IDCT) is performed. The inverse discrete cosine transform is performed by using only a value of a low frequency region of the inverse quantized DCT coefficients.

In addition, after displaying the generated thumbnail image on the screen, if a thumbnail image selection command for selecting a predetermined thumbnail image among the thumbnail images displayed on the screen is input, I is positioned at a second preset time interval in the corresponding image data. Generating a thumbnail image of a frame, and displaying thumbnail images according to the second time intervals in predetermined areas of the screen, respectively.

According to another embodiment of the present invention, a thumbnail image selection command for selecting a thumbnail image from among thumbnail images displayed on the screen is input, and a thumbnail of an I frame located at a predetermined time interval in the corresponding image data is input. Generating an image, and displaying thumbnail images according to the time intervals in predetermined areas of the screen, respectively.

According to the present invention, when the preview function is executed in the digital device, since the thumbnail image of the video is changed according to a preset time, the user can easily distinguish between the picture and the video, and can easily select the desired video.

In addition, by displaying a thumbnail image for each preset time for the video file selected by the user in the preview, the user may play back the desired video portion without any manipulation.

In addition, after extracting the I frame from the image data, a loop filtering process that does not significantly affect image quality is omitted in the process of decoding the I frame, and only the value of the low frequency region of the inverse quantized DCT coefficients is used in the DCT inverse transform process. By doing so, the amount of calculation can be greatly reduced, thereby improving the working speed.

In addition, in the present invention, when the extracted I frame is stored in a memory for decoding, the data capacity is reduced and stored in a range where there is no significant loss in image quality, and then decoding is performed. This saves time in memory and also reduces power consumption during this process.

Hereinafter, a thumbnail image display device and a method thereof of the present invention will be described in detail with reference to FIGS. 2 to 7.

In describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification.

2 is a diagram illustrating an embodiment of a thumbnail image screen of the present invention.

As shown in the drawing, a screen is divided into four areas to show thumbnail images of image data for each area. At this time, the thumbnail images are displayed on the screen continuously by changing the predetermined time unit.

Here, the same thumbnail image is displayed in the case of a still image such as the photo 130, but different thumbnail images are displayed in the case of the first to third videos 110, 120, and 140 as time passes.

In general, digital apparatuses use the Moving Picture Experts Group (MPEG) standard as a video compression method. The video frame types of the MPEG include an I frame (Intra Frame Picture), a P frame (Predicted Frame Picture), and a B frame (Bidirectional). Frame picture).

The I frame is an image frame that can be recovered by itself without requiring another reference frame, the P frame requires one reference frame decoded first in decoding order, and the B frame first according to the decoding order. It requires two decoded reference frames.

In this way, P frames and B frames should be decoded using previously decoded frames, but since I frames can be decoded using only their own information without predicting the preceding and following frames, the I frames are used as thumbnail images. Display on the screen.

That is, since the I frame can be decoded independently, unlike the P frame or the B frame, the amount of computation used for decoding is relatively small, so it is suitable for previewing.

In addition, since the file format (for example, avi, asf, mp4, k3g, skm, etc.) used for all movies has a data structure in picture units, the starting point of the picture can be known at any time. have.

Therefore, when the user selects a preview function in a digital device, the video extracts and decodes only I frames in predetermined time units, generates thumbnail images, and displays them continuously on the screen.

According to the present invention, since the preview screen of the video changes according to a preset time, the user can easily distinguish between the picture and the video, and can easily select the desired video.

At this time, since the occurrence frequency of the I frame differs according to the video, the second video 120 does not change the thumbnail image after the first unit time passes, but after the second unit time passes, the thumbnail image changes. The first video 110 and the third video 140 may see that thumbnail images change at each unit time.

Therefore, instead of extracting I frames at preset unit times to generate thumbnail images and displaying them on the screen, instead of extracting and decoding them every I frame for each movie, create thumbnail images and display them on the screen. It may be.

3 is a diagram illustrating another embodiment of a thumbnail image screen of the present invention, in which thumbnail images of one video file are divided and displayed on a screen according to a predetermined time zone according to each region.

According to the present exemplary embodiment, when a user selects a predetermined video from a video displayed on the screen through the preview function, thumbnail images according to a preset time interval for the selected video are displayed on one screen.

For example, referring to FIG. 2, when the user selects the first video 110, the thumbnail image of the first video file is divided into 10 second units and displayed on the screen. That is, after generating and thumbnail images by extracting and decoding I frames of the video existing at 10 second intervals from the first video file, the generated thumbnail images are displayed on one screen.

In this case, when the user selects a predetermined thumbnail image displayed on the screen, the video is played from the corresponding video portion.

According to the present invention, after the user selects a desired video file through the preview function, the user can play the desired video portion without any manipulation.

4 is a block diagram illustrating a thumbnail image display device of the present invention.

As shown in the drawing, the thumbnail image display apparatus of the present invention includes an input unit 210, a memory 220, a thumbnail image processor 230, a display unit 240, and a controller 250.

The input unit 210 is a device for receiving a command related to a preview function from a user, for example, a thumbnail image display command for displaying summary information of an image file stored in the memory 220 as a thumbnail image and a plurality of displayed on the screen. Commands such as a thumbnail image selection command for selecting a predetermined thumbnail image among the four thumbnail images are received.

The input unit 210 may use a keyboard and a mouse when the digital device is a personal computer, a remote controller may be used when the digital television receiver is used, and a keypad may be used when a mobile communication terminal or a digital camera is used.

The memory 220 is a device for storing image data such as a still image or a moving image, and the memory 220 includes a flash memory, a RAM, a ROM, an HDD, and the like.

The memory 220 includes a thumbnail buffer 225 for storing a thumbnail image generated by extracting and decoding an I frame from the still image or video data.

The thumbnail image processing unit 230 extracts an I frame from a still image or video data stored in a memory, an I frame extracting module 231, and a thumbnail image generating module 234 that decodes the extracted I frame to generate a thumbnail image. It is configured to include.

The I frame extraction module 231 analyzes the header information of each video data to determine the number of I frames and the position information of the I frames, and then extracts the I frames using them.

In this case, the I frame extraction module 231 extracts the first I frame of each video data, and then extracts I frames located at predetermined time intervals.

The thumbnail image generation module 234 decodes the I frame extracted by the I frame extraction module 231 and then scales it to generate a thumbnail image.

The display unit 240 displays the generated thumbnail image on the screen under the control of the controller 250.

The controller 250 controls the thumbnail image processor 230 to generate a thumbnail image by extracting and decoding I frames of still image and video data stored in the memory 220.

The controller 250 stores the thumbnail image generated by the thumbnail image processor 230 in a thumbnail buffer 225 and also displays the generated thumbnail image on the screen through the display 240.

In this case, the controller 250 simultaneously displays thumbnail images of the corresponding video data for each region in one screen, and the plurality of thumbnail images for each video data in each region is displayed on the screen continuously by changing according to a preset time unit. And a thumbnail image display module 255.

5 is a flowchart illustrating a method of displaying a thumbnail image of the present invention.

As shown in the drawing, first, the controller 250 checks whether a thumbnail image display command is input from the input unit 210 (S100), and when a thumbnail image display command is input, the thumbnail image is currently set to be displayed on one screen. After checking the number of, a still image and a video are selected according to the number of thumbnail images set to be displayed on one screen (S 110).

For example, if the number of thumbnail images currently set to be displayed on one screen is four, the controller 250 selects the fourth image data among the still image and video data stored in the memory 220 in order, and then displays the thumbnail image. To be displayed.

Next, the thumbnail image processor 230 extracts and decodes the I frame from the selected still image and video data to generate a thumbnail image, and the controller 250 stores the generated thumbnail image in the thumbnail buffer 225. (S 120).

In this case, when the selected image is a video, the thumbnail image processor 230 extracts I frames located at a first predetermined time interval starting from the first I frame of each video data, and decodes the extracted I frames. Create an image.

That is, the thumbnail image processing unit 230 generates a plurality of thumbnail images at predetermined first time intervals for each of the selected videos.

Subsequently, the controller 250 displays the plurality of thumbnail images for each video in each area within a screen, and the plurality of thumbnail images for each video is continuously displayed at a predetermined first time interval in each area. (S 130).

That is, as shown in FIG. 2, the thumbnail image is displayed on the screen in a predetermined first time unit for each region in one screen.

In this case, since the thumbnail image of the video is changed according to the first preset time interval, the user can easily distinguish between the picture and the video, and can easily select the desired video.

In consideration of the purpose of the preview function of providing summary information of the image data, it is preferable that the first time interval for displaying the thumbnail image is set to 1 to 2 seconds.

Subsequently, the controller 250 checks whether a thumbnail image selection command for selecting a predetermined thumbnail image among the thumbnail images displayed on the screen is input through the input unit 210 (S 140).

As a result of the checking of step S 140, when a thumbnail image selection command is input, the controller 250 controls the thumbnail image processor 230 to select an I frame positioned at a second preset time interval from the video data selected by the user. After extracting and decoding to generate a plurality of thumbnail images, they are stored in the thumbnail buffer 225 (S 150).

In this case, the thumbnail image processor 230 generates thumbnail images as many as the number of thumbnail images set to be displayed on one screen.

Next, the controller 250 displays a plurality of thumbnail images according to the second time interval through the thumbnail image display module 255 in one screen (S 160).

That is, as shown in FIG. 3, four thumbnail images of the selected moving picture data are displayed on the screen by dividing them by second time intervals according to the moving picture playback time in one screen.

Herein, the second time interval may be arbitrarily set according to the playing time of the video. For example, the second time interval may be set from several seconds to several minutes for a video having a short playing time, and may be set from several minutes to several tens of minutes for a video having a long playing time. Can be.

In this case, when the user selects a predetermined thumbnail image displayed on the screen, playback starts from the corresponding video portion, so that the user can play back the desired video portion without any manipulation.

In the present invention, when the user requests the preview function, since thumbnail images are continuously displayed at each first time interval according to each video, a large amount of computation must be processed in the process of extracting and decoding an I frame.

For example, if it is set to display nine thumbnail images on one screen, it is necessary to analyze the headers of the nine video data to find and extract the position of the I frame, and then decode them. Can be.

In general, a process of decoding an I frame includes 1) a variable length decoding process for converting compressed image data into discrete cosine transform (DCT) coefficients, and 2) inverse quantizing the DCT coefficients. Process, 3) an inverse discrete cosine transform (IDCT) process of the inverse quantized DCT coefficients, and 4) a loop filtering process to remove noise. To create a thumbnail image.

However, in the present invention, as shown in FIG. 6, only the variable length decoding process, the inverse quantization process, and the DCT inverse transform process having a great influence on the image quality are performed, and the loop filtering process is omitted.

In the case of a thumbnail image, the loop filtering process may be omitted because the purpose of providing a summary information of the corresponding video is to be provided.

In this case, in performing the DCT inverse transformation process, the present invention fixes the values of the high frequency region to 0 and reduces the amount of DCT computation by using only the values of the low frequency region.

For example, as shown in FIG. 7, by performing a DCT operation using only 5 × 5 data in 8 × 8 block units, a DCT operation can be quickly performed without large loss of image quality.

In addition, in the present invention, when the extracted I frame is stored in a memory for decoding, the data capacity is reduced and stored in a range where there is no significant loss in image quality, and then decoding is performed. This reduces the time for storing I frames in memory for decoding and also reduces the power consumed in this process.

Although the present invention has been described in detail with reference to exemplary embodiments above, those skilled in the art to which the present invention pertains can make various modifications to the above-described embodiments without departing from the scope of the present invention. I will understand.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

1 is a view showing a screen configuration displaying a conventional thumbnail image.

2 is a diagram illustrating one embodiment of a thumbnail image screen of the present invention;

3 shows another embodiment of a thumbnail image screen of the present invention.

4 is a block diagram showing a thumbnail image display device of the present invention;

5 is a flowchart illustrating a method of displaying a thumbnail image of the present invention.

6 is a flowchart illustrating a process of decoding an I frame of the present invention.

7 is a view showing a state using only the value of the low frequency region of the inverse quantized DCT coefficients in the DCT inverse transformation process of the present invention.

Explanation of symbols on the main parts of the drawings

210: input unit 220: memory

225: thumbnail buffer 230: thumbnail image processing unit

231: I frame extraction module 234: thumbnail image generation module

240 display unit 250 control unit

255: thumbnail image display module

Claims (10)

A memory for storing image data; A thumbnail image processor which generates a thumbnail image of the image data stored in the memory, and generates a plurality of thumbnail images at preset time intervals for each of the image data; A display unit configured to display the generated thumbnail image on a screen; And And a controller configured to display the generated thumbnail image on a predetermined area of the screen for each image data, and to display a plurality of thumbnail images for each image data in each area continuously at predetermined time intervals. Display device. The method of claim 1, And the memory comprises a thumbnail buffer for storing thumbnail images generated by the thumbnail image processing unit. The method of claim 1, The thumbnail image processing unit, An I frame extraction module for extracting I frames located at predetermined time intervals for each of the image data stored in the memory; And And a thumbnail image generation module for decoding the extracted I frame and scaling to generate a thumbnail image of the corresponding image data. Selecting image data from a memory according to the number of thumbnail images set to be displayed on a screen when a thumbnail image display command is input; Generating a thumbnail image of the selected image data, and generating a plurality of thumbnail images at predetermined first time intervals for each image data; And Displaying the generated thumbnail image on a predetermined area of the screen for each image data, and displaying a plurality of thumbnail images for each image data in each area in succession at the first time interval. Display method. The method of claim 4, wherein Generating the thumbnail image, Extracting I frames located at the first time interval from the selected image data; And And decoding the extracted I frames and scaling to generate a plurality of thumbnail images. The method according to claim 4 or 5, After displaying the created thumbnail image on the screen, Generating a thumbnail image of an I frame located at a second preset time interval from the corresponding image data when a thumbnail image selection command for selecting a predetermined thumbnail image from among the thumbnail images displayed on the screen is input; And And displaying the thumbnail images according to the second time intervals in predetermined areas of the screen, respectively. The method of claim 5, Decoding the extracted I frames, Converting the image data into a discrete cosine transform (DCT) coefficient; Inverse Quantized the DCT coefficients; And And performing an inverse discrete cosine transform (IDCT) on the inverse quantized DCT coefficients. The method of claim 7, wherein Converting the inverse discrete cosine, And using only a value of a low frequency region among the inverse quantized DCT coefficients. Generating a thumbnail image of an I frame located at predetermined time intervals from the corresponding image data when a thumbnail image selection command for selecting a predetermined thumbnail image from among the thumbnail images displayed on the screen is input; And And displaying the thumbnail images according to the time intervals in predetermined areas of the screen, respectively. The method of claim 9, Generating the thumbnail image, Extracting I frames located at predetermined time intervals from the image data; And And decoding the extracted I frames and scaling to generate a plurality of thumbnail images.

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