JPH11284839A - Image reproduction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the image reproduction method that quickly displays a thumb nail image. SOLUTION: In a 1st expansion processing (step S2) where compressed data of pluralities of images are expanded up to a stage on the way, intermediate expanded data as to pluralities of image is generated, in a size conversion processing (step S4), a size of intermediate expanded data of pluralities of the images generated by the 1st expansion processing is converted, intermediate expanded data as to pluralities of images are outputted after size conversion processing (step S5), in a 2nd expansion processing (step S3) where the intermediate expansion data as to pluralities of images generated by the 1st expansion processing are expanded up to a final stage from the midway stage as above to generate expansion data as to pluralities of images and expansion data as to one image are outputted from the generated expansion data as to pluralities of the images (step S7).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reproducing method, and more particularly, to an image reproducing method capable of rapidly displaying thumbnail images.

[0002]

2. Description of the Related Art Conventionally, in an image recording / reproducing apparatus for recording / reproducing data of a still image, an image to be a subject is digitized at the time of recording, and the digitized image is compressed by a predetermined compression method. There is known a method in which image data is generated by compression and the generated image data is recorded on a predetermined recording medium by a predetermined number.

In such a conventional image recording / reproducing apparatus, when reproducing a recorded still image and displaying it on a monitor screen, it is necessary to reproduce the image data in order to facilitate searching and editing. Earlier, a plurality of reduced sample images called thumbnails were displayed on the monitor screen. Here, it is desirable that the time until the thumbnail image is displayed, that is, the waiting time until the thumbnail is displayed, is as short as possible.

[0004]

However, when a thumbnail image of compressed image data is displayed, conventionally, a complete decompression process is performed so that a full-size display image is displayed, and then the thumbnail image is displayed. Has been performed to reduce the image size so that the image is displayed. For this reason, image display of thumbnails by the conventional image reproduction method requires a time obtained by adding the time required for decompression to the full size and the time required for processing for reducing the size, and the waiting time until the display is felt long. There was a problem.

[0005] When displaying thumbnail images with the same number of colors as in the case of displaying full-size images, the display of thumbnails is often excessive. It was taking a long time.

[0006] The present invention has been proposed in view of the above problems, and has as its object to provide an image reproducing method capable of quickly displaying thumbnail images.

[0007]

In order to solve the above-mentioned problems, an image reproducing method according to the present invention performs a first decompression process for decompressing compressed data of a plurality of images to an intermediate stage. It generates intermediate decompressed data for the image, performs size conversion processing for converting the size of the image on the intermediate decompressed data for the plurality of images generated by the first decompression processing, and processes the plurality of images after the size conversion processing. The second decompression process of outputting intermediate decompressed data of the images and decompressing the intermediate decompressed data of the plurality of images generated by the first decompression process from the middle stage to the final stage allows the plurality of images to be obtained. Is generated, and decompressed data for one image is output from the generated decompressed data for a plurality of images.

In the image reproducing method, the size of the image is converted with respect to the intermediate decompressed data of the plurality of images generated by the first decompression process of decompressing the compressed data of the plurality of images to an intermediate stage. A size conversion process is performed, and intermediate decompressed data for a plurality of images after the size conversion process is output.

[0009] By performing the second decompression processing while outputting the intermediate decompression data for a plurality of images after the size conversion processing, the waiting time when outputting the decompression data is reduced.

[0010]

Embodiments of the present invention will be described in detail with reference to the drawings. First, the image reproducing method of the present invention will be described with reference to the flowchart shown in FIG.

In step S1, a file in which image data of a still image to be displayed is stored in the form of compressed data (hereinafter referred to as a compressed image data file) is accessed. For example, in step S1, a compressed image data file in which a plurality of pieces of compressed data (hereinafter, referred to as compressed image data) about images from a predetermined recording medium such as a hard disk, an optical disk, or a flash memory is stored is used as a work area. Processing for storing the data in a memory such as a RAM (hereinafter, referred to as a decompression memory) is performed.

In this example, it is assumed that the compressed image data file stores compressed image data of RGB 16 bits (2 ¹⁶ = 65536).

In the present invention, the number of images displayed as thumbnails is not particularly limited, but in this example, for convenience of explanation, the number of images displayed as thumbnails is assumed to be four.

In the next step S2, a decompression process for a plurality of compressed image data is started. Then, at a stage where the decompression process is not completely completed, the decompression process is temporarily stopped. Hereinafter, this processing in step S2 is referred to as first-stage expansion processing. As a result, intermediate decompressed data of a plurality of images, which is data at a stage before complete decompression is performed, is sequentially generated.

The stage at which the first-stage decompression process is stopped in step S2 is not particularly limited, but a trade-off between image definition and processing time is taken into consideration. And step S described later.
In displaying the thumbnail image in step 5, it is sufficient that the thumbnail image can be understood.

The number of pieces of image data to be processed in the first-stage decompression processing in step S2 is not particularly limited. For example, the number of pieces of image data to be displayed as thumbnails (in this example, After processing is performed on the image data (for four sheets), the process proceeds to the next step (steps S3 and S4). Further, after the first-stage decompression process for the image data for the number of thumbnails to be displayed is completed, the first-stage decompression process for the remaining image data is performed. In order to speed up the processing, the first-stage expansion processing for the remaining image data may be performed in parallel with the processing in step S3 and step S4 described below.

When the intermediate decompressed data is generated in step S2, as shown in FIG.
And the processing of steps S4 to S6 are performed in parallel.

In step S3, the second-stage decompression process is performed on the target compressed image data file by continuing to decompress the intermediate decompressed data. The second-stage decompression process is performed from the stage temporarily stopped in the first-stage decompression process in step S2 until the data decompression is completely completed.

In step S3, first, the second-stage expansion process is performed on the intermediate expansion data for the number of thumbnails to be displayed (in this example, four). This allows
Fourteen pieces of 16-bit expanded data of the number of colors (hereinafter referred to as 16-bit expanded data) are generated. When this process is completed, the process waits until the process of step S6 described later is completed, and proceeds to step S7 when the process of step S6 is completed. Note that the second-stage expansion process may be performed on the fifth and subsequent intermediate expansion data while waiting for the end of the process in step S6.

On the other hand, in step S4, an image size conversion process for converting the image size of the intermediate decompressed data is performed, and a color number conversion process for converting the number of colors of the intermediate decompressed data is performed. Specifically, in the image size conversion process, a process of reducing the image size of the intermediate decompressed data for thumbnails is performed. Further, in the number-of-colors conversion process, a process of reducing the number of colors of the intermediate decompressed data is performed.

Here, as for the method of reducing the image size of the intermediate decompressed data, an optimal method may be used for each compression / decompression algorithm to be used. On the other hand, regarding the conversion of the number of colors for the intermediate decompressed data, for example, as shown in FIG.
Look Up Table, hereafter called CLUT. ) Using n
The bit color number data is converted into m bit color number data. In this example, the above-described 16-bit color number is converted into an ⁸ -bit (2 ⁸ = 256) color number. As a result, in step S4, four pieces of thumbnail display data having the number of colors of 8 bits are generated.

Then, in the next step S5, the data of four thumbnails among the generated thumbnail display data is displayed on the LCD.
(Liquid Crystal Display). Thus, as shown in FIG. 3A, four thumbnail images (Picture 1 to Picture 4) are displayed on the monitor screen 10 of the image display device in 8-bit color numbers.

Further, in the next step S6, a thumbnail of an image desired to be displayed in full size is selected from the four thumbnail images displayed on the monitor screen 10. Here, it is assumed that Picture1 is selected from the four thumbnails shown in FIG.

In step S7 when both the processing in step S3 and the processing in step S6 are completed, the 16-bit expanded data corresponding to the selected thumbnail (in this case, Picture 1) is output to the image display device.
As a result, as shown in FIG. 3B, the picture of Picture 1 is displayed on the monitor screen 10 in full size and with 16 bits of color.

As described above, according to the image reproducing method of the present invention,
Decompress the compressed image data to full size in two stages,
Since thumbnails are displayed at the first stage expansion,
The time until the display of the thumbnail is significantly reduced.

Further, according to the image reproducing method of the present invention, during the thumbnail display in step S5, the image is expanded to the full size by another task, that is, in step S3.
By performing the second-stage decompression processing in parallel with the processing in steps S4 and S5, the time required for shifting from step S6 to step S7 is reduced. That is, since it is possible to instantaneously shift from the thumbnail display state shown in FIG. 3A to the full size display state shown in FIG. 3B, a full-size image is displayed after selecting a specific thumbnail image. Waiting time is almost eliminated.

Further, in the image reproducing method of the present invention, in step S4, a color number conversion process for converting the number of colors of the intermediate decompressed data is performed. Excessive display can be avoided.

The thumbnail display image data (intermediate decompressed data) generated by the image reproducing method of the present invention is rougher than the thumbnail display image data generated by the conventional image reproducing method. However, even if the intermediate decompressed data is rough image data, the size is reduced when displaying thumbnails,
The roughness becomes less noticeable.

FIG. 4 shows an outline of a data decompression device used for realizing the image reproducing method of the present invention as a block for each functional module. In addition,
Each of these blocks shown in FIG. 4 can be realized using either hardware or software. As shown in FIG. 4, the data decompression device 1 includes a decompression memory 2, an engine unit 6 including a decompression engine 3, a size conversion engine 4, and a color number conversion engine 5, a setting unit 7, and a CLUT 8. I have.

The expansion memory 2 is a module serving as a work area for performing the above-described processing such as expansion, size conversion, and color number conversion.

The setting unit 7 is a module for setting the display size and the number of colors of the thumbnails and the number of colors of the final image displayed in full size, and is constituted by a file or a register. Here, the display size of the thumbnail is set by setting the value of the intermediate size shown in FIG. The number of colors of the thumbnail can be set to an arbitrary value by setting the value of the number of intermediate colors. In this example, it is assumed that the value of the number of intermediate colors is set to 8 bits.

Further, the number of colors of the final image is set by setting the value of the number of final colors. In the data decompression device 1, two colors can be set for the final image displayed in full size. In this example, it is assumed that the value of the final color number is set for two types of 24 bits (2 ²⁴ = 16777216) and 16 bits.

The engine unit 6 refers to the setting unit 7 to perform a decompression process on the data stored in the decompression memory 2,
This module performs size conversion processing and color number conversion processing. In the engine unit 6, the extension engine 3 performs the first-stage extension process in step S2 and the second-stage extension process in step S5. The size conversion engine 4 of the engine unit 6 performs the image size conversion processing on the intermediate decompressed data in step S3 according to the set value of the intermediate size in the setting unit 7. Further, the color number conversion engine 5 of the engine unit 6 performs the color number conversion process on the intermediate decompressed data in step S4 according to the set value of the intermediate color number in the setting unit 7.

When two types of colors are set for the final image to be displayed in full size, in step S6, a thumbnail to be displayed in full size and a color number in full size display are selected. Thereby, the color number conversion engine 5
According to the setting value of the final number of colors in the setting unit 7,
The conversion process of the number of colors for the expanded data is performed using the UT 8.

Hereinafter, the image reproduction processing of the present invention performed by using the data decompression device 1 will be described with reference to the flow chart of FIG.

In step S 1, the data decompression device 1 accesses the compressed image data file from the above-mentioned predetermined recording medium, and sequentially stores a plurality of compressed image data in the decompression memory 2. In this example,
It is assumed that the compressed image data file stores compressed image data of 24 bits.

Next, the decompression engine 3 sequentially performs the first-stage decompression processing in step S2 described above on the compressed image data. That is, the decompression engine 3 starts decompression processing for a plurality of pieces of compressed image data, and temporarily stops the decompression processing when this decompression processing is not completely completed. As a result, the intermediate decompressed data of the image, which is the data at the stage before the decompression process is completely completed, is generated for four thumbnail images.

When the intermediate expansion data is generated by the expansion engine 3, the intermediate expansion data is copied, and the copied intermediate expansion data is supplied to the size conversion engine 4. The size conversion engine 4 performs an image size conversion process on the intermediate decompressed data based on the set value of the intermediate size of the setting unit 7 (Step S4). Thereby, the image size of the intermediate decompressed data is reduced for thumbnail display. The intermediate decompressed data after the image size conversion processing is supplied to the color number conversion engine 5.

Further, in the data decompression device 1, the color number conversion engine 5 performs a color number conversion process (step S4) on the intermediate decompressed data. This color number conversion processing is performed based on the set value of the number of intermediate colors in the setting unit 7 based on the CLUT 8
This is performed using Thereby, in the data decompression device 1, 8-bit thumbnail display data is generated. The thumbnail display data is output on the monitor screen 10 of the above-described image display device, so that the thumbnail display data shown in FIG.
As shown in (A), four thumbnail images (Picture 1 to Picture 4) are displayed on the monitor screen 10 in 8-bit color numbers (step S5).

On the other hand, while the thumbnail display data is generated, the decompression engine 3 performs the second-stage decompression processing on the intermediate decompressed data (step S3). Thus, 24-bit decompressed data is generated.

Then, in step S 6, when the selection of the thumbnail to be displayed in full size and the number of colors for full size display are selected, the color number conversion engine 5 sets the CLUT 8 based on the setting value of the final color number in the setting unit 7. Is used to convert the number of colors for the 24-bit decompressed data. As a result, in step S6, for example, if Picture1 is selected as a thumbnail to be displayed in full size, and the number of colors in full size display is 16 bits, as shown in FIG. The image is displayed in full size and with 16 bits of color.

As described above, according to the data decompression device 1 to which the data reproducing method of the present invention is applied, the intermediate decompressed data is used for the thumbnail display. As compared with the conventional image reproducing method for creating the above data, the time until the thumbnail is displayed is shortened, and the waiting time on the user's bodily sensation is shortened. In particular, the data decompression device 1 is connected to a MIPS (Million Inst
In the case of a built-in CPU having a low value of (ructions per second), the power of this CPU can be apparently supplemented.

Further, according to the data decompression device 1, the number of colors of the display image for the thumbnail can be set arbitrarily, so that the display is performed according to the number of colors of the monitor screen 10 to be displayed regardless of the number of colors of the original image. Data can be output. For example, 24 bits on the 8-bit CLUT display mode screen
It can be used when displaying the original image of the bit RGB with an icon or the like.

FIG. 5 shows a comparison of the time required for thumbnail display between the conventional image reproducing method and the image reproducing method of the present invention. As is apparent from FIG. 5, according to the image reproducing method of the present invention, the conventional full-size decompression processing is divided into a first-stage decompression process and a second-stage decompression process. Since the thumbnails are displayed after the decompression process and before the second-stage decompression process, the time until the thumbnails are displayed is greatly reduced.

[0045]

As described above in detail, according to the image reproducing method according to the present invention, a plurality of images generated by the first decompression process for decompressing compressed data of a plurality of images to an intermediate stage. The size of the intermediate decompressed data of the image is subjected to a size conversion process to convert the size of the image, and the intermediate decompressed data of a plurality of images after the size conversion process is output, so that the thumbnail images can be displayed quickly. It is possible to do.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining an image reproducing method according to the present invention.

FIG. 2 is a diagram for explaining a process of changing the number of colors of expanded intermediate data.

FIG. 3 is a diagram for explaining a state in which a plurality of thumbnails or one image is displayed on a monitor screen.

FIG. 4 is a block diagram showing a configuration example of a data decompression device used for realizing the image reproducing method of the present invention.

FIG. 5 is a diagram showing a comparison between the time required for thumbnail display in the conventional image reproducing method and the time required for thumbnail display in the image reproducing method of the present invention.

[Explanation of symbols]

1 data decompression device, 2 decompression memory, 3 decompression engine, 4 size conversion engine, 5 color conversion engine, 7 setting unit, 8 CLUT

Claims (8)

[Claims] 1. A first decompression process for decompressing compressed data of a plurality of images to an intermediate stage, generating intermediate decompressed data of the plurality of images, and generating the intermediate decompressed data of the plurality of images by the first decompression process. Applying a size conversion process for converting the size of the image to the intermediate decompressed data for the plurality of images, outputting intermediate decompressed data for the plurality of images after the size conversion process, A second decompression process for decompressing the intermediate decompressed data for the plurality of images generated by the processing from the middle stage to the final stage, generating decompressed data for the plurality of images; 1 from the decompression data for one image
An image reproducing method, comprising outputting decompressed data for one image. 2. The method according to claim 1, further comprising: outputting intermediate decompressed data of the plurality of images after the size conversion processing.
2. The image reproducing method according to claim 1, wherein the image is expanded. 3. An intermediate decompressed data of the plurality of images generated by the first decompression process,
2. The image reproduction method according to claim 1, wherein thumbnail data is generated by performing a size conversion process for reducing the size of the image, and thumbnail data for the plurality of generated images is output. 4. An intermediate decompressed data of the plurality of images generated by the first decompression process,
4. The image reproducing method according to claim 3, wherein a color number conversion process for converting the number of colors of the image is performed. 5. An intermediate decompressed data of the plurality of images generated by the first decompression processing,
4. The image reproducing method according to claim 3, wherein a color number conversion process for reducing the number of colors of the image is performed. 6. Outputting the generated thumbnail data of the plurality of images to an image display means, and selecting one thumbnail image to be displayed in full size from the plurality of thumbnail images displayed on the image display means. 4. The apparatus according to claim 3, further comprising: outputting, to the image display means, decompressed data for one image corresponding to the one thumbnail image selected from the generated decompressed data for the plurality of images. Image playback method. 7. An intermediate decompressed data of the plurality of images generated by the first decompression processing,
2. The image reproducing method according to claim 1, wherein a size conversion process for specifying an image size and converting the image size into the specified size is performed. 8. The method according to claim 1, wherein the generated decompressed data for a plurality of images is subjected to a color number conversion process for converting the number of colors of the image, and then output. Item 7. The image reproducing method according to Item 1.