JP2003099020A - Display system for compressed still image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display system for a compressed still image which can continuously display a meaningful image without such a phenomenon that a current picture being displayed is disordered even when a next picture is decompressed during the display of the current picture in the case that JPEG files in different MCU formats are stored on a recording medium. SOLUTION: This system is equipped with a compressing and expanding chip 2 which reads compressed image data out of the recording medium, expands them and displays the expanded data, a memory card 4, a camera 5a, and a distributed news receiving means 5b which output data to be displayed on a display device 1, and a control means 3a and a switching means 3b which read in the output signals from those devices and switch the data to be inputted to the display device 1. The compressing and expanding chip 2 outputs the compression formats of compressed still picture files of one picture inputted to itself by the files to the control means 3a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of displaying compressed still image data or the same file, and more particularly to a JPEG (Joint) which is a standard or one of standards for compression / decompression of still images. Photograph
The present invention relates to a configuration suitable for decompressing or decompressing a still image compressed by h Expert Group) and displaying it, and relates to a display method of a compressed still image.

[0002]

2. Description of the Related Art RGB is the most popular color expression method.
In addition to the formats, there are various formats. For example, in the JPEG standard, a method of expressing a color by luminance (Y) and color difference (Cb, Cr), which is also called YUV format or YCbCr format, is used. On the other hand, as is well known, in the JPEG standard, there is a format called MCU (Minimum Coded Unit) as a minimum unit of compression / expansion (method of dividing a screen). Y: Cb: Cr = 4: 1: 1, Y: C
b: Cr = 4: 2: 2 and Y: Cb: Cr = 4:
4: 4 is an example of a practical form of MCU. Y:
Cb: Cr = 4: 1: 1 means that the luminance component (Y) 4
This means an MCU composed of one unit, one color difference component (Cb), and one color difference component (Cr). JPEG (hereinafter JPE
In the compression of G standard (also referred to as simply JPEG), after each MCU is color separated into Y, Cb, and Cr,
While being divided into 8 × 8 blocks, conventionally well-known processes disclosed as standard such as DCT transform, quantization, and entropy compression are performed in this block unit.

Still image data compressed by, for example, JPEG is recorded or stored in a recording medium such as a memory card, the still image data is sequentially read from the recording medium, and a compression / expansion chip (IC) compatible with JPEG is used. It is a conventional practice to decompress or decompress and display on a display device of a display system. For the purpose of decompressing and displaying compressed still image data, for example, in a display device of a vending machine or a display device in an elevator car,
There are some that display various information and advertisements / promotions. Note that, hereinafter, still image data compressed by JPEG for one sheet (one screen) will also be referred to as a JPEG file.

From the above description, the JPEG file is
Even though it is the same JPEG file, the MCU format is
Y: Cb: Cr = 4: 1: 1, Y: Cb: Cr = 4:
It can be seen that there are different ones such as 2: 2 and Y: Cb: Cr = 4: 4: 4. In a display system, these different Ms may be stored on one or more recording media.
If JPEG files in the CU format are mixed, the JPEG files are continuously read from the one or more recording media, decompressed, and continuously displayed one after another at predetermined time intervals. The phenomenon that the screen is disturbed during the display occurs. In reading, decompressing, and displaying a JPEG file, when a certain screen is displayed, the next screen is decompressed at the same time. If the MCU formats of the current display screen and the next display screen are different, the next screen It is considered that this is because the decompression operation adversely affects the display operation of the current screen. Therefore, the JPEG file recorded on one or more recording media of a certain display system is
It is common to unify them into one MCU format. However, this may not be possible depending on the application. For example, in an elevator car display system,
This is a case where the administrator of the system receives each JPEG file from each advertiser and stores the JPEG file in a recording medium. Each advertiser will pass the J
A PEG file (a record carrier in which the PEG file is stored) is created. At this time, which MCU format is used depends on the judgment and circumstances of the advertiser or the trader. The manager of the system can specify the MCU format. However, because the advertiser does not have a digital camera of the MCU format, the format of all the files stored in the recording medium of the display system is not completely unified, and the advertiser does not have the same format. Nor is it possible to force the format of the MCU. Therefore, for various reasons, it is still necessary to mix JPEG files of different MCU formats in one or a plurality of recording media included in the display system.

In a certain display system, Y: Cb: Cr = 4: 1: 1, Y:
Cb: Cr = 4: 2: 2 and Y: Cb: Cr = 4:
It is assumed that 4: 4 JPEG files are mixed. Then, it has been confirmed that the following phenomenon occurs when the image is decompressed (decompressed) and displayed by a compression / decompression chip (IC) compatible with JPEG. Y: Cb: Cr = 4: 1:
While displaying the 1 JPEG file, Y: Cb: Cr =
JP of 4: 2: 2 or Y: Cb: Cr = 4: 4: 4
When the EG file is decompressed, the screen of the file being displayed is disturbed. While displaying a JPEG file of Y: Cb: Cr = 4: 2: 2, JPEG of Y: Cb: Cr = 4: 1: 1
When you unzip a file, the screen of the displayed file is distorted. When decompressing a JPEG file with Y: Cb: Cr = 4: 4: 4, a JP with Y: Cb: Cr = 4: 2: 2 being displayed is displayed.
The screen of the EG file is not disturbed. Y: Cb: Cr = 4:
While displaying a 4: 4 JPEG file, Y: Cb: Cr
When the JPEG file of = 4: 1: 1 is decompressed, the screen of the file being displayed is disturbed. Y: Cb: Cr = 4: 2:
When decompressing the JPEG file of No. 2, Y: Cb:
The screen of the JPEG file of Cr = 4: 4: 4 is not disturbed. That is, when the screen to be displayed next is decompressed while the current screen is being displayed, the current screen is disturbed because Y: Cb: Cr
= 4: 1: 1 (= form A) and Y: Cb: Cr =
4: 2: 2 = Y: Cb: Cr = 4: 4: 4 (= form B). In this way, JP from the recording medium
Read the EG file continuously, decompress (decompress),
The conventionally known method of continuously displaying has a problem that when the JPEG file has a mixture of MCU formats A and B, the phenomenon that the screen is disturbed inevitably occurs. If the conventional continuous display method of JPEG files is used to avoid screen disturbance, the next time an MCU of a format different from the current screen is decompressed, the display on the display device is stopped during the decompression. , When the decompression is finished, the screen will be displayed. That is, there is a blank time in which a meaningful image is not displayed on the screen of the display device of the display system.

[0006]

The compressed still image display system according to the present invention has been made in view of the problems of the above-described conventional technique, and an object thereof is to solve the following problems. If the next screen (data) is decompressed or expanded while the current screen (data) is being displayed, the current screen being displayed may be disturbed. For example, image data files of different JPEG MCU formats, such as format A and format B Provided is a compressed still image display method capable of continuously displaying meaningful images without causing screen disturbance even when a JPEG file is stored in a recording medium.

[0007]

A method of displaying a compressed still image according to the present invention is a solution to the above-mentioned problems.
It looks like this: The compressed still image display system according to claim 1 has the following configuration. In an image display system having a display device and at least one or more recording media, decompressing means for executing reading of compressed still image data from the recording media, decompression, and display after decompression.
The display device includes a data generation unit that outputs data to be displayed on the display device, and a control unit that reads the output signal of the data generation unit and switches the data input to the display device. Further, the decompressing unit is configured to output a compression format of the compressed still image file for one screen input to itself, and the control unit reads the compression format and switches the data. Is controlled.

A compressed still image display system according to a second aspect is the compressed still image display system according to the first aspect.
The compression of the compressed still image and the expansion by the expansion means are based on the JPEG standard. That is, the decompression means is a functional block (a component of the image display system) capable of decompressing and displaying the JPEG file.

[0009]

1 is a block diagram of a compressed still image display system according to the present invention. This compressed still image display system will be described as being applied to display in an elevator car (this applied product is simply referred to as a system). The display device 1 is provided at a predetermined portion in an elevator car (not shown), and is, for example, a CRT, LCD, P
An electric display device such as DP or ELD is used. Also,
The display device 1 incorporates a display device drive means (not shown). Of course, the drive means may be so-called externally attached. This system, as a recording medium,
The memory card 4 is used. A memory card is, for example, a flash memory device known under the trade name of SmartMedia or CompactFlash (registered trademark). The memory card 4 is a storage element for storing at least a compressed still image, and at least one is provided in the system. That is, the compressed still image data is always stored in at least one of the memory cards 4 included in the system. However, this does not mean that data other than compressed still images should not be stored in the memory card 4. In addition,
A magnetic recording device such as a hard disk device, an optical recording device, or a semiconductor memory (board) may be used as the recording medium that is an essential component of the present invention. Here, the compressed still image data recorded (stored) in the memory card 4 is a JPEG file, and at least one file whose MCU format is Y: Cb: Cr = 4: 1: 1 The above is stored and the MCU format is Y: Cb: Cr = 4: 2: 2 or Y: Cb:
It is assumed that either one or both of the Cr = 4: 4: 4 files are stored. As described above, the compression format of a JPEG file in which the MCU format is Y: Cb: Cr = 4: 1: 1 is called compression format A, and the MCU format is Y: Cb: Cr = 4: 2: 2. And the same Y: Cb: Cr =
A compression format of a 4: 4: 4 JPEG file will be referred to as a compression format B.

The system always has a decompression means for displaying the JPEG file read from the memory card 4 on the display device 1. Here, the compression / expansion chip 2 corresponds to this. The compression / decompression chip 2 performs compression to a JPEG file, writing to a recording medium, reading from a recording medium, decompression of a JPEG file, output of decompressed image data to the display device 1, and display control of the display device 1. Do L
SI, which can be commercially available. The compression / expansion chip 2 is JP
The EG file (compressed still image data) is read and expanded. The decompressed image data is sent to the display device 1,
Under the display control of the compression / expansion chip 2, a screen corresponding to the JPEG file is displayed on the display device 1.

The compression / expansion chip 2 expands while displaying the current screen (expanded JPEG file) on the display device 1 and reading the screen (next JPEG file) to be displayed next from the memory card 4. . That is, the compression / expansion chip 2 displays the current screen on the display device 1 at the same time as the next screen (next JPEG File) is decompressed. .
It is now assumed that the current screen decompresses and displays a JPEG file of format A. Then, assume that the screen to be displayed next is a JPEG file of format B. Then, the decompression work of the format B JPEG file by the compression / decompression chip 2 adversely affects the display control of the current screen by the compression / decompression chip 2, and the image displayed on the display device 1 is disturbed.

In the present invention, this image distortion is eliminated as follows. In addition to the JPEG file, data generating means for outputting the data to be displayed on the display device 1 is provided. The memory card 4, the camera 5a, the delivery news receiving means 5b and the RAM 7 correspond to the data generating means.
Non-compressed data is stored in a predetermined area of the memory card 4. Of course, this uncompressed data may be stored in a memory card (not shown) different from the memory card 4 prepared. That is a matter of design choice for those skilled in the art. The non-compressed data is, for example, text data, and the content thereof may be a message or guidance to passengers in the elevator. For example, “Welcome! To XX building.”, “Sunday, September 30, business hours from 10:00 AM to 20:00 PM” and the like. Of course, the uncompressed data may be (simple, small capacity) image data. For example, monochrome image data having a small amount of information may be used. The camera 5a is, for example, a camera for monitoring the inside of the elevator car or the elevator hall, and captures a normal moving image or a still image. The video signal output from the camera 5a is uncompressed image data. The distributed news receiving unit 5b is, for example, a pager (registered trademark), a PHS machine, a mobile phone, a wireless receiver, or the like, and is a device that receives information by a distributed news service provided by Kyodo News, for example. Many paid and free news services offered by vendors can be paged. Therefore, if a pager is used as the delivery news receiving means 5b, it is advantageous in terms of cost and can be recommended. The distribution news received by the distribution news receiving means 5b is I / O6,
It may be stored in, for example, the RAM 7 via the control means 3a. When displaying the distribution news, the control means 3
a is read from the RAM 7 and output to the I / O 6.
The I / O 6 is a normal input / output interface device,
Signals from various data generating means are input to the control means 3a, and the display data output from the control means 3a to the display device 1 is relayed.

In the present invention, the control unit for reading the output signal of the data generating means and switching the data to be input to the display device 1 is configured to include the control means 3a and the switching means 3b. The control means 3a specifically comprises a CPU (not shown) and its peripheral devices (not shown) such as a ROM (not shown). The switching unit 3b is a part of the control unit, and controls the flow of display data to the display device 1 based on the switching control signal from the control unit a. That is, the display data output from the compression / expansion chip 2 and the control means 3a.
The display data that is output from the display device 1 and is output via the I / O 6 is switched and output to the display device 1. This data switching is performed as follows.

FIG. 2 is a schematic view showing an embodiment of a compressed still image display system according to the present invention. It is assumed that the first to fifth screens (JPEG files) are read from the memory card 4 (not shown in FIG. 2), and the five screens are displayed in the reading order. . Here, the compression format of the second screen is B, and the compression formats of the first and third to fifth screens are B.
If the first to fourth sheets are continuously displayed on the display device 1 (not shown in FIG. 2) without implementing the present invention, the first screen and the second screen are displayed. The screen is disturbed. When the first screen of compression format A is displayed, the second screen of compression format B is expanded and the second screen of compression format B is displayed. When is compression format A
This is because the third screen, that is, is expanded. Of course,
The display of the third screen and the display of the fourth screen do not disturb because the screens of the same compression format are expanded behind them.
Therefore, in order to eliminate the disturbance of the screen being displayed, the following is done. The compression / expansion tip 2 (not shown in FIG. 2) is
First, the first screen (JPEG file) in the compression format A is read from the memory card 4 and decompressed. Next, the compression / expansion chip 2 tries to read the second screen (JPEG file) from the memory card 4. Then, it is found that the compression format of the second screen is B different from that of the first screen. The compression / expansion tip 2
The compressed format signal B is output to the control means 3a. Next, almost at the same time as the above operation, the compression / expansion chip 2 outputs the above-described expanded first screen to the display device 1. The switching means 3b (not shown in FIG. 2) is adapted to pass the output from the compression / expansion chip 2 to the display device 1, and the first screen is displayed on the display device 1 (). At this time, the compression / expansion chip 2 does not read or expand the second screen from the memory card 4.
Next, the control means 3a sends the video signal output from the camera 5a (not shown in FIG. 2) to the switching means 3b via the I / O 6 (not shown in FIG. 2), for example.
A switching control signal is transmitted to the switching means 3b to switch the path of the switching means 3b. Therefore, the image from the camera 5a is displayed on the display device 1 ().
The compression / expansion chip 2 reads the second screen from the memory card 4 and expands it while displaying the camera image. Since the camera image is not a JPEG file, the screen is not disturbed. When the compression / expansion chip 2 finishes expanding the second screen, the compression / expansion chip 2 informs the control means 3a of the compression format of the third screen and outputs the second screen to the display device 1. Simultaneously or almost simultaneously, the control means 3a
Switches the path of the switching means 3b. That is, the output data from the compression / expansion chip 2 is displayed on the display device 1 (). The compression / decompression chip 2 does not decompress the third screen when the second screen is displayed. This is because the compression format differs between the second and third screens. When the predetermined display time of the second screen is over, the control means 3a issues a switching command to the switching means 3b and, for example, displays the distribution news (). Distribution news is RAM
Read from 7. Naturally, while displaying the distributed news, the compression / expansion chip 2 reads the third screen (JPEG file) from the memory card 4 and expands it. After that, since the compression format of the JPEG file read from the memory card 4 is the same, the third screen is displayed (), the fourth screen is expanded, and the fourth screen is displayed (). To expand the fifth screen,
You just need to expand and replay it.

As described above, in the system shown in FIG. 1, a screen to be reproduced (displayed) (JPEG file) and a screen to be reproduced next (JPEG file).
If the compression formats of the memory card 4 are different, the next screen is not read and the uncompressed data of the memory card 4 is not expanded.
Video signal from camera 5a, delivery news receiving means 5b
It is possible to display the display data originating from the data generating means on the display device 1, such as the distribution news received in the RAM 7 and stored in the RAM 7. Then, while the data from the data generating means is being displayed on the display device 1, the next screen is read from the memory card 4 and expanded. In this way, the display screen and the decompressed screen have different compression formats, so that the screen is not disturbed.

[0016]

Since the compressed still image display system according to the present invention is configured as described above, it has the following effects. In a compression / decompression method such as JPEG, when a file with a different compression format, for example, the MCU format, is displayed continuously, the inconvenience occurs, that is, while the current screen (data) is being displayed, the next screen ( When the data) is decompressed or expanded, it is possible to prevent the phenomenon that the current screen being displayed is disturbed. In addition, data other than compressed still image data, such as images taken by a camera, is inserted between the current screen that is the target of screen disturbance elimination and the screen that should be displayed next, so screen disturbance is prevented. As a result, it is possible to provide a compressed still image display method in which meaningful images can be continuously displayed, instead of merely a state in which the display of the display device is stopped.

[Brief description of drawings]

FIG. 1 is a block diagram of a compressed still image display system according to the present invention.

FIG. 2 is a schematic diagram showing an embodiment of a compressed still image display system according to the present invention.

[Explanation of symbols]

1 Display device 2 compression / expansion tip 3a Control means 3b switching means 4 memory card 5a camera 5b Delivery news receiving means 6 I / O 7 RAM ,,,, Display order of still screen t time

Claims (2)

[Claims] 1. An image display system having a display device and at least one recording medium, wherein compressed still image data is read from the recording medium,
Decompressing means for executing decompression and display after decompression, data generating means for outputting data to be displayed on the display device, reading an output signal of the data generating means, and switching data to be input to the display device. A control unit,
The decompression unit is configured to output a compression format of the compressed still image file for one screen input to itself, and the control unit reads the compression format and outputs the compression format. A compressed still image display method characterized by having a configuration for controlling data switching. 2. The display system of a compressed still image according to claim 1, wherein the compression of the compressed still image and the expansion by the expansion means are based on the JPEG standard.