JP2004125866A - Image display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of quickly monitor displaying images at an expected moment in an image display device for displaying compressed images. <P>SOLUTION: In a FLASH memory 2, compressed image data AD are stored. In starting the image display device 10, a CPU 1 decompresses the compressed image data AD and stores them as image data BD in a main memory 3. In the operation state of the image display device 10, the CPU 1 instructs a display controller IC 4 to display the images when an image display instruction is irregularly supplied from the outside. The display controller IC 4 reads the image data BD stored in the main memory 3, generates plotting data in an image memory 5 and displays the plotting data on a display panel 6. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for displaying a compressed image by an image display device.
[0002]
[Technical background and problems to be solved by the invention]
In an image display device that displays image data, the image data is stored as compressed image data in order to save the capacity of a memory or a hard disk. Then, when displaying an image, a process of expanding the compressed image data and restoring the original image data is performed.
[0003]
If a general user refers to an image using a personal computer or the like, such a high speed is not required, so that the decompression processing time of the compressed image does not become a fatal problem.
[0004]
However, there is a case where the image display device is required to have a high speed of image display. For example, there is a case where an image display device installed in an elevator is required to immediately display a message suitable for the arrival floor according to the arrival floor of the elevator.
[0005]
Since the elevating operation of the elevator is determined by the designation operation of the passenger, information as to when and on which floor the vehicle will arrive cannot be obtained until immediately before.
[0006]
In FIG. 4, time t1 is a time at which information about the number of arrival floors is obtained, and time t2 is a time at which an image is expected to be displayed. The period a is a period for decompressing compressed image data, and the period b is a period for displaying image data.
[0007]
In the process shown in this figure, the compressed image data is stored in the FLASH memory or the hard disk, and the decompression process is performed at time t1 from the time when the information on the arrival floor is obtained. Therefore, at the time when the decompression process and the display process are completed, the time t2 at which the image is expected to be displayed has passed.
[0008]
Here, the expansion processing period of the compressed image data such as JPEC depends on the original image being compressed. Therefore, depending on the original image, the decompression process period may be short, and the decompression process and the display process may end by time t2. In such a case, the display processing is performed at the expected time t2. However, depending on the original image, a situation as shown in FIG. 4 occurs, and the image processing is slightly delayed from the expected time. The display was done. That is, since the expansion processing period changes depending on the content of the original image, the maximum time until the compressed image is displayed cannot be specified.
[0009]
Further, since the compressed image data is stored in the FLASH memory or the hard disk which has a slower access process than the RAM, there is a problem that the data reading time is long.
[0010]
In view of the foregoing, the present invention has been made in view of the above-described problem, and has been made in view of the above-described problem. The purpose is to provide.
[0011]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 is a method for displaying a compressed image on a monitor by an image display device, wherein the compressed image stored in the first storage means at the time of activation of the image display device. Expanding the data and storing the decompressed image data in a second storage means; and, when the image display device is operating, operating a monitor based on the image data stored in the second storage means. Performing an image display process.
[0012]
According to a second aspect of the present invention, in the image display method according to the first aspect, the second storage means is a storage means for accessing data at a higher speed than the first storage means. And
[0013]
According to a third aspect of the present invention, in the image display method according to the first or second aspect, the second storage means includes a main memory of the image display device.
[0014]
According to a fourth aspect of the present invention, in the image display method according to any one of the first to third aspects, an instruction to display an image on the image display device is issued to an operation of a predetermined device including the image display device. It is characterized by being generated irregularly in response.
[0015]
According to a fifth aspect of the present invention, in the image display method of the fourth aspect, the compressed image data is decompressed during a period from when the display instruction is issued until an image is expected to be displayed. The period is shorter than the period obtained by adding the period and the period for displaying the expanded image data.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
<Outline of device functions>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram of the image display device 10.
[0017]
The image display device 10 includes a CPU 1, a flash memory (flash-EEPROM) 2, a main memory 3, a display control IC 4, an image memory (VRAM) 5, a display panel 6, and the like. These components are connected via a CPU bus, a memory bus, or the like.
[0018]
The FLASH memory 2 stores compressed image data AD which is compressed data of an image to be displayed by the image display device 10. When various images are displayed on the image display device 10, the compressed image data AD indicates compressed data of a plurality of images. As a data format of the compressed image data AD, for example, JPEG exists.
[0019]
The main memory 3 is composed of, for example, a DRAM or the like, and stores image data BD as decompressed data after expanding the compressed image data AD.
[0020]
The display control IC 4 has a function of generating drawing data in the image memory 5 and a function of displaying the drawing data generated in the image memory 5 on the display panel 6 according to an image display command from the CPU 1.
[0021]
The CPU 1 has a function of expanding the compressed image data AD, a function of instructing the display controller IC 4 to display an image, and the like.
[0022]
As shown in FIG. 2, in the present embodiment, the image display device 10 is installed for guidance display of the elevator 20. Then, information on the number of arrival floors of the elevator 20 is transferred from the sensor 21 provided in the elevator 20 to the image display device 10.
[0023]
In the image display device 10, when the information regarding the number of arrival floors is received from the sensor 21, the CPU 1 determines a display image and sends an image display command to the display controller IC4.
[0024]
<Process flow>
The flow of an image display process in the image display device 10 having the above configuration will be described.
[0025]
First, when the power is turned on and the image display device 10 is started, the CPU 1 executes a decompression process of the compressed image data AD stored in the flash memory 2. Then, the restored image data BD after decompression is stored in the main memory 3. As described above, in the present invention, at the time of startup (that is, before the image display device 10 starts an actual operation), the decompression processing of the compressed image data AD is performed for all the images to be displayed, and All the image data BD are stored in the main memory 3.
[0026]
Note that the image display device 10 is activated when a device including the image display device 10 is activated. Therefore, in the case of the present embodiment, the image display device 10 is activated in accordance with the operation start time of the elevator 20.
[0027]
The operation of the elevator 20 is started in a state where the expansion processing of the compressed image data AD is completed and the image data BD is stored in the main memory 3, and the image display device 10 is also in the operating state.
[0028]
Next, when the elevator 20 moves up and down according to the passenger's operation instruction and approaches a certain floor, the sensor 21 transmits information on the floor to the image display device 10. The information on the floor number transmitted from the sensor 21 corresponds to an image display instruction given to the image display device 10. As described above, the image display device 10 receives an instruction to display an image irregularly by the operation of the elevator 20.
[0029]
In the image display device 10, when receiving an instruction from the sensor 21, the CPU 1 determines the display content of the image according to the floor, and issues an image display command to the display control IC 4.
[0030]
Upon receiving an image display command from the CPU 1, the display control IC 4 reads the corresponding image data BD from the main memory 3 and generates drawing data on the image memory 5. Then, the display controller IC 4 displays the generated drawing data on the display panel 6.
[0031]
As described above, according to the present embodiment, since the compression processing of the compressed image data AD is performed when the image display device 10 is activated as shown in FIG. 3 (period A), the information about the floor is received from the sensor 21. At the time, that is, at the time T1 at which the image display instruction is received, the expanded image data BD is already stored in the main memory 3. As a result, the image display device 10 can immediately execute the image display processing from the time T1.
[0032]
Therefore, in the present embodiment, the decompression processing period of the compressed image data AD to be displayed is long, and the period from time T1 at which an image display instruction is received to time T2 from when the image is expected to be displayed is equal to the image display time. Even if the period is shorter than the period obtained by adding the expansion processing period A and the image display processing period B, at the time when the image display processing period B ends, the time T2 at which image display is expected. Has not passed. That is, if an image display instruction is obtained so that the period B required for the image display processing can be secured at a minimum, the image can be displayed at the expected time T2.
[0033]
In other words, by executing the decompression processing when the image display device 10 is activated, the problem that the maximum time until the display of the compressed image data AD cannot be specified because the decompression processing period differs depending on the content of the original image is solved. It is.
[0034]
Then, even when an image display instruction is transmitted from the elevator 20 irregularly as in the present embodiment, the image display processing can be executed immediately after receiving the image display instruction. This makes it possible to display an image at the expected time T2.
[0035]
Further, according to the present embodiment, the decompressed image data BD is stored in the main memory 3 composed of a DRAM or the like having an access speed higher than that of the FLASH memory, so that the processing speed can be further reduced. is there.
[0036]
Further, in the present embodiment, the FLASH memory 2 is used as the storage means of the compressed image data AD. However, since the reading of the compressed image data AD is performed at the time of startup where high speed is not required, the compressed image data AD It may be stored in a magnetic memory such as a hard disk.
[0037]
【The invention's effect】
As described above, according to the first aspect of the present invention, when the image display device is activated, the compressed image data is expanded and the expanded image data is stored in the second storage means. Is performed, it is not necessary to perform image decompression processing, and the processing can be speeded up.
[0038]
According to the second aspect of the present invention, since the second storage means for storing the image data is faster in data access processing than the first storage means, the image display processing is further speeded up. It is possible.
[0039]
According to the third aspect of the present invention, since the second storage means is the main memory of the image display device, the CPU can immediately execute the display processing when performing the image display processing.
[0040]
According to the fourth aspect of the present invention, the image display instruction to the image display device is generated at irregular intervals in accordance with the operation of a predetermined device provided with the image display device. Although a sufficient processing time cannot be secured, according to the present invention, since the compressed image is decompressed in advance, it is possible to display the image at the expected time.
[0041]
According to the fifth aspect of the present invention, the period from when the display instruction is issued to when the image is expected to be displayed is shorter than the period required for the decompression processing and the display processing. When the processing is performed, it is impossible to display the image at the expected time. However, according to the present invention, the compressed image is decompressed in advance, so that the image is displayed at the expected time. Is possible.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of an image display device.
FIG. 2 is a diagram showing an image display device provided in the elevator.
FIG. 3 is a diagram showing a display sequence of an image by the image display device of the present invention.
FIG. 4 is a diagram showing a display sequence of an image by a conventional image display device.
[Explanation of symbols]
1 CPU
2 FLASH memory 3 Main memory 4 Display control IC
5 Image memory 6 Display panel

Claims (5)

A method of displaying a compressed image on a monitor by an image display device,
Expanding the compressed image data stored in the first storage means and storing the expanded image data in the second storage means when the image display device is activated;
Performing a process of displaying an image on a monitor based on the image data stored in the second storage unit during operation of the image display device;
An image display method comprising: The image display method according to claim 1,
The image display method according to claim 1, wherein said second storage means is a storage means for accessing data at a higher speed than said first storage means. In the image display method according to claim 1 or 2,
The image display method, wherein the second storage unit includes a main memory of the image display device. The image display method according to any one of claims 1 to 3,
An image display method, wherein an instruction to display an image on the image display device is generated irregularly in accordance with an operation of a predetermined device including the image display device. The image display method according to claim 4,
A period from the time when the display instruction is generated until an image is expected to be displayed is shorter than a period obtained by adding a period for expanding the compressed image data and a period for displaying the expanded image data. An image display method characterized by being a period.

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