JPH0789650B2 - Image processing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image processing apparatus having a plurality of image compression units for compressing image data by mutually different compression methods.

(Prior Art) Conventionally, image data is compressed during image transmission and storage. When the image data is compressed in this way, the compression rate differs depending on the content of the image data. Further, even when the same image data is compressed by different compression methods, the compression rate differs from that of the compression method.

On the other hand, in an image processing apparatus having a plurality of image compression units for compressing image data by different compression methods,
It is necessary to efficiently determine which compression method has a better compression ratio. In particular, it is important in the design of the system how to divide the functions between a plurality of bus-controlled image compression units and the control unit of the entire system.

(Object) The present invention has been made in view of the above points, and in an image processing apparatus in which a plurality of image compression units for compressing image data by different compression methods are connected to a common bus,
The purpose is to efficiently judge which compression method has a better compression ratio.

(Examples) Hereinafter, the present invention will be described in detail with reference to preferred examples.

FIG. 1 shows an embodiment of an image data compression apparatus to which the present invention is applied.

Reference numeral 10 is an image input unit for inputting image data, MPU0 is a control unit for controlling the entire system, and MEM0 is a memory for storing a program for the MPU, image data to be compressed, compressed compressed data and the like. Multiple compression circuits 1 to
N compresses the image data by different compression methods. These MPU0, MEM0, compression circuits 1 to N, image input unit 1
0 is connected via a bus. Reference numeral 11 is an image output unit that outputs compressed image data.

FIG. 2 shows an embodiment of the compression circuits 1 to N shown in FIG.

MPU1 is a control unit that controls the operation of the entire compression circuit.
M1 is a memory that stores compressed data. ROM is M
It is a memory programmed with compression logic such as H, MR, MMR. The counter 21 is a counter that counts the number of data after compression,
The command Reg23 is a register for inputting a command to the compression circuit from the MPU0 shown in FIG. 1 via the driver / receiver 22.

The operation will be described below with reference to the drawings. FIG. 3 is a flow chart showing the operation procedure.

To control the entire apparatus, the image data to be compressed input from the image input unit 10 is stored in MEM0. The stored image data is transferred in parallel to the compression circuits 1 to N, and each compression circuit 1 to N performs compression of each system. At this time, each of the compression circuits 1 to N stores the compressed data in MEM1 and, at the same time, the counter 21 counts the compressed data length.

After waiting for the end of all compression methods, MPU0 compares the counter values of each compression method and determines the compression method with the smallest counter value. By transferring the compressed data stored in MEM1 of the compression circuit of the determined compression method to MEM0, the image data compressed by the best (highest compression efficiency) compression method can be obtained. The compressed data is subjected to post-processing such as transmission and storage by the image output unit 10, but it is omitted in this description. In that case, it goes without saying that the data indicating the compression method of the image data is added and transferred.

FIG. 4 is a flowchart showing the operation of another embodiment according to the present invention.

Another embodiment eliminates or reduces MEM1 in each compression circuit 1-N. Each of the compression circuits 1 to N first causes the counter 21 to count only the data length without storing the compressed data in MEM1 when performing the compression process on the image data. After that, after the compression method is determined by the respective counter values of the respective compression circuits 1 to N, the image data is compressed again by the compression circuit of the determined compression method and compressed. ME data
Transfer to M0.

The above processing is controlled by the MPU 1 according to the contents of the command Reg. In the processing of this other embodiment, the ME of each compression circuit 1-N is
It is possible to minimize or eliminate the capacity of M1.

(Effect) As described above, according to the present invention, in any image compression apparatus, in which image compression apparatuses are connected to a common bus, a plurality of image compression units for compressing image data by different compression methods are used. It is possible to efficiently judge whether the rate is good.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an image data compression device,
FIG. 2 is a diagram showing an embodiment of a compression circuit, FIG. 3 is a flow chart showing the operation procedure of the first illustrated embodiment, and FIG. 4 is a flow chart showing the operation procedure of another embodiment. ,
MPU0 is a control unit, MEM0 is a memory, and 1 to N are compression circuits.

Claims (1)

[Claims] 1. An image input unit for inputting image data, a plurality of image compression units for compressing the image data input by the input unit by mutually different compression methods, a control unit for controlling the entire system, An image output unit that outputs image data compressed by a plurality of image compression units; and a common bus to which the image input unit, the plurality of compression units, the control unit, and the image output unit are connected, Each of the plurality of image compression units is connected to a control circuit that controls the operation of the entire image compression unit, a memory programmed with compression logic, a counter that counts the amount of data after compression, and the common bus. And a connection unit for performing input / output of image data and communication of data with the control unit, wherein the control unit determines a count value of a counter of each of the plurality of image compression units. Zui, the image processing apparatus characterized by compression efficiency to determine the better compression method, to select the image data compressed by the image compression unit of the determined compression method.