JP2001326930A - Image encoder and image encoding method, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the total data transfer rate including the compression time on a network. SOLUTION: The image encoder has a code length estimating means 103 to estimate a code length in the compression of image data from the image data inputted in an input means 102, a threshold table 105 storing an estimated code length in the case of the compression processing of the image data, a compression processing time of the image data, and the transfer rate of the compressed image data, a discriminating means 104 of the use/nonuse of the compression processing to discriminate whether or not the compression processing of the image data is performed by the code length estimated in the code length estimating means 103 by using the threshold table 105, and a compression processing means 106 to perform the compression processing to the image data according to a discriminated result, and an output means 107 to output a flag showing the image data not subjected to the compression processing or the image data subjected to the compression processing and the use/nonuse of the compression processing as coded data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a printer,
The present invention relates to an image encoding apparatus and method effective for compression of a color image used in a scanner, a digital camera, a facsimile, a network, and the like, and a storage medium.

[0002]

2. Description of the Related Art Conventionally, when image data is transferred on a network, the data amount has been increased due to the high definition and colorization of the data, and the data transfer time has been a problem.

[0003] In order to shorten the transfer time, there is an increasing demand for an encoding technique with a high compression ratio.

A conventional technique for transferring image data on a network will be described below.

FIG. 18 is a block diagram showing a conventional process for transferring image data over a network.

First, compression is performed on input image data (S1801) to reduce the data amount. Next, the compressed image data is transferred to another device via the network (S1802). Finally, the device that has received the compressed image data expands the received data (S18).
03), the image data is restored.

[0007]

However, in the above-described conventional technique, since the compression process requires a long calculation time, even if the transfer time on the network is shortened by the reduction in the amount of data by the compression process, the compression time is reduced. The total data transfer time including processing may not be improved compared to the case where data is transferred without performing compression processing.
There is a problem that it is not suitable in an environment where high-speed transfer is required including the compression processing time.

Accordingly, an object of the present invention is to provide an image encoding technique capable of reducing a total data transfer speed including a compression time on a network.

[0009]

In order to solve this problem, an image encoding apparatus according to the present invention comprises: an input unit to which image data is input; and compression of the image data from the image data input to the input unit. Code length estimating means for estimating the code length at the time, a threshold table storing the estimated code length when the image data is compressed, the compression processing time of the image data, and the transfer speed of the compressed image data, Means for determining whether or not to perform compression processing on image data using the code length estimated by the means using a threshold table, and image data in accordance with the determination result of the compression processing use / non-use determination means. Compression processing means for performing compression processing on image data, and image data which has not been subjected to compression processing, or image data which has been subjected to compression processing, and a flag indicating use / non-use of compression processing It is obtained by the configuration and output means for outputting as encoded data.

As a result, the image data having a higher compression rate is compressed for data transfer, and the image data for which the compression rate does not increase is transferred without compression, thereby shortening the compression time on the network. It is possible to reduce the total data transfer time including the data transfer.

[0011]

According to the first aspect of the present invention, an input means to which image data is input, and a code length at the time of compression of the image data is estimated from the image data input to the input means. A code length estimating means, a threshold table storing an estimated code length when the image data is compressed, a compression processing time of the image data, and a transfer speed of the compressed image data; and a code length estimated by the code length estimating means. Compression / non-use determination means for determining whether or not to perform image data compression processing using a threshold table, and compression processing for performing compression processing on image data according to the determination result of the compression / non-use determination means Means for outputting uncompressed image data or compressed image data and a flag indicating use / non-use of compression processing as encoded data An image encoding apparatus having a compression means, and performs image data compression and data transfer with compression rate increasing, and performs image data transfer without increasing compression rate without directly compressing image data. This has the effect that the total data transfer time including the above compression time can be reduced.

According to a second aspect of the present invention, there is provided an input means to which image data is input, an orthogonal transform means for orthogonally transforming the image data inputted to the input means, and a coefficient data by the orthogonal transform means. A code length estimating unit for estimating a code length at the time of compressing the image data, a threshold table storing an estimated code length when the image data is compressed, a compression processing time of the image data, and a transfer speed of the compressed image data; A compression processing use / non-use determination means for determining whether to perform compression processing of image data using the code length estimated by the code length estimation means using a threshold table, and a compression processing use / non-use determination means Compression processing means for performing compression processing on coefficient data according to the result, and use of uncompressed image data or compressed image data and compression processing An image coding apparatus having output means for outputting a flag indicating unused as coded data, and speeding up the processing by performing both code length estimation and compression processing using coefficient data obtained by orthogonal transformation. It has the effect that it becomes possible.

According to a third aspect of the present invention, there is provided an input means for inputting image data, a sub-sampling means for creating a sub-sampling image for the image data input to the input means, and a sub-sampling image. A code length estimating means for estimating a code length of the image data when the image data is compressed, and an estimated code length when the image data is compressed,
A threshold table storing the compression processing time of the image data and the transfer speed of the compressed image data, and determining whether to perform the compression processing of the image data with the code length estimated by the code length estimating unit using the threshold table. Compression processing use / non-use determination means, compression processing means for performing compression processing on image data according to the determination result of the compression processing use / non-use determination means, uncompressed image data or compressed image data And an output unit for outputting a flag indicating use / non-use of compression processing as coded data. The image coding apparatus can determine the code length at high speed and perform efficient data transfer. It has the effect that it becomes possible.

According to a fourth aspect of the present invention, there is provided an input means for inputting image data, and a code length estimating means for estimating a code length of the image data when the image data is compressed from the image data input to the input means. And a threshold table storing an estimated code length when image data is compressed, a compression processing time of the image data, and a transfer speed of the compressed image data, and a network transfer rate obtaining means for obtaining a data transfer rate on a network Compression processing use / non-use determination means for determining whether or not to perform image data compression processing using the code length estimated by the code length estimation means using a threshold value table and a result obtained by the network transfer rate obtaining means. Compression processing means for performing compression processing on image data according to the determination result of compression processing use / non-use determination means;
Output means for outputting uncompressed image data or compressed image data and a flag indicating the use / non-use of the compression process as encoded data as encoded data. Has the effect of enabling the most efficient data transfer to be performed.

According to a fifth aspect of the present invention, there is provided an image processing apparatus, comprising the steps of: inputting image data; estimating a code length of the input image data when the image data is compressed; Prepare a threshold table storing the length, the compression processing time of the image data, and the transfer speed of the compressed image data, and determine whether to perform the compression processing of the image data with the estimated code length using the threshold table. Performs compression processing on image data in accordance with the determination result using the threshold table, and outputs uncompressed image data or compressed image data and a flag indicating use / non-use of compression processing as encoded data. An image encoding method in which image data with a higher compression rate is compressed and transferred, and image data that does not increase in compression rate are compressed as is. By performing data transfer without I has the effect that it becomes possible to shorten the data transfer time of the total, including the compressed time on the network.

According to a sixth aspect of the present invention, image data is input, the input image data is orthogonally transformed, and a code length of the image data at the time of compression is estimated from coefficient data by the orthogonal transformation. Prepare a threshold table that stores the estimated code length when the image data is compressed, the compression processing time of the image data, and the transfer speed of the compressed image data, and perform the compression processing of the image data with the estimated code length. Determine whether or not using a threshold table, perform compression processing on the coefficient data according to the determination result using the threshold table,
This is an image encoding method that outputs uncompressed image data or compressed image data and a flag indicating whether the compression process is used or not used as encoded data, and the code length estimation and the compression process are both orthogonal. By using the coefficient data obtained by the conversion, the processing can be speeded up.

According to a seventh aspect of the present invention, image data is input, a sub-sampling image is created for the input image data, and a code length at the time of compression of the image data is determined from the sub-sampling image. A threshold table storing the estimated code length when the image data is subjected to the compression processing, the compression processing time of the image data, and the transfer speed of the compressed image data is prepared, and the compression processing of the image data is performed using the estimated code length. Using a threshold table to determine whether or not to perform compression, performing compression processing on image data according to the determination result using the threshold table, and using uncompressed image data or compressed image data and compression processing This is an image coding method that outputs a flag indicating / unused as coded data, so that the code length can be determined at high speed and the efficiency is improved. Performing data transfer has the effect that it becomes possible.

According to an eighth aspect of the present invention, there is provided an image processing apparatus, comprising the steps of: inputting image data; estimating a code length of the input image data when the image data is compressed; Prepare a threshold table that stores the length, the compression processing time of the image data, and the transfer speed of the compressed image data, obtain the data transfer rate on the network, and perform the compression processing of the image data with the estimated code length. Whether or not the image data is compressed is determined by using the threshold table and the data transfer rate, and the image data is compressed according to the determination result using the threshold table and the data transfer rate. And an image encoding method for outputting a flag indicating use / non-use of compression processing as encoded data. It has the effect that most efficient be performed with good data transfer is possible in response to changes in the rate.

According to a ninth aspect of the present invention, there is provided an image processing apparatus comprising: a step of inputting image data; a step of estimating a code length of the image data at the time of compression from the input image data; A step of determining whether or not to perform the compression processing of the image data based on an estimated code length when the image data is compressed, a compression processing time of the image data, and a transfer speed of the compressed image data; and Performing a compression process on the image data in accordance with the determination result, and outputting the uncompressed image data or the compressed image data and a flag indicating whether the compression process is used or not as encoded data. Is a storage medium in which a program for executing the image compression is stored. By transferring data without the image data as it is compressed to not rise has the effect that it becomes possible to shorten the data transfer time of the total, including the compressed time on the network.

According to a tenth aspect of the present invention, there is provided an image data input step, an orthogonal transform of the input image data, and a code length at the time of compressing the image data from the coefficient data by the orthogonal transform. And the step of estimating whether or not to perform the compression processing of the image data with the estimated code length, the estimated code length when the image data is compressed, the compression processing time of the image data, and the transfer speed of the compressed image data , A step of performing compression processing on coefficient data in accordance with a result of determination as to whether or not to perform compression processing, and use / non-use of uncompressed image data or compressed image data and compression processing And outputting a flag indicating encoded data as encoded data. Have the effect that it is possible to increase the speed of processing by performing with the coefficient data by the compression process are both orthogonal transformed.

[0021] The invention according to claim 11 of the present invention is characterized in that the step of inputting image data, the step of creating a sub-sampled image for the input image data, and the step of compressing the image data from the sub-sampled image Estimating the code length of the image data, and determining whether or not to perform the compression processing of the image data with the estimated code length, based on the estimated code length when the image data is compressed, the compression processing time of the image data, and the compressed image data. Determining from the transfer speed of the image data, performing a compression process on the image data according to the determination result of whether or not to perform the compression process, and using the uncompressed image data or the compressed image data and the compression process / Outputting a flag indicating unused as coded data. A body, an effect that it is possible to determine the code length at high speed, it is possible to perform efficient data transfer.

According to a twelfth aspect of the present invention, there is provided an image processing apparatus comprising: a step of inputting image data; a step of estimating a code length when the image data is compressed from the input image data; And whether to perform compression processing of the image data with the estimated code length, the estimated code length when the image data is compressed, the compression processing time of the image data, and the transfer speed of the compressed image data. Determining whether to perform compression processing on image data in accordance with the determination result of whether or not to perform compression processing; and determining whether or not image data that has not been subjected to compression processing or compressed image data and compression processing have been performed. Outputting a flag indicating use / non-use as encoded data. A medium, has the effect that most efficient be performed with good data transfer is possible in response to changes in the network transfer rate.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of an image coding apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a block diagram showing an example of the operation of the image encoding device of FIG. 1, FIG. 3 is a block diagram showing an example of the hardware configuration of the image encoding device of FIG. 1, and FIG. FIG. 5 is a block diagram illustrating another example of the hardware configuration, FIG. 5 is a flowchart illustrating an example of encoded data creation processing by the image encoding device in FIG. 3, and FIG. 6 is a diagram illustrating code length estimation in the encoded data creation processing in FIG. FIG. 7 is an explanatory view exemplarily showing a reference pixel to be used, FIG. 7 is an explanatory view showing an encoding configuration using a discrimination flag, image data and compressed data, and FIG. 8 shows another example of the operation of the image encoding apparatus in FIG. FIG. 9 is a block diagram, and FIG. 9 is a flowchart showing another example of the encoded data creation processing by the image encoding device of FIG.

As shown in FIG. 1, the image coding apparatus according to the present embodiment has a control means 101 for controlling the operation of the entire apparatus.
A storage unit 108 storing an operation control program by the control unit 101; an input unit 102 to which image data is input; and estimating a code length of the image data at the time of compression from the image data input to the input unit 102. And a threshold table 10 storing an estimated code length when image data is compressed, a compression processing time of the image data, and a transfer speed of the compressed image data.
5 and whether or not to perform image data compression processing using the code length estimated by the code length estimating means 103,
Compression processing use / non-use determination means 1 for determining by using the method 05
04 and a compression processing unit 1 that performs compression processing on image data in accordance with the determination result of the compression processing use / non-use determination unit 104
06, and output means 1 for outputting uncompressed image data or compressed image data and a flag indicating use / non-use of compression processing as encoded data
07.

The processing flow of the image coding apparatus configured as described above will be described with reference to FIG.

First, the control means 101 is operated by the input means 1
02 receives image data. Then, the code length estimating means 103 estimates the code length of the input image data at the time of compression (S201). Furthermore, the compression processing use / non-use determination unit 104 determines whether to perform compression processing on the image data using the threshold value table 105 (S202).

Then, when it is determined that the compression is to be performed by the compression processing use / non-use determination unit 104, the compression processing unit 106 performs the compression process on the image data (S
203).

Finally, the output means 107 creates encoded data using the image data as input or the image data compressed by the compression processing means 106 and a flag indicating the use / non-use of the compression processing. (S20
4), the encoded data is transferred over the network.

FIG. 3 shows a hardware configuration for realizing the image coding apparatus according to the first embodiment of the present invention.

The image encoding apparatus shown in FIG. 3 has an external storage device 301 in which image data is stored, and a central processing unit (hereinafter referred to as a "CPU") for controlling the operation of the entire apparatus.
302, a read-only memory (hereinafter referred to as “ROM”) 303 having a program storage area and a threshold table storage area, and a random access memory (hereinafter, referred to as “ROM”) having an image storage area and a compression processing use / non-use flag storage area. An output device 305 that outputs uncompressed image data or compressed image data and a flag indicating use / non-use of the compression process as encoded data, Each is bus-connected to each other.

FIG. 3 shows an example of the hardware configuration of an image coding apparatus of an embedded device type. However, when the image coding device is realized by a general-purpose device, it is stored in an external storage device 401 as shown in FIG. A program storage area and a threshold table storage area may be provided. Here, examples of the external storage device 401 include a hard disk, a floppy (registered trademark) disk, a CD-ROM, and an MO. The output device includes a communication port such as a SCSI port, a USB port, a serial port, a parallel port, and a network port.

Next, the flow of encoded data creation processing in the image encoding apparatus having the hardware configuration of FIG. 3 will be described with reference to FIG.

First, when an image stored in the external storage device 301 or the like is input to the image storage area of the RAM 304, the image data is divided into blocks (S501). Note that the blocked image is stored in the image storage area of the RAM 304.

Next, the block number is initialized (S5).
02), the code length of the block data stored in the image storage area at the time of compression is estimated for each block (S50).
3). Then, by comparing the threshold value stored in the threshold value table storage area of the ROM 303 with the code length estimated in S503, it is determined whether or not to perform compression processing (S5).
04). The determination flag indicating whether or not to perform the compression processing is stored in the compression processing use / unused determination flag storage area of the RAM 304.

If it is determined in step S504 that compression processing is to be used, compression processing is performed on the block data stored in the image storage area (S505). The compressed data that has been subjected to the compression processing is stored in the image storage area of the RAM 304. Next, encoded data is created using the discrimination flag stored in the compression processing use / unused discrimination flag storage area and the block data or compressed data stored in the image storage area (S506), and the block number is incremented. (S507). Then, the block number is compared with the block number (S508). If the block number is smaller, the process returns to S503, and the same procedure is repeated for the next block. The above processing is performed using the CPU 302. Finally, the output device 305 outputs the encoded data.

In the above description, the image data is divided into blocks and the processing is performed in units of blocks. However, the processing may be performed in units of lines, bands or images. Therefore, the image data in FIG.
Data in block units, data in line units, data in band units, data in image units, and the like can be considered.

Hereinafter, each block will be described in detail.

First, the code length estimating means 103 estimates the code length in block units. Therefore, calculation of entropy or a coefficient which can be simply substituted for the code length is obtained for each block. For example, as shown in FIG.
Is used to predict the pixel value of the target pixel x by (Equation 1),
A prediction error e, which is a difference value between the predicted value and the actual pixel value of the target pixel x, is obtained by (Equation 2), and the code length is estimated from the sum of the prediction errors e of the pixels in the block. If the sum of the prediction errors in the block is large, the code length becomes large, and if the sum of the prediction errors is small, the code length becomes small.
A table or the like representing the relationship between the sum of the prediction errors and the code length is statistically created in advance, and the code length L is simply calculated from the sum of the prediction errors.
Is estimated.

[0040]

(Equation 1)

[0041]

(Equation 2)

Alternatively, it is conceivable that transform coding such as orthogonal transform is applied to the block data and the code length is estimated using the calculated frequency domain coefficient data. Specifically, a weight Wi of each coefficient is set for the coefficient data si, and the code length L is simply estimated from the coefficient data and the weight using (Equation 3).

[0043]

(Equation 3)

Here, i represents the i-th data in the block, and N represents the total number of data in the block. In addition, a method of actually calculating entropy can be considered.

Next, compression processing use / non-use determination means 10
In step 4, it is determined whether or not to use the compression processing by using the threshold value table 105. Threshold table 105 for determination
Is determined by a trade-off between the estimated code length, the data transfer speed on the network, and the compression processing time.
(Table 1) shows an example of the threshold value table.

[0046]

[Table 1]

Table 1 shows an example of the network transfer speed and the compression time when the data size of one block is 1 MB.

For example, if the network transfer speed is 1000
When kbit / s and the compression time are 2 seconds, 8000/1000 = 8 takes 8 seconds to transfer 1 MB (= 8000 kbit) of data which is one block. Here, since the compression time takes 2 seconds, when compression is performed, 6 seconds (=
If transmission cannot be performed within 8 seconds to 2 seconds), the actual transfer time will be long. Therefore, when the compression process is not performed, the code length is set to 6 bits for an 8 bit / Pixel image.
If it can be compressed to / Pixel or less, the compression is performed. If the code length is not longer than the compression, the compression is not performed. Therefore, when the transfer speed is 1000 kbit / s and the compression time is 2 seconds in the threshold value table, the threshold value is 6.0 bits / Pixel. However, the threshold may be set in consideration of the time required for the code length estimation.

In the case of the network transfer speed and the compression processing time not described in the threshold value table, for example, the network transfer speed is 900 kbit / s and the compression time is 2 kbit / s.
In the case of seconds, the final threshold value is determined by interpolation using adjacent threshold values in the table to be 6.0+ (6.4-6.0) × (9
(00-1000) / (800-1000) = 6.2 and 6.2 may be obtained. Further, in Table 1, when the original image is transferred without being compressed, the total transfer speed including the compression processing time is shorter when the compression processing time is 10 seconds and the network transfer speed is 800 kbit / s or more. In that case, there is no threshold.

The compression processing means 106 uses the compression processing /
When it is determined by the unused determination unit 104 that compression processing is to be performed, compression processing is performed on the input image. As a compression process, a case where transform coding + quantization + entropy coding of an orthogonal transform system is performed like DCT transform of JPEG can be considered, and a case where vector quantization, predictive coding, wavelet transform, or the like is performed is also considered. Can be It is also conceivable to perform lossless compression without deterioration.

If the compression processing time, network transfer speed, and the like are fixed and known in advance, the ROM 303
It is also conceivable that a threshold value suitable for the compression processing time and the network transfer speed is fixedly stored above.

The output means 107 creates encoded data and outputs it. The encoded data includes a flag indicating whether the compression processing is used or not, and image data or compressed data.

FIG. 7 shows an example of actual encoded data. In FIG. 7, the first block is composed of a 1-bit discrimination flag indicating “use of compression processing” and compressed data, and the second block is a 1-bit discrimination flag indicating “unused compression processing” and the original data. It is composed of the same image data as the image data of the same block of the image. In addition, the last block is composed of a 1-bit determination flag meaning "use of compression processing" and compressed data.

As shown in FIG. 8, it is also conceivable that code length estimation is performed after transform coding such as orthogonal transform is performed, and a compression process is performed on an image after the transform coding based on the estimation result. Can be

The flow of the processing at this time will be described with reference to FIG.

In FIG. 5, when an image stored in the external storage device 301 or the like is input to the image storage area of the RAM 304, the image data is divided into blocks (S90).
1). Note that the blocked image is stored in the image storage area of the RAM 304.

Next, the block number is initialized (S9).
02), orthogonal transform is performed for each block on the block data stored in the image storage area (S903). The orthogonally transformed coefficient data is stored in the image storage area of the RAM 304. Then, the code length at the time of compression is estimated using the coefficient data of the orthogonal transform stored in the image storage area (S904). Next, it is determined whether or not to perform the compression process by comparing the threshold value stored in the threshold value table storage area of the ROM 303 with the code length estimated in S904 (S905). The determination flag indicating whether or not to perform the compression processing is stored in the compression processing use / unused determination flag storage area of the RAM 304.

If it is determined in step S905 that the compression process is to be used, the compression process is performed on the coefficient data of the orthogonal transform stored in the image storage area (S906). The compressed data that has been subjected to the compression processing is stored in the image storage area of the RAM 304. Next, encoded data is created using the discrimination flag stored in the compression processing use / unused discrimination flag storage area and the block data or compressed data stored in the image storage area (S907), and the block number is incremented. (S908). Then, the block number is compared with the block number (S909). If the block number is smaller, the process returns to S903, and the same procedure is repeated for the next block. Note that the above processing is performed by the CPU 302.
This is performed using Finally, the output device 305 outputs the encoded data.

In the above description, the image data is divided into blocks and the processing is performed in units of blocks. However, the processing may be performed in units of bands or in units of images. Therefore, the image data in FIG. 8 may be data in block units, data in band units, data in image units, or the like.

As described above, according to the present embodiment, image data having a higher compression rate is subjected to compression and data transfer, and image data having a lower compression rate is transferred without compression. Thus, the total data transfer time including the compression time on the network can be reduced.

If the input image is orthogonally transformed, it is possible to speed up the processing by performing both the code length estimation and the compression processing using the coefficient data by the orthogonal transformation.

(Embodiment 2) FIG. 10 is a block diagram showing the configuration of an image encoding apparatus according to Embodiment 2 of the present invention, FIG. 11 is a block diagram showing the operation of the image encoding apparatus of FIG. 10, and FIG. FIG. 13 is a flowchart showing a coded data creation processing procedure by the image encoding device of FIG. 10, and FIG. 13 is an explanatory diagram showing a sub-sampling operation by a sub-sampling unit in the image encoding device of FIG.

As shown in FIG. 10, the image coding apparatus according to the present embodiment has a control means 10 for controlling the operation of the entire apparatus.
01, a storage unit 1009 storing an operation control program by the control unit 1001, an input unit 1002 to which image data is input, and a sub-sampling for creating a sub-sampled image based on the image data input to the input unit 1002. Means 1003, a code length estimating means 1004 for estimating the code length of the image data at the time of compression from the sub-sampled image created by the sub-sampling means 1003, an estimated code length when the image data is compressed, Threshold table 1006 storing compression processing time and transfer speed of compressed image data
And whether or not image data compression processing is to be performed with the code length estimated by the code length estimating means 1004.
006, a compression processing unit 1007 for performing compression processing on image data according to the determination result of the compression processing use / non-use determination unit 1005, and an image that has not been subjected to compression processing. Use of data or compressed image data and compression processing /
Output means 1008 for outputting a flag indicating unused as encoded data.

The processing flow of the image coding apparatus configured as described above will be described with reference to FIG.

First, the control means 1001 receives image data from the input means 1002. Next, the sub-sampling unit 1003 creates a sub-sampled image of the input image data (S1101). Then, the code length estimating unit 1004 estimates the code length of the compressed image data using the sub-sampled image (S110).
2). Next, compression processing use / non-use determination means 1005
Determines whether to perform compression processing on the image data using the threshold table 1006 (S1103).

If it is determined in S1103 that the compression processing use / non-use determination means 1005 performs compression processing, the compression processing means 1007 performs compression processing on the input image (S1104).

Finally, the output means 1008 creates encoded data using the image data as input or the image data compressed by the compression processing means 1007 and a flag indicating the use / non-use of the compression processing. (S11
05), the encoded data is transferred on the network.

Next, the flow of image encoding by the image encoding device according to Embodiment 2 of the present invention will be described with reference to FIG.

When an image stored in the external storage device 301 or the like is input to the image storage device in the RAM 304,
The image data is divided into blocks (S1201). In addition,
The blocked image is stored in the image storage area of the RAM 304.

Next, the block number is initialized (S1).
202), sub-sampling is performed on the block data stored in the image storage area (S1203). The sub-sampled image is stored in the image storage area of the RAM 304.

Next, the code length at the time of compression is estimated using the sub-sampling data stored in the RAM 304 (S1204), and the threshold value stored in the threshold value table storage area of the ROM 303 and the code length estimated in S1204 are obtained. It is determined whether or not compression processing is performed by comparison (S
1205). The determination flag indicating whether or not to perform the compression processing is stored in the compression processing use / non-use determination flag storage area of the RAM 304.

If it is determined in step S1205 that compression processing is to be used, compression processing is performed on the block data stored in the image storage area (S1206). The compressed data that has been subjected to the compression processing is stored in the image storage area of the RAM 304. Next, encoded data is created using the discrimination flag stored in the compression processing use / unused discrimination flag storage area and the block data or compressed data stored in the image storage area (S1207), and the block number is incremented. (S1208). Then, the block number is compared with the block number (S1209). If the block number is smaller, the process returns to S1203, and the same procedure is repeated for the next block. Note that the above processing is
This is performed using the PU 302. Finally, the output device 305 outputs the encoded data.

In the above description, the image data is divided into blocks and the processing is performed in units of blocks. However, the processing may be performed in units of lines, bands or images. Therefore, the image data in FIG. 11 may be data in block units, data in line units, data in band units, data in image units, or the like.

Hereinafter, the sub-sampling means 1003 will be specifically described. Here, FIG.
(B) shows an example in the case of sub-sampling to 1/2 or 1/4, respectively.

In the case of 1/2 sub-sampling, the peripheral 2 ×
One pixel is extracted from a block of two pixels to create reduced data. Alternatively, a case where the average value of a 2 × 2 pixel block is used is also conceivable. In the 1/4 subsampling, similarly, one pixel is extracted from a peripheral block of 4 × 4 pixels to generate reduced data. Alternatively, a case where the average value of a 4 × 4 pixel block is used is also conceivable.

As described above, according to the present embodiment, sub-sampling of image data is performed, and the code length at the time of compression is estimated using the sub-sampling data. And efficient data transfer can be performed.

(Embodiment 3) FIG. 14 is a block diagram showing a configuration of an image encoding apparatus according to Embodiment 3 of the present invention, FIG. 15 is a block diagram showing an operation of the image encoding apparatus of FIG. 14, and FIG. FIG. 17 is a flowchart showing a procedure of a coded data generation process by the image coding apparatus of FIG. 14, and FIG. 17 is a conceptual diagram showing a data processing program stored in a storage medium.

As shown in FIG. 14, the image coding apparatus according to the present embodiment has a control means 14 for controlling the operation of the entire apparatus.
01, a storage unit 1409 in which an operation control program by the control unit 1401 is stored, an input unit 1402 to which image data is input, and a code length at the time of compression of the image data from the image data input to the input unit 1402. A code length estimating means 1403 for estimating, a threshold table 1405 storing an estimated code length when image data is compressed, a compression processing time of the image data, and a transfer speed of the compressed image data, and a data transfer rate on the network Transfer rate obtaining means 140 for obtaining the
7 and whether or not to perform image data compression processing using the code length estimated by the code length estimating means 1403, the threshold table 1405 and the network transfer rate obtaining means 140
7, a compression processing use / non-use determination unit 1404 that determines using the acquisition result in step 7, and a compression processing use / non-use determination unit 1
A compression processing unit 1406 that performs compression processing on image data according to the determination result of 404, and outputs uncompressed image data or compressed image data and a flag indicating use / non-use of compression processing as encoded data. And output means 1408 for performing the operations.

The processing flow of the image coding apparatus configured as described above will be described with reference to FIG.

First, the control means 1401 receives input image data from the input means 1402. Next, the code length estimating means 1403 estimates the code length at the time of compression using the input image (S1501). Then, the compression processing use / non-use determination unit 1404 determines whether to perform compression processing on the input image using the threshold value table 1405 (S150).
2). At this time, the network transfer rate acquisition means 14
If the previous network transfer rate has been input in step 07, it is determined whether or not to perform compression processing by referring to the threshold value table 1405 using the network transfer rate. If the immediately preceding network transfer rate has not been obtained, it is determined whether or not to perform compression processing by referring to the threshold value table 1405 using the initial value of the network transfer rate. The network transfer rate is initialized in an initial state.

Next, in S1502, the compression processing
If it is determined by the unused determination unit 1404 that compression processing is to be performed, the compression processing unit 1406 performs compression processing on the input image (S1503). Then, output means 1
408 creates encoded data using the input image data or the compressed data by the compression processing unit 1406 and a flag indicating whether the compression processing is used or not (S1504);
The encoded data is transferred over the network.

Network transfer rate acquisition means 1407
Monitors the transmission state of the data transferred on the network, and obtains the time until all the data is transferred and the transmission data amount. Then, the current transfer rate on the network is calculated from the obtained result (S150).
5). The calculated network transfer rate is used for use / non-use determination of the next data compression process.

Next, the flow of image encoding by the image encoding device according to Embodiment 3 of the present invention will be described with reference to FIG.

When an image stored in the external storage device 301 or the like is input to the image storage device in the RAM 304,
The image data is divided into blocks (S1601). In addition,
The blocked image is stored in the image storage area of the RAM 304.

Next, the block number and the network transfer rate are initialized (S1602), and the code length of the block data stored in the image storage area at the time of compression is estimated for each block (S1603). ). Then, referring to the network transfer rate, the ROM 303
It is determined whether or not to perform the compression process by comparing the threshold value stored in the threshold value table with the code length estimated in S1603 (S1604). The determination flag indicating whether or not to perform the compression processing is stored in the compression processing use / unused determination flag storage area of the RAM 304.

If it is determined in S1604 that compression processing is to be used, compression processing is performed on the block data stored in the image storage area (S1605). The compressed data that has been subjected to the compression processing is stored in the image storage area of the RAM 304. Next, encoded data is created using the discrimination flag stored in the compression process use / unused discrimination flag storage area and the block data or compressed data stored in the image storage area (S1606). And output means 30
5 to actually transfer the encoded data over the network,
The current network transfer rate is obtained by monitoring the transfer data amount and transfer time during transfer, and the network transfer rate is updated (S1607).

Next, the block number is incremented (S1608). Then, the block number is compared with the block number (S1609). If the block number is smaller, the process returns to S1603, and the same procedure is repeated for the next block. The above processing is performed using the CPU 302.

In the above description, the image data is divided into blocks and the processing is performed in units of blocks. However, the processing may be performed in units of lines, bands or images. Therefore, the image data in FIG. 15 may be data in block units, data in line units, data in band units, data in image units, or the like.

As described above, according to the present embodiment, it is determined whether or not to perform the compression process by referring to the network transfer rate. Therefore, the most efficient data can be obtained according to the change in the network transfer rate. Transfer can be performed.

FIG. 17 shows a memory map of a storage medium for storing various data processing programs readable by the print processing apparatus according to the embodiment of the present invention.

Although not shown, information for managing a group of programs stored in the storage medium, for example, version information, a creator, etc. are also stored, and information dependent on the OS or the like on the program reading side, for example, a program May be stored.

Further, data dependent on various programs is also managed in the directory. Also, a program for installing various programs on a computer, a program for decompressing a program to be installed when the program to be installed is compressed, and the like may be stored in some cases.

The functions shown in FIG. 5, FIG. 9, FIG. 12, and FIG. 16 in the first, second, and third embodiments are executed by a host computer by a program installed from the outside. Is also good.
In this case, a group of information including a program may be supplied to the output device from a storage medium such as a CD-ROM, a flash memory, or an FD, or from an external storage medium via a network.

As described above, the storage medium storing the program code of the software for executing the above-described processing process is supplied to the system or apparatus, and the computer (or CPU or MPU) of the system or apparatus is stored in the storage medium. The read program code can be read and executed.

In this case, the program code itself read from the storage medium realizes the novel function of the present invention, and the storage medium storing the program code constitutes the present invention.

Examples of the storage medium for supplying the program code include a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, C
DR, magnetic tape, nonvolatile memory card, RO
M, EEPROM and the like can be used.

The computer executes the readout program code to execute not only the above-described processing process but also an OS (Operating System) running on the computer based on the instruction of the program code. It goes without saying that a case where some or all of the actual processing is performed and the above-described process is performed by the processing is also included.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, The CPU provided in the function expansion board or function expansion unit performs part or all of the actual processing,
It goes without saying that a case where the function of the above-described embodiment is realized by the processing is also included.

[0099]

As described above, according to the present invention, image data having a high compression ratio is compressed and transferred.
By transferring image data that does not increase in compression ratio without compressing it as it is, it is possible to reduce the total data transfer time, including the compression time on the network. Can be

If the input image is orthogonally transformed, the code length estimation and the compression processing are both performed using the coefficient data obtained by the orthogonal transformation, so that the processing can be speeded up. can get.

If sub-sampling of image data is performed and the code length at the time of compression is estimated using the sub-sampled data, the code length can be determined at high speed.
An effective effect of enabling efficient data transfer can be obtained.

If it is determined whether or not to perform compression processing with reference to the network transfer rate, the most effective data transfer can be performed in accordance with a change in the network transfer rate. can get.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing an example of the operation of the image encoding device in FIG. 1;

FIG. 3 is a block diagram illustrating an example of a hardware configuration of the image encoding device in FIG. 1;

FIG. 4 is a block diagram showing another example of the hardware configuration of the image encoding device in FIG. 1;

FIG. 5 is a flowchart illustrating an example of encoded data creation processing by the image encoding device in FIG. 3;

FIG. 6 is an explanatory view exemplifying a reference pixel used for code length estimation at the time of the encoded data creation processing in FIG. 5;

FIG. 7 is an explanatory diagram showing an encoding configuration using a discrimination flag, image data, and compressed data.

8 is a block diagram showing another example of the operation of the image encoding device in FIG.

FIG. 9 is a flowchart showing another example of encoded data creation processing by the image encoding device in FIG. 1;

FIG. 10 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 2 of the present invention.

FIG. 11 is a block diagram showing the operation of the image encoding device in FIG. 10;

FIG. 12 is a flowchart showing a coded data creation processing procedure by the image coding apparatus of FIG. 10;

FIG. 13 is an explanatory diagram showing a sub-sampling operation by a sub-sampling unit in the image encoding device of FIG.

FIG. 14 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 3 of the present invention.

FIG. 15 is a block diagram showing the operation of the image encoding device in FIG. 14;

FIG. 16 is a flowchart showing a coded data creation processing procedure by the image coding apparatus of FIG. 14;

FIG. 17 is a conceptual diagram showing a data processing program stored in a storage medium.

FIG. 18 is a block diagram showing a process when image data is conventionally transferred on a network.

[Explanation of symbols]

 102 input means 103 code length estimation means 104 compression processing use / non-use means 105 threshold value table 106 compression processing means 107 output means 1002 input means 1003 sub-sampling means 1004 code length estimation means 1005 compression processing use / non-use determination means 1006 threshold value table 1007 compression processing means 1008 output means 1402 input means 1403 code length estimation means 1404 compression processing use / non-use determination means 1405 threshold table 1406 compression processing means 1407 network transfer rate acquisition means 1408 output means

Claims (12)

[Claims] An input unit for inputting image data; a code length estimating unit for estimating a code length of the image data when the image data is compressed based on the image data input to the input unit; A threshold table storing the estimated code length in the case, the compression processing time of the image data, and the transfer speed of the compressed image data, and whether to perform the compression processing of the image data with the code length estimated by the code length estimation means. Compression processing use / non-use determination means for determining whether or not the image data is used by using the threshold value table; compression processing means for performing compression processing on the image data in accordance with the determination result of the compression processing use / non-use determination means; The image data that has not been compressed or the compressed image data and a flag indicating whether the compression processing is used or not are output as encoded data. The image encoding device characterized by having a force means. 2. An input unit to which image data is input, an orthogonal transform unit for orthogonally transforming the image data input to the input unit, and a code at the time of compressing the image data from coefficient data by the orthogonal transform unit. A code length estimating means for estimating the length, a threshold table storing an estimated code length when the image data is compressed, a compression processing time of the image data, and a transfer speed of the compressed image data, Compression processing use / non-use determination means for determining whether or not to perform compression processing of the image data with the estimated code length using the threshold value table; Compression processing means for performing compression processing on coefficient data; and the image data which has not been subjected to compression processing, or the image data which has been subjected to compression processing and compression Image coding apparatus characterized by an output means for outputting a flag indicating the use / unused processed as encoded data. 3. An input unit to which image data is input, a sub-sampling unit for creating a sub-sampling image for the image data input to the input unit, and when the image data is compressed from the sub-sampling image. Code length estimating means for estimating the code length of the image data, a threshold table storing the estimated code length when the image data is compressed, the compression processing time of the image data, and the transfer speed of the compressed image data, Compression processing use / non-use determination means for determining whether or not to perform compression processing of the image data using the code length estimated by the means using the threshold value table; and determination results of the compression processing use / unuse determination means Compression processing means for performing a compression process on the image data in accordance with Image coding apparatus characterized by an output means for outputting a flag as an encoded data indicating a use / non-use of said image data and compression processing. 4. An input means for inputting image data, a code length estimating means for estimating a code length of the image data at the time of compression from the image data input to the input means, and a process for compressing the image data. A threshold table storing the estimated code length in the case, the compression processing time of the image data, and the transfer speed of the compressed image data; a network transfer rate acquisition unit for acquiring a data transfer rate on a network; and the code length estimation unit. Compression processing use / non-use determination means for determining whether to perform the compression processing of the image data with the estimated code length using the threshold value table and the result obtained by the network transfer rate obtaining means; and the compression processing. Compression processing means for performing compression processing on the image data in accordance with the result of the determination by the used / unused determination means; The image encoding device characterized by having non is the image data or compresses the flag indicating use / not use the image data and compression process and output means for outputting as encoded data. 5. Image data is input, a code length of the image data at the time of compression is estimated from the input image data, an estimated code length when the image data is compressed, a compression processing time of the image data, and A threshold table in which the transfer speed of the compressed image data is stored is prepared, and whether or not to perform the compression processing of the image data with the estimated code length is determined using the threshold table, and the threshold table is used. A compression process is performed on the image data according to the determination result, and the uncompressed image data or the compressed image data and a flag indicating use / non-use of the compression process are output as encoded data. Image encoding method. 6. An image processing method comprising the steps of: inputting image data; orthogonally transforming the input image data; estimating a code length of the image data when the image data is compressed from coefficient data obtained by the orthogonal transformation; A threshold value table storing the code length, the compression processing time of the image data, and the transfer speed of the compressed image data is prepared, and whether or not to perform the compression processing of the image data with the estimated code length is used by using the threshold value table. Performing a compression process on the coefficient data according to the determination result using the threshold value table; a flag indicating whether the image data is not subjected to the compression process or the image data subjected to the compression process and whether or not the compression process is used; Is output as encoded data. 7. Image data is input, a sub-sampling image is created for the input image data, a code length at the time of compression of the image data is estimated from the sub-sampling image, and the image data is compressed. A threshold table storing the estimated code length, the compression processing time of the image data, and the transfer speed of the compressed image data in the case of performing the above is prepared, and it is determined whether or not to perform the compression processing of the image data with the estimated code length. Discriminating using a threshold table, performing compression processing on the image data in accordance with the determination result using the threshold table, and using / not using the uncompressed image data or the compressed image data and the compression processing An image encoding method, comprising outputting a flag indicating use as encoded data. 8. Image data is input, a code length of the image data at the time of compression is estimated from the input image data, an estimated code length when the image data is compressed, a compression processing time of the image data, and Prepare a threshold table storing the transfer speed of the compressed image data, obtain the data transfer rate on the network, and determine whether to perform the compression processing of the image data with the estimated code length. Discriminating using the data transfer rate, performing compression processing on the image data according to the determination result using the threshold value table and the data transfer rate, the image data that has not been subjected to the compression processing or the image data that has been subjected to the compression processing, and An image encoding method characterized in that a flag indicating whether a compression process is used or not is output as encoded data. . 9. A step of inputting image data, a step of estimating a code length of the image data when the image data is compressed from the input image data, and performing a compression process of the image data with the estimated code length. Whether or not the estimated code length when the image data is compressed,
A step of determining from a compression processing time of image data and a transfer speed of the compressed image data; a step of performing compression processing on the image data according to a determination result of whether or not to perform compression processing; and the image not subjected to compression processing. Outputting the data or the compressed image data and a flag indicating the use / non-use of the compression processing as encoded data as a coded data. 10. A step of inputting image data, a step of orthogonally transforming the input image data, and a step of estimating a code length of the image data at the time of compression from coefficient data obtained by the orthogonal transformation. Whether to perform the compression processing of the image data with a code length, an estimated code length when the image data is compressed,
A step of determining from a compression processing time of image data and a transfer speed of the compressed image data; a step of performing compression processing on the coefficient data according to a determination result of whether or not to perform compression processing; and Outputting the data or the compressed image data and a flag indicating the use / non-use of the compression processing as encoded data as a coded data. 11. A step of inputting image data, a step of creating a sub-sampling image for the input image data, and a step of estimating a code length of the image data at the time of compression from the sub-sampling image. Whether or not to perform the compression processing of the image data with the estimated code length, an estimated code length when the image data is compressed,
A step of determining from a compression processing time of image data and a transfer speed of the compressed image data; a step of performing compression processing on the image data according to a determination result of whether or not to perform compression processing; and the image not subjected to compression processing. Outputting the data or the compressed image data and a flag indicating the use / non-use of the compression processing as encoded data as a coded data. 12. A step of inputting image data, a step of estimating a code length at the time of compression of the image data from the input image data, and a step of obtaining a data transfer rate on a network. Whether to perform the compression processing of the image data with a code length, an estimated code length when the image data is compressed,
Determining a compression processing time of the image data, a transfer speed of the compressed image data, and the data transfer rate; performing a compression process on the image data in accordance with a determination result of whether to perform the compression process; Outputting the unprocessed image data or the compressed image data and a flag indicating use / non-use of the compression process as encoded data as encoded data. .