JP2000115767A - Image data communication device and image data processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image data communication device that can receive image data even when an idle capacity of an image storage memory of a reception section is smaller than a data size of received image data. SOLUTION: The image data communication device has a reception section 1A, which has a coder 5 that applies compression coding to received uncompressed image data, an image storage memory 4 that stores compressed and coded image data and a central control section 3 that controls the entire component of the reception section 1A. The central control section 3 controls Q value of the coder 5 in response to an idle capacity of the image storage memory 4 so as to reduce the quantity of image data stored in the image storage memory 4 to a level less than the quantity of the uncompressed image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image data communication apparatus and an image data processing method for receiving and storing compressed and uncompressed image data.

[0002]

2. Description of the Related Art Conventionally, image data from a transmission section of an image data communication apparatus as a transmission terminal is received in the same size by a reception section of the image data communication apparatus as a reception terminal, and image storage of the reception section is performed. Was stored in memory.
Hereinafter, the configuration and operation of a conventional image data communication device will be described with reference to the drawings.

FIG. 8 is a block diagram showing a receiving section of a conventional image data communication device. In FIG. 8, 1C is a receiving unit of the image data communication device, 2 is a line interface,
Denotes a CPU serving as a central control unit for controlling communication with a transmission unit (not shown) of the image data communication apparatus serving as a transmission terminal and image processing, 4 denotes an image storage memory for storing image data, and N denotes communication. It is a net.

[0004] The operation of the receiving section 1C of the image data communication apparatus thus configured will be described with reference to FIG.
FIG. 9 is a flowchart showing the operation of the receiving section 1C shown in FIG.

[0005] The image data v from the transmitting unit of the image data communication device as the transmitting terminal is received by the receiving unit 1C as the receiving terminal through the communication network N (S21). CPU3
Compares the data size of the received image data v with the free space of the image storage memory 4 (S22), and determines whether the remaining capacity (free space) of the image storage memory 4 is sufficient (S22).
23). If the free space of the image storage memory 4 is smaller than the data size of the image data v, the reception becomes impossible (S
24) If the free space of the image storage memory 4 is larger than the data size of the image data v, the image data of the same size is stored in the image storage memory 4 (S2).
5).

[0006]

As described above, in the conventional image data communication apparatus, if the free space of the image storage memory 4 of the receiving unit is smaller than the data size of the received image data v, the image cannot be received. Had.

In this image data communication apparatus and image data processing method, it is required that the image data can be received even when the free space of the image storage memory of the receiving unit is smaller than the data size of the received image data.

According to the present invention, an image data communication apparatus capable of receiving even when the free space of the image storage memory of the receiving unit is smaller than the data size of the received image data, and the free space of the image storage memory of the receiving unit It is an object of the present invention to provide an image data processing method that enables reception even when the data size is smaller than the data size of the received image data.

[0009]

In order to solve this problem, an image data communication apparatus according to the present invention comprises an encoder for compressing / encoding received non-compressed image data and storing the compressed / encoded image data. An image data communication device having an image storage memory to perform and a central control unit for controlling the whole in a receiving unit, wherein the central control unit controls a Q value of an encoder according to a free space of the image storage memory. And a configuration for reducing the amount of image data stored in the image storage memory from the amount of uncompressed image data.

Thus, an image data communication apparatus capable of receiving even when the free space of the image storage memory of the receiving unit is smaller than the data size of the received image data is obtained.

According to another aspect of the present invention, there is provided an image data processing method for compressing and encoding received uncompressed image data and storing the compressed and encoded image data in an image storage memory. A configuration in which the Q value in the compression / encoding is controlled in accordance with the free space of the image storage memory so that the amount of image data stored in the image storage memory is smaller than the amount of uncompressed image data. I have.

Thus, there is provided an image data processing method which enables reception even when the free space of the image storage memory of the receiving unit is smaller than the data size of the received image data.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image data communication apparatus according to a first aspect of the present invention comprises an encoder for compressing and encoding received non-compressed image data, and an image storage for storing compressed and encoded image data. An image data communication device having a memory and a central control unit for controlling the whole in a receiving unit, wherein the central control unit controls a Q value of an encoder according to a free space of an image storage memory to store an image. The amount of image data to be stored in the memory is made smaller than the amount of uncompressed image data. The uncompressed image data is compressed according to the Q value of the encoder, and stored according to the Q value. This has the effect of reducing the amount of image data.

[0014] According to a second aspect of the present invention, there is provided an image data communication apparatus.
A decoder that decodes the received compressed image data, an encoder that compresses and encodes the decompressed image data obtained by decoding the compressed image data by the decoder, and stores the compressed and encoded image data An image data communication device having an image storage memory and a central control unit for controlling the whole in a receiving unit, wherein the central control unit controls a Q value of an encoder according to a free space of the image storage memory, The amount of image data to be stored in the image storage memory is set to be smaller than the amount of compressed image data. The decompressed image data is compressed according to the Q value of the encoder, and stored according to the Q value. This has the effect of reducing the amount of image data.

According to a third aspect of the present invention, there is provided the image data communication apparatus,
A decoder that dequantizes received compressed image data and outputs dequantized image data, quantizes the dequantized image data, and an encoder that compresses and encodes, and stores the compressed and encoded image data An image data communication device having an image storage memory and a central control unit for controlling the whole in a receiving unit, wherein the central control unit controls a Q value of an encoder according to a free space of the image storage memory, This is to reduce the amount of image data stored in the image storage memory from the amount of compressed image data, and has the effect of directly quantizing the dequantized image data in the decoder according to the Q value. Have.

According to a fourth aspect of the present invention, there is provided an image data processing method comprising:
An image data processing method for compressing / encoding received non-compressed image data and storing the compressed / encoded image data in an image storage memory, wherein a Q value in compression / encoding is determined according to a free space of the image storage memory. Control to reduce the amount of image data stored in the image storage memory from the amount of uncompressed image data, and the uncompressed image data is compressed according to the Q value in encoding. This has the effect that the amount of accumulated image data decreases according to the Q value.

According to a fifth aspect of the present invention, there is provided an image data processing method comprising:
Decompress the received compressed image data, and decompress the decompressed image data obtained by decoding the compressed image data.
An image data processing method for storing encoded and compressed / encoded image data in an image storage memory, wherein a Q value in compression / encoding is controlled in accordance with a free space of the image storage memory, and the image data is stored in the image storage memory. The amount of image data to be stored is set to be smaller than the amount of compressed image data. The expanded image data is compressed according to the Q value of the encoder, and the amount of stored image data is reduced according to the Q value. It has the effect of decreasing.

According to a sixth aspect of the present invention, there is provided an image data processing method comprising:
The received compressed image data is dequantized to generate dequantized image data, and the dequantized image data is quantized and compressed.
An image data processing method for storing encoded and compressed / encoded image data in an image storage memory, wherein a Q value in compression / encoding is controlled in accordance with a free space of the image storage memory, and the image data is stored in the image storage memory. The amount of image data to be stored is made smaller than the amount of compressed image data, and has the effect of directly quantizing the inversely quantized image data in the decoder according to the Q value.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. (Embodiment 1) FIG. 1 is a block diagram showing a receiving section of an image data communication apparatus according to Embodiment 1 of the present invention. In FIG. 1, the line interface 2, CPU 3, image storage memory 4, and communication network N are the same as those in FIG. 1A is a receiving unit, and 5 is an encoder that compresses and encodes the non-compressed image data v1 in real time while receiving it.

FIG. 2 is a block diagram showing in detail an encoder constituting the receiving section of the image data communication apparatus shown in FIG. In FIG. 2, 6 is a discrete cosine transformer for transform-encoding image data, 7 is a quantizer for reducing the number of effective coefficients of DCT coefficients, and 8 is an optimal compressed image obtained by entropy-encoding the quantized DCT coefficients. A Huffman encoder 9 for generating the data va is a Q-value controller 9 for controlling the image quality of the image data and the amount of encoded information.

The operation of the receiving section 1A of the image data communication apparatus thus configured will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of the receiving section 1A of the image data communication device shown in FIGS.

In FIG. 3, when the receiving section 1A starts receiving the non-compressed image data v1 (S1), the CPU 3
The free capacity of the image storage memory 4 managed by the PU 3 is compared with the data amount (data size) of the uncompressed image data v1 being received (S2), and the remaining capacity (free capacity) of the image storage memory 4 is sufficient. It is determined whether or not (S3). When it is determined in step 3 that the free space is smaller than the received data amount, the CPU 3 sets the Q value of the Q value controller 9 to a large value in accordance with the free space of the image storage memory 4, that is, when the free space is large, the Q value is increased. The compression ratio is set small to reduce the compression ratio, and when the free space is small, the Q value is set large to increase the compression ratio. The uncompressed image data v1 is encoded by the encoder 5
, And the number of effective coefficients of the DCT coefficients is reduced by using the quantizer 7 according to the Q value set according to the free space. The quantized DCT coefficients are entropy-encoded by the Huffman encoder 8 to reduce the image quality of the image data and reduce the amount of encoded information to achieve high compression, thereby generating optimal compressed image data va (S4). Further, the high-compression image data va is transferred to the image storage memory 4 and held as image data (S5).

As described above, according to this embodiment, the amount of image data newly stored in the image storage memory 4 is controlled by controlling the Q value of the encoder 5 according to the free space of the image storage memory 4. Can be made smaller than the data amount of the non-compressed image data v1, so that even if the free space of the image storage memory 4 is smaller than the data size of the received non-compressed image data v1, it becomes possible to receive.

(Embodiment 2) FIG. 4 is a block diagram showing a receiving section of an image data communication apparatus according to Embodiment 2 of the present invention. In FIG. 4, line interface 2, C
The PU 3, the image storage memory 4, the encoder 5, and the communication network N are the same as those in FIG. 1B is a receiving unit, and 10 is a decoder that performs entropy decoding contrary to encoding.

FIG. 5 is a block diagram showing the decoder 10 constituting the receiving section 1B of FIG. In FIG. 10, 11
Is a Huffman decoder that performs entropy decoding contrary to encoding, 12 is an inverse quantizer that performs inverse quantization to generate inversely quantized image data, and 13 is an expanded image data that performs inverse discrete cosine transform. This is an inverse discrete cosine transformer that generates vb. Note that the encoder constituting the receiving unit 1B in FIG. 4 is the encoder shown in FIG. 2, as in the first embodiment.

The operation of the receiving section of the image data communication apparatus thus configured will be described with reference to FIG.
FIG. 6 is a flowchart showing the operation of the receiving section 1B of the image data communication device shown in FIGS.

In FIG. 6, when the reception of the irreversible compressed image data v2 is started (S11), the CPU 3
The free capacity of the image storage memory 4 managed by the PU 3 is compared with the data amount of the compressed image data v2 being received (S12), and the remaining capacity (free capacity) of the image storage memory 4 is determined.
It is determined whether or not is sufficient (S13). If it is determined in step 13 that the free space is smaller than the received data amount,
Next, the CPU 3 determines whether or not the file is an uncompressed file (that is, whether or not it is uncompressed image data) (S14). Step 13
And the free space of the image storage memory 4 is
2 is smaller than the data amount, and
If it is determined that the received image data is compressed image data, the lossy compressed image data v2 is
0 is subjected to entropy decoding by the Huffman decoder 11, inversely quantized by the inverse quantizer 12, and inversely discrete cosine transformed by the inverse discrete cosine transformer 13 (S 1).
5), decompressed and decoded image data (decompressed image data) v
Output as b. Next, the decompressed image data vb is transformed and encoded by the discrete cosine transformer 6 of the encoder 5. If it is determined in step 14 that the received image data is the non-compressed image data v1,
1 is also transform-encoded by the discrete cosine transformer 6 of the encoder 5. For the transform-encoded image data, C
The PU 3 sets the Q value of the Q value controller 9 according to the free space of the image storage memory 4, thereby reducing the number of effective DCT coefficients using the quantizer 7. The quantized DCT coefficients are entropy-encoded by the Huffman encoder 8 to reduce the image quality of the image data, reduce the amount of encoded information, and perform high compression to generate optimal compressed image data va (S16). Further, the high-compression image data va is transferred to the image storage memory 4 and held as image data (S17). If it is determined in step 13 that the free space of the image storage memory 4 is sufficient, the compressed image data v2 is stored in the image storage memory 4 as it is, as in the related art.

As described above, according to the present embodiment, the Q value of the encoder 5 is controlled in accordance with the free space of the image storage memory 4 so that the amount of image data to be stored in the image storage memory 4 can be reduced. Of the decompressed image data v output from the decoder 10
b can be compressed and encoded according to the Q value of the encoder so that the amount of image data to be stored can be smaller than the free space of the image storage memory 4. Reception is possible even if it is smaller than the data size of the reception compressed image data v2.

(Embodiment 3) FIG. 7 is a block diagram showing an encoder and a decoder constituting a receiving section of an image data communication apparatus according to Embodiment 3 of the present invention. In FIG. 7, an encoder 5, a discrete cosine transformer 6, a quantizer 7,
The Huffman encoder 8, the Q value controller 9, the Huffman decoder 11, the inverse quantizer 12, and the inverse discrete cosine transformer 13 are the same as those in FIG. 2 and FIG. Omitted. 10A is a decoder, and 14 is a changeover switch for directly switching the path of the data (inversely quantized image data) inversely quantized by the inverse quantizer 12 to the input side of the quantizer 7.

The operation of the receiving section of the image data communication apparatus thus configured will be described with reference to the flowchart of FIG.

In FIG. 6, when the reception of the irreversible compressed image data v2 is started (S11), the CPU 3
The free capacity of the image storage memory 4 managed by the PU 3 is compared with the data amount of the compressed image data v2 being received (S12), and the remaining capacity (free capacity) of the image storage memory 4 is determined.
It is determined whether or not is sufficient (S13). If it is determined in step 13 that the free space is smaller than the received data amount,
Next, the CPU 3 determines whether or not the file is an uncompressed file (that is, whether or not it is uncompressed image data) (S14). Step 13
And the free space of the image storage memory 4 is
2 is smaller than the data amount, and
If it is determined that the received image data is compressed image data, the lossy compressed image data v2 is
Entropy decoding is performed by the Huffman decoder 11 of 0, and inverse quantization is performed by the inverse quantizer 12 to obtain inverse quantized image data a (S15). Inverse quantized image data a
Is directly sent to the quantizer 7 of the encoder 5 by the changeover switch 14. For the inverse quantized image data a, C
The PU 3 sets the Q value of the Q value controller 9 according to the free space of the image storage memory 4, thereby reducing the number of effective DCT coefficients using the quantizer 7. The quantized DCT coefficients are entropy-encoded by the Huffman encoder 8 to reduce the image quality of the image data, reduce the amount of encoded information, and perform high compression to generate optimal compressed image data va (S16). Further, the high-compression image data va is transferred to the image storage memory 4 and held as image data (S17). Note that, in the present embodiment, the uncompressed image data v1 is compressed and encoded by the encoder 5 as shown in FIG. In this case, the changeover switch 14 is connected to the upper contact, and the decoder 10A does not participate in the processing operation of the image data.

As described above, according to the present embodiment, the dequantized image data generated by the decoder 10A is directly input to the quantizer 7 of the encoder 5 to be quantized, and compressed / encoded. By storing the compressed and encoded image data in the image storage memory 4, the decoding and encoding of the image data can be performed in a shorter time than in the second embodiment. it can.

[0033]

As described above, according to the image data communication apparatus of the first aspect of the present invention, the encoder for compressing and encoding the received non-compressed image data and the image data for compressing and encoding the received uncompressed image data are transmitted. An image data communication device having an image storage memory for storing and a central control unit for controlling the whole in a receiving unit, wherein the central control unit controls a Q value of an encoder according to a free space of the image storage memory. By reducing the amount of image data stored in the image storage memory from the amount of uncompressed image data, the amount of image data stored in the image storage memory can be made equal to or less than the free space of the image storage memory. Even if the free space of the image storage memory is smaller than the data size of the received uncompressed image data,
An advantageous effect that reception becomes possible is obtained.

According to the image data communication apparatus of the present invention, the decoder for decoding the received compressed image data and the decompressed image data obtained by decoding the compressed image data by the decoder are compressed and decoded. An image data communication device having an encoder for encoding, an image storage memory for storing compressed and encoded image data, and a central control unit for controlling the whole in a receiving unit, wherein the central control unit includes an image storage memory By controlling the Q value of the encoder according to the free space of the compressed image data to reduce the amount of image data stored in the image storage memory from the amount of compressed image data, the expanded image data output from the decoder is controlled. Can be compressed and coded according to the Q value of the encoder, and the amount of image data stored in the image storage memory can be made equal to or less than the free space of the image storage memory. Advantageous effect even when less than the data size of the compressed image data becomes receivable is obtained.

According to the image data communication apparatus of the third aspect, a decoder that dequantizes the received compressed image data and outputs the dequantized image data, quantizes the dequantized image data, and performs compression / decompression. An image data communication device having an encoder for encoding, an image storage memory for storing compressed and encoded image data, and a central control unit for controlling the whole in a receiving unit, wherein the central control unit includes an image storage memory Decoding and encoding of image data by controlling the Q value of the encoder in accordance with the free space of the image data to reduce the amount of image data stored in the image storage memory to the amount of compressed image data. Can be carried out in a short time.

According to a fourth aspect of the present invention, there is provided an image data processing method for compressing and encoding received non-compressed image data and storing the compressed and encoded image data in an image storage memory. , Q in compression / encoding
By controlling the value in accordance with the free space of the image storage memory and reducing the amount of image data stored in the image storage memory to the amount of uncompressed image data, the amount of image data stored in the image storage memory is reduced. Since it is possible to reduce the free space of the storage memory to less than the free space of the image storage memory, an advantageous effect is obtained that even if the free space of the uncompressed image data is smaller than the data size of the received non-compressed image data, the image can be received.

According to the image data processing method of the present invention, the received compressed image data is decoded.
An image data processing method for compressing / encoding decompressed image data obtained by decoding compressed image data and storing the compressed / encoded image data in an image storage memory. By controlling the amount of image data stored in the image storage memory to be smaller than the amount of compressed image data by controlling according to the free space of the storage memory, the decompressed image data output from the decoder is Since the amount of image data to be stored in the image storage memory after compression / encoding according to the Q value can be made equal to or less than the free space of the image storage memory, the free space of the image storage memory is larger than the data size of the received compressed image data. Has an advantageous effect that reception is possible even when the size is small.

According to the image data processing method of the present invention, the received compressed image data is dequantized to generate dequantized image data, and the dequantized image data is quantized.
An image data processing method for compressing / encoding and storing compressed / encoded image data in an image storage memory, wherein the Q value in the compression / encoding is controlled according to the free space of the image storage memory to store the image. By reducing the amount of image data stored in the memory to the amount of compressed image data, the advantageous effect that decoding and encoding of image data can be performed in a short time can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a receiving unit of an image data communication device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an encoder constituting the receiving unit of FIG. 1;

FIG. 3 is a flowchart showing an operation of a receiving unit of the image data communication device of FIGS. 1 and 2;

FIG. 4 is a block diagram illustrating a receiving unit of the image data communication device according to the second embodiment of the present invention;

FIG. 5 is a block diagram showing a decoder constituting the receiving unit of FIG. 4;

FIG. 6 is a flowchart showing the operation of the receiving unit of the image data communication device shown in FIGS. 4 and 5;

FIG. 7 is a block diagram showing an encoder and a decoder constituting a receiving unit of an image data communication device according to a third embodiment of the present invention.

FIG. 8 is a block diagram showing a receiving unit of a conventional image data communication device.

FIG. 9 is a flowchart showing the operation of the receiving unit in FIG. 8;

[Explanation of symbols]

 Reference Signs List 1A, 1B receiver 2 line interface 3 CPU (central control unit) 4 image storage memory 5 encoder 6 discrete cosine transformer 7 quantizer 8 Huffman encoder 9 Q value controller 10, 10A decoder 11 Huffman Decoder 12 Inverse quantizer 13 Inverse discrete cosine transformer 14 Changeover switch N Communication network

Claims (6)

[Claims] 1. An image receiving apparatus comprising: an encoder for compressing and encoding received non-compressed image data; an image storage memory for storing the compressed and encoded image data; and a central control unit for controlling the whole. A data communication device, wherein the central control unit controls a Q value of the encoder according to a free space of the image storage memory, and controls an amount of image data stored in the image storage memory to the uncompressed image. An image data communication device, wherein the amount of data is reduced from the data amount. 2. A decoder for decoding received compressed image data, an encoder for compressing and encoding decompressed image data obtained by decoding said compressed image data by said decoder, and said compressor and decoder. An image data communication device having an image storage memory for storing encoded image data and a central control unit for controlling the whole in a receiving unit, wherein the central control unit is configured to perform the image processing according to a free space of the image storage memory. An image data communication device, wherein the Q value of an encoder is controlled so that the amount of image data stored in the image storage memory is smaller than the amount of compressed image data. 3. A decoder for dequantizing received compressed image data and outputting dequantized image data, an encoder for quantizing the dequantized image data, and compressing / encoding the compressed image data, and the compression / encoding. An image data communication device having a receiving unit having an image storage memory for storing the converted image data and a central control unit for controlling the whole, wherein the central control unit is configured to control the code in accordance with a free space of the image storage memory. An image data communication device for controlling the Q value of the imager to reduce the amount of image data stored in the image storage memory from the amount of compressed image data. 4. An image data processing method for compressing and encoding received non-compressed image data and storing the compressed and encoded image data in an image storage memory, wherein the Q value in the compression and encoding is An image data processing method, wherein the amount of image data stored in the image storage memory is controlled to be smaller than the amount of uncompressed image data by controlling according to the free space of the image storage memory. 5. A decoding device for decoding received compressed image data, compressing and encoding expanded image data obtained by decoding the compressed image data, and storing the compressed and encoded image data in an image storage memory. An image data processing method for storing, wherein a Q value in the compression / encoding is controlled according to a free space of the image storage memory, and an amount of image data to be stored in the image storage memory is controlled by the data of the compressed image data. An image data processing method, characterized in that the image data is reduced from the amount. 6. A dequantized received image data is dequantized to generate dequantized image data, the dequantized image data is quantized, compressed and encoded, and the compressed and encoded image data is stored in an image. A method of processing image data stored in a memory, wherein a Q value in the compression / encoding is controlled according to a free space of the image storage memory, and an amount of image data stored in the image storage memory is controlled by the compressed image data. An image data processing method characterized by reducing the data amount of the image data.