Image recording method for image data having image components of three channels and a transmission ratio component of one channel, apparatus and computer readable recording medium storing program
In the structure for image data having image components of three channels and a transmission ratio component of one channel, the image data structure includes an image area in which the image components of three channels are recorded in a compressed format, and a transmission ratio area which has the same data structure as that of the image area and in which a transmission ratio component and pseudo components of two channels having the same compression format as that of the image components are recorded.
1. An image recording method, using a computer, for recording image data having image components of three channels and a transmission ratio component of one channel, the image data recording method comprising:
using a computer to carry out the steps of:
recording the image components of three channels with a compressed format in an image area; and
recording a transmission ratio component and pseudo components of two channels having same compression format as the compression format of the image components in a transmission ratio area with same data structure as the data structure of the image area.
2. An image recording method according to claim 1 , wherein, in the transmission ratio recording step, the pseudo components having entropy of zero are subjected to a compressing processing same as a compressing processing of the transmission ratio component to output the pseudo components of two channels of the compression format to the transmission ratio area.
3. An image recording method according to claim 1 , wherein, in the transmission ratio recording step, the pseudo components are quantized with a quantization step width larger than a quantization step width for the transmission ratio component to output the pseudo components of two channels of the compression format to the transmission ratio area.
4. An image recording method according to claim 1 , wherein, in the transmission ratio recording step, Huffman code having entropy of zero is recorded in the transmission ratio area to record the pseudo components of two channels in the transmission ratio area.
5. An image recording method according to claim 1 , wherein a structure of each of the image area and the transmission ratio area is JPEG format of three channels.
6. An image recording method according to claim 1 , wherein the image components, the transmission ratio component and the pseudo components are recorded in a file.
7. An image recording apparatus for recording image data having image components of three channels and a transmission ratio component of one channel, the image data recording apparatus comprising:
an image recorder that records the image components of three channels with a compressed format in an image area; and
a transmission ratio recorder that records a transmission ratio component and pseudo components of two channels having same compression format as the compression format of the image components in a transmission ratio area with same data structure as the data structure of the image area.
8. A computer readable recording medium that stores an image recording program for recording image data having image components of three channels and a transmission ratio component of one channel, the image data recording program functioning a computer as:
an image recorder that records the image components of three channels with a compressed format in an image area; and
a transmission ratio recorder that records a transmission ratio component and pseudo components of two channels having same compression format as the compression format of the image components in a transmission ratio area with same data structure as a data structure of the image area.
9. The computer readable medium according to claim 8 , wherein a structure of each of the image area and the transmission ratio area is JPEG format of three channels.
10. The computer readable medium according to claim 8 , wherein entropy of the pseudo component is zero.
11. The computer readable medium according to claim 8 , wherein the image components, the transmission ratio component and the pseudo components are recorded in a file.
12. A method of reproducing compressed image data having an image area in which image components of three channels are recorded with a compressed format; and a transmission ratio area which has a same data structure as the data structure of the image area and in which a transmission ratio component and pseudo components of two channels having a same compressed format as the compressed format of the image components are recorded, the method comprising:
using a computer to carry out the steps of:
decoding the image area;
decoding the transmission ratio area; and
reproducing decoded image data including: the decoded image components of three channels in the decoded image area; and the decoded transmission ratio component of one channel obtained by neglecting the pseudo components of two channels in the decoded transmission ratio area.
13. The method according to claim 12 , wherein the image area and the transmission ratio area are decoded by the same processing method.
14. The method according to claim 12 , wherein a structure of each of the image area and the transmission ratio area is JPEG format of three channels.
15. The method according to claim 12 , wherein the image components, the transmission ratio component and the pseudo components are recorded in a file.
16. An image reproducing apparatus for reproducing compressed image data having an image area in which image components of three channels are recorded with a compressed format; and a transmission ratio area which has a same data structure as the data structure of the image area and in which a transmission ratio component and pseudo components of two channels having a same compressed format as the compressed format of the image components are recorded, the method comprising:
an image area decoder that decodes the image area;
a transmission ratio area decoder that decodes the transmission ratio area; and
an image reproducer that reproduces decoded image data including: the decoded image components of three channels in the image area decoded by the image area decoder; and the decoded transmission ratio component of one channel obtained by neglecting the pseudo components of two channels in the transmission ratio area decoded by the transmission ratio area decoder.
17. The apparatus according to claim 16 , wherein the image area and the transmission ratio area are decoded by the same processing method.
18. The apparatus according to claim 16 , wherein a structure of each of the image area and the transmission ratio area is JPEG format of three channels.
19. The apparatus according to claim 16 , wherein the image components, the transmission ratio component and the pseudo components are recorded in a file.