Code processing device, code processing method, program, and recording medium

• US 20060152391A1
• Filed: 01/11/2006
• Published: 07/13/2006
• Est. Priority Date: 01/11/2005
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Sakuyama, Hiroyuki
• Granted Patent: US 7,697,767 B2
• Time in Patent Office: Days
• US Class Current: 341/51
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/63 using sub-band based transform, e.g. wavelets

Abstract

In a code processing device, a rank assignment unit assigns ranks to sets of partial codes of original codes respectively, wherein, when the sets have different quality levels, a high rank is assigned to a set of partial codes having a low quality level, and when the sets have a same quality level and different resolution levels, a high rank is assigned to a set of partial codes having a low resolution level. A partial code selecting unit selecting sets of partial codes that have a quality specified by a specified quality value and are included in output codes, in order of the assigned ranks. A code forming unit forms the output codes in which the sets of selected partial codes are included.

Claims

1. A code processing device which generates, from original codes having sets of partial codes with quality attributes and resolution attributes, output codes having a quality according to a specified quality value, the code processing device comprising:

a rank assignment unit to assign ranks to the sets of partial codes respectively, wherein, when the sets of partial codes have different quality levels, a high rank is assigned to a set of partial codes having a low quality level, and when the sets of partial codes have a same quality level and different resolution levels, a high rank is assigned to a set of partial codes having a low resolution level;

a partial code selecting unit to select sets of partial codes from among the original codes, which have the quality according to the specified quality value and are included in the output codes, in order of the ranks assigned by the rank assignment unit; and

a code forming unit to form the output codes in which the sets of partial codes selected by the partial code selecting unit are included.

3. The code processing device according to claim 1 wherein the rank assignment unit is operable to incorporate, when the original codes comprise a plurality of components, a visual frequency characteristic of each component in the resolution attributes by which the ranks are assigned to the partial codes.

4. The code processing device according to claim 3 wherein the rank assignment unit is operable to change, according to a compression ratio or a quantization error of the original codes, the visual frequency characteristic of each component which is incorporated in the resolution attributes by which the ranks are assigned to the partial codes.

5. The code processing device according to claim 3 wherein the rank assignment unit is operable to change, according to the specified quality value, the visual frequency characteristic of each component which is incorporated in the resolution attributes by which the ranks are assigned to the partial codes.

6. The code processing device according to claim 3 wherein the rank assignment unit is operable to change, according to both the specified quality value and a compression ratio or a quantization error of the original codes, the visual frequency characteristic of each component which is incorporated in the resolution attributes by which the ranks are assigned to the partial codes.

13. The code processing device of claim 1 further comprising a communication unit which receives the specified quality value from an external device, and transmits the output codes formed by the code forming unit to the external device.

2. A code processing device which generates, from original codes having sets of partial codes with quality attributes and resolution attributes, output codes having a quality according to a specified quality value, the code processing device comprising:

a rank assignment unit to assign ranks to sets of partial codes, among the sets of partial codes of the original codes, which have a specific quality level determined according to the specified quality value, respectively, wherein a high rank is assigned to a set of partial codes having a low resolution level and a next high quality level that is higher than the specific quality level;

a partial code selecting unit to select sets of partial codes from the original codes in order of the ranks assigned by the rank assignment unit, the selected sets of partial codes including all sets of partial codes having a quality level lower than the specific quality level, and sets of partial codes having the next high quality level; and

a code forming unit to form the output codes in which the sets of partial codes selected by the partial code selecting unit are included.

7. A code processing device which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing device comprising:

a rank assignment unit to assign ranks to packets of respective layers among the original codes in order from a highest layer to a lowest layer based on a visual weight selected according to a compression ratio or a quantization error of the original codes;

a packet selecting unit to select packets from the original codes, which have the quality according to the specified quality value and are included in the output codes, in order of the ranks assigned by the rank assignment unit; and

a code forming unit to form the output codes in which the packets selected by the packet selecting unit are included.

8. A code processing device which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing device comprising:

a rank assignment unit to assign ranks to packets of respective layers among the original codes in order from a highest layer to a lowest layer based on a visual weight selected according to the specified quality value;

a packet selecting unit to select packets from the original codes, which have the quality according to the specified quality value and are included in the output codes, in order of the ranks assigned by the rank assignment unit; and

a code forming unit to form the output codes in which the packets selected by the packet selecting unit are included.

9. A code processing device which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing device comprising:

a rank assignment unit to assign ranks to packets of respective layers among the original codes in order from a highest layer to a lowest layer based on a visual weight selected according to both the specified quality value and a compression ratio or a quantization error of the original codes;

a packet selecting unit to select packets from the original codes, which have the quality according to the specified quality value and are included in the output codes, in order of the ranks assigned by the rank assignment unit; and

a code forming unit to form the output codes in which the packets selected by the packet selecting unit are included.

10. A code processing device which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing device comprising:

a rank assignment unit to assign ranks to packets having a next high quality level that is higher than a specific quality level determined according to the specified quality value, based on a visual weight selected according to a compression ratio or a quantization error of the original codes;

a packet selecting unit to select packets from the original codes in order of the ranks assigned by the rank assignment unit, the selected packets including all packets having a quality level lower than the specific quality level and the packets having the next high quality level; and

a code forming unit to form the output codes in which the packets selected by the packet selecting unit are included.

11. A code processing device which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing device comprising:

a rank assignment unit to assign ranks to packets having a next high quality level that is higher than a specific quality level determined according to the specified quality value, based on a visual weight selected according to the specified quality value;

a packet selecting unit to select packets from the original codes in order of the ranks assigned by the rank assignment unit, the selected packets including all packets having a quality level lower than the specific quality level and the packets having the next high quality level; and

a code forming unit to form the output codes in which the packets selected by the packet selecting unit are included.

12. A code processing device which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing device comprising:

a rank assignment unit to assign ranks to packets having a next high quality level that is higher than a specific quality level determined according to the specified quality value, based on a visual weight selected according to both the specified quality value and a compression ratio or a quantization error of the original codes;

a packet selecting unit to select packets from the original codes in order of the ranks assigned by the rank assignment unit, the selected packets including all packets having a quality level lower than the specific quality level and the packets having the next high quality level; and

a code forming unit to form the output codes in which the packets selected by the packet selecting unit are included.

14. A code processing method which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing method comprising:

selecting a visual weight according to a compression ratio or a quantization error of the original codes;

assigning ranks to packets of respective layers among the original codes in order from a highest layer to a lowest layer based on the selected visual weight;

selecting packets from the original codes, which have a quality as indicated by a specified quality value and are included in the output codes, in order of the assigned ranks; and

forming the output codes in which the selected packets are included.

15. A code processing method which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing method comprising:

selecting a visual weight according to the specified quality value;

assigning ranks to packets of respective layers among the original codes in order from a highest layer to a lowest layer based on the selected visual weight;

selecting packets from the original codes, which have a quality as indicated by a specified quality value and are included in the output codes, in order of the assigned rank; and

forming the output codes in which the selected packets are included.

16. A code processing method which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing method comprising:

selecting a visual weight according to both the specified quality value and a compression ratio or a quantization error of the original codes;

assigning ranks to packets of respective layers among the original codes in order from a highest layer to a lowest layer based on the selected visual weight;

selecting packets from the original codes, which have a quality as indicated by a specified quality value and are included in the output codes, in order of the assigned ranks; and

forming the output codes in which the selected packets are included.

17. A code processing method which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing method comprising:

selecting a visual weight according to a compression ratio or a quantization error of the original codes;

assigning ranks to packets having a next high quality level that is higher than a specific quality level determined according to the specified quality value, based on the selected visual weight;

selecting packets from the original codes in order of the assigned ranks, the selected packets including all packets having a quality level lower than the specific quality level and the packets having the next high quality level; and

forming the output codes in which the selected packets are included.

18. A code processing method which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing method comprising:

selecting a visual weight according to the specified quality value;

assigning ranks to packets having a next high quality level that is higher than a specific quality level determined according to the specified quality value, based on the selected visual weight;

selecting packets from the original codes in order of the assigned ranks, the selected packets including all packets having a quality level lower than the specific quality level and the packets having the next high quality level; and

forming the output codes in which the selected packets are included.

19. A code processing method which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing method comprising:

selecting a visual weight according to both the specified quality value and a compression ratio or a quantization error of the original codes;

assigning ranks to packets having a next high quality level that is higher than a specific quality level determined according to the specified quality value, based on the selected visual weight;

selecting packets from the original codes in order of the assigned ranks, the selected packets including all packets having a quality level lower than the specific quality level and the packets having the next high quality level; and

forming the output codes in which the selected packets are included.

20. A computer program product embodied therein for causing a computer to execute a code processing method which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing method comprising:

selecting a visual weight according to a compression ratio or a quantization error of the original codes;

assigning ranks to packets of respective layers among the original codes in order from a highest layer to a lowest layer based on the selected visual weight;

selecting packets from the original codes, which have a quality as indicated by a specified quality value and are included in the output codes, in order of the assigned ranks; and

forming the output codes in which the selected packets are included.

21. A computer-readable recording medium embodied therein for causing a computer to execute a code processing method which generates, from original codes of JPEG2000 having a plurality of components, output codes having a quality according to a specified quality value, the code processing method comprising:

selecting a visual weight according to a compression ratio or a quantization error of the original codes;

assigning ranks to packets of respective layers among the original codes in order from a highest layer to a lowest layer based on the selected visual weight;

selecting packets from the original codes, which have a quality indicated by a specified quality value and are included in the output codes, in order of the assigned ranks and

forming the output codes in which the selected packets are included.