Method, device, mobile terminal and computer program product for providing variable compression of data files

• US 20070242893A1
• Filed: 04/18/2006
• Published: 10/18/2007
• Est. Priority Date: 04/18/2006
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Corporation
• Inventors: Gill, Christopher
• Granted Patent: US 7,639,883 B2
• Time in Patent Office: Days
• US Class Current: 382/239
• CPC Class Codes: H04N 19/126 Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
• CPC Class Codes: H04N 19/60 using transform coding

Abstract

A device for providing variable compression of data files includes a weighting module, a summing module, and a processing element. The weighting module is capable of assigning a weighting value to each coefficient of an array of j number of coefficients. Each weighting value defines a characteristic associated with each corresponding coefficient. The summing module is in communication with the weighting module and is capable of adding the magnitude of a weighted value of an i^th coefficient to the absolute sum of weighted values of all previous coefficients, i being a value from 1 to j. The processing element is in communication with the summing module and is capable of comparing the absolute sum of the weighted values of the i^th coefficient and the previous coefficients to a threshold. If the absolute sum of the weighted values of the i^th coefficient and the previous coefficients is greater than the threshold then each of the previous coefficients are replaced with a zero. If the absolute sum of the weighted values of the i^th coefficient and the previous coefficients is less than or equal to the threshold, then i is incremented by one for repeated summing at the summing module.

Claims

1. A method of providing variable compression of data files, the method comprising:

assigning a weighting value to each coefficient of an array of j number of quantized coefficients, each weighting value defining a characteristic associated with each corresponding coefficient;

adding a magnitude of a weighted value of an i^th coefficient to a magnitude of each weighted value of all previous coefficients, i being a value from 1 to j;

comparing an absolute sum of the weighted values of the i^th coefficient and the previous coefficients to a threshold;

replacing each of the previous coefficients with a zero if the absolute sum of the weighted values of the i^th coefficient and all previous coefficients is greater than the threshold; and

incrementing i by one and repeating the adding step if the absolute sum of the weighted values of the i^th coefficient and all previous coefficients is less than or equal to the threshold.

2. A method according to claim 1, further comprising receiving an indication of an amount of data yet to be processed.

3. A method according to claim 2, further comprising receiving an indication of a remaining amount of budget in order to achieve a target data file size.

4. A method according to claim 3, further comprising changing the threshold dynamically in order to compress a data file to the target data file size in response to the indication of the amount of data yet to be processed and the remaining amount of budget.

5. A method according to claim 3, further comprising changing the weighting values dynamically in order to compress a data file to the target data file size in response to the indication of the amount of data yet to be processed and the remaining amount of budget.

6. A method according to claim 1, wherein the adding step is performed in accordance with a predetermined sequence.

7. A method according to claim 1, further comprising forming a resultant linear sequence of coefficients from one of:

a modified sequence including zeros for the previous coefficients and unchanged values for remaining coefficients in response to the absolute sum of the weighted values of the i^th coefficient and the previous coefficients being greater than the threshold; and

a sequence formed from unchanged values from the array of j number of quantized coefficients if the absolute sum of the weighted values of the j^th coefficient and the previous coefficients is less than or equal to the threshold.

8. A method according to claim 7, further comprising encoding the resultant linear sequence of coefficients using a JPEG encoder.

9. A method according to claim 1, the adding step is performed in accordance with a sequence that is dynamically alterable.

10. A computer program product for providing variable compression of data files, the computer program product comprising at least one computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising:

a first executable portion for assigning a weighting value to each coefficient of an array of j number of quantized coefficients, each weighting value defining a characteristic associated with each corresponding coefficient;

a second executable portion for adding a magnitude of a weighted value of an i^th coefficient to a magnitude of each weighted value of all previous coefficients, i being a value from 1 to j;

a third executable portion for comparing an absolute sum of the weighted values of the i^th coefficient and the previous coefficients to a threshold;

a fourth executable portion for replacing each of the previous coefficients with a zero if the absolute sum of the weighted values of the i^th coefficient and all previous coefficients is greater than the threshold; and

a fifth executable portion for incrementing i by one and repeating the adding step if the absolute sum of the weighted values of the i^th coefficient and all previous coefficients is less than or equal to the threshold.

11. A computer program product according to claim 10, further comprising a sixth executable portion for receiving an indication of an amount of data yet to be processed.

12. A computer program product according to claim 11, further comprising a seventh executable portion for receiving an indication of a remaining amount of budget in order to achieve a target data file size.

13. A computer program product according to claim 12, further comprising an eighth executable portion for changing the threshold dynamically in order to compress a data file to the target data file size in response to the indication of the amount of data yet to be processed and the indication of the remaining amount of budget.

14. A computer program product according to claim 12, further comprising an eighth executable portion for changing the weighting values dynamically in order to compress a data file to the target data file size in response to the indication of the amount of data yet to be processed and the remaining amount of budget.

15. A device for providing variable compression of data files, the device comprising:

a weighting module capable of assigning a weighting value to each coefficient of an array of j number of quantized coefficients, each weighting value defining a characteristic associated with each corresponding coefficient;

a summing module in communication with the weighting module and capable of adding a magnitude of a weighted value of an i^th coefficient to a magnitude of each weighted value of all previous coefficients, i being a value from 1 to j; and

a processing element in communication with the summing module and capable of comparing an absolute sum of the weighted values of the i^th coefficient and the previous coefficients to a threshold,

wherein if the absolute sum of the weighted values of the i^th coefficient and the previous coefficients is greater than the threshold then each of the previous coefficients are replaced with a zero; and

wherein if the absolute sum of the weighted values of the i^th coefficient and the previous coefficients is less than or equal to the threshold, then i is incremented by one for repeated summing at the summing module.

16. A device according to claim 15, wherein the processing element is further capable of receiving an indication of an amount of data yet to be processed.

17. A device according to claim 16, wherein the processing element is further capable of receiving an indication of a remaining amount of budget in order to achieve a target data file size.

18. A device according to claim 17, wherein the processing element is further capable of changing the threshold dynamically in order to compress a data file to the target data file size in response to the indications of the amount of data yet to be processed and the remaining budget.

19. A device according to claim 17, wherein the processing element is further capable of changing the weighting values dynamically in order to compress a data file to the target data file size in response to the indications of the amount of data yet to be processed and the remaining budget.

20. A device according to claim 15, wherein the summing module adds coefficients in accordance with a predetermined sequence.

21. A device according to claim 15, wherein the summing module adds coefficients in accordance with a sequence that is dynamically alterable.

22. A device according to claim 15, wherein the processing element is further capable of forming a resultant linear sequence of coefficients from one of:

a modified sequence including zeros for the previous coefficients and unchanged values for remaining coefficients in response to the absolute sum of the weighted values of the i^th coefficient and the previous coefficients being greater than the threshold; and

a sequence formed from unchanged values from the array of j number of quantized coefficients if the absolute sum of the weighted values of the j^th coefficient and the previous coefficients is less than or equal to the threshold.

23. A device according to claim 22, further comprising a JPEG encoder that encodes the resultant linear sequence of coefficients.

24. A mobile terminal having a camera module for providing variable compression of data files, the mobile terminal comprising:

a weighting module capable of assigning a weighting value to each coefficient of an array of j number of quantized coefficients, each weighting value defining a characteristic associated with each corresponding coefficient;

a summing module in communication with the weighting module and capable of adding a magnitude of a weighted value of an i^th coefficient to a magnitude of each weighted value of all previous coefficients, i being a value from 1 to j; and

a processing element in communication with the summing module and capable of comparing an absolute sum of the weighted values of the i^th coefficient and the previous coefficients to a threshold,

wherein if the absolute sum of the weighted values of the i^th coefficient and the previous coefficients is greater than the threshold then each of the previous coefficients are replaced with a zero; and

wherein if the absolute sum of the weighted values of the i^th coefficient and the previous coefficients is less than or equal to the threshold, then i is incremented by one for repeated summing at the summing module.

25. A mobile terminal according to claim 24, wherein the processing element is further capable of receiving an indication of an amount of data yet to be processed.

26. A mobile terminal according to claim 25, wherein the processing element is further capable of receiving an indication of a remaining amount of budget in order to achieve a target data file size.

27. A mobile terminal according to claim 26, wherein the processing element is further capable of changing the threshold dynamically in order to compress a data file to the target data file size in response to the indications of the amount of data yet to be processed and the remaining budget.

28. A mobile terminal according to claim 26, wherein the processing element is further capable of changing the weighting values dynamically in order to compress a data file to the target data file size in response to the indications of the amount of data yet to be processed and the remaining budget.

29. A mobile terminal according to claim 24, wherein the summing module adds coefficients in accordance with a predetermined sequence.

30. A mobile terminal according to claim 24, wherein the summing module adds coefficients in accordance with a sequence that is dynamically alterable.

31. A mobile terminal according to claim 24, wherein the processing element is further capable of forming a resultant linear sequence of coefficients from one of:

a modified sequence including zeros for the previous coefficients and unchanged values for remaining coefficients in response to the absolute sum of the weighted values of the i^th coefficient and the previous coefficients being greater than the threshold; and

a sequence formed from unchanged values from the array of j number of quantized coefficients if the absolute sum of the weighted values of the j^th coefficient and the previous coefficients is less than or equal to the threshold.

32. A mobile terminal according to claim 31, further comprising a JPEG encoder that encodes the resultant linear sequence of coefficients.

33. A method of providing variable compression of data files, the method comprising:

receiving a data segment comprising a plurality of blocks having respective coefficients associated with each of the blocks;

assigning a weighting value to each of the coefficients based on frequency information associated with data in each of the blocks; and

setting one or more of the coefficients to zero based on an aggregation of weighted values,

wherein different numbers of coefficients are set to zero in one data segment than in another data segment.

34. A method according to claim 33, wherein the setting step comprises comparing the aggregation of the weighted values to a threshold and setting the one or more coefficients to zero in response to the aggregation reaching the threshold.