Localized signal data preservation within signal bandwidth
View Patent ↗A system and method for reducing the noise induced in a particular section or level of a signal bandwidth. The section is isolated from the rest of the signal data, by rescaling this data to produce a buffer section adjacent the section with little or no data in it. The signal is then transmitted to the output device where all data is the buffer section is considered to be the result of noise, and is mapped back to the predetermined level. The signal data is inversely rescaled to move data back into the buffer section. In this way, more of the data that was input at the predetermined level, will also be at the predetermined level afterwards, thereby correcting noise induced in that level by noise inducing transmission techniques such as JPEG compression.
1. A method of processing signal data, the signal data resulting from lossy compression and decompression of an input signal, the input signal having at least one known data value, the method comprising:
for each known data value, mapping data values in a buffer section adjacent to the known data value to the known data value; and,
rescaling data values other than the known data values to move data values back into the buffer section.
2. A method according to claim 1 wherein the input signal is image data for a color plane of an image.
3. A method according to claim 2 wherein the signal data is pixel intensity values for the color plane quantized into a number of discrete intensity levels.
4. A method according to claim 3 wherein the at least one known data value includes the intensity level corresponding to zero color intensity.
5. A method according to claim 4 wherein the at least one known data value includes a maximum intensity level.
6. A method according to claim 1 wherein the signal data is image data and the method further comprising the step of converting the image data from a first color space to a second color space, wherein the rescaling of the data values is performed simultaneously with the color space conversion.
7. A method according to claim 6 wherein the second color space is a printer color space.
8. A method according to claim 6 wherein the step of rescaling the image data back into the buffer section is performed via a dither matrix by adjusting the threshold values in the dither matrix.
9. A method according to claim 1 wherein the signal data is image data in a YCC-style color space, and the at least one known data value is an intermediate data value.
10. A method according to claim 1 wherein the buffer section is approximately 6% of the bandwidth.