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US 8,274,705 B2Granted
Multi-level surround error diffusion
AssigneeSharp Laboratories of America, Inc.
InventorChing-Wei Chang
Life of this patent
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Abstract
Machine-enabled methods of, and system, and processor readable media, embodiments for, tone quantization error diffusion comprising a first stage process and a second stage process. where pre-calibrated index tables may be applied by which quantized pixels may be expressed according to halftones.
Claims11
A method of diffusing tone quantization error of a digital image comprising:
- receiving a digital image having input pixel tone levels for one or more color channels according to i rows and j columns;
- for alternate rows of pixels of the digital image:
- quantizing an assigned pixel tone level of each pixel, or Si,j, per color channel, in series j based on an integer downsizing, wherein the assigned tone level, or Si,j, comprises an input tone value, or Pi,j, and, a partial tone quantization error, or Ni,j−1, from the last quantized pixel in row i, if present;
- and
- determining for each pixel in series j of the alternate rows of pixels, and per color channel, a total quantization error, or Di,j, based on the assigned pixel tone level of the pixel, or Si,j, and the quantized assigned pixel tone level of the pixel, or Qi,j, wherein the total quantization error, or Di,j,comprises a partial tone quantization error, or Ni,j, and a remainder tone quantization error, or Ei,j;
- and
- storing, per color channel, the remainder tone quantization error, or Ei,j;
- and
- for rows of pixels interposed between the alternate rows of pixels of the digital image:
- quantizing an assigned pixel tone level of each pixel, or Si,j, per color channel, in series j based on an integer downsizing, wherein the assigned tone level, or Si,j,comprises:
- (a) an input tone value, or Pi,j;
- (b) a partial tone quantization error, or Ni,j−1, from the last quantized pixel in row i, if present;
- and (c) a sum of a weighted remainder tone quantization errors of two or more of the nearest neighbor pixels of the alternate rows comprising the sum:
- w2*Ei−1,j+w5*Ei+1,j+w6*Ei+1,j+1 and, at least one of:
- (i) the sum:
- w1*Ei−1,j−1+w4*Ei−1,j−1 and (ii) the sum:
- w3*Ei−1,j+1+w6*Ei+1,j+1, wherein w1,w2, w3, w4, w5, and w6, are weighted apportionments given to a set of tone quantization error remainders;
- and
- determining, for each pixel in series j of the rows of pixels interposed between the alternate rows of pixels, and per color channel, a total quantization error, or Di,j , based on the assigned pixel tone level of the pixel, or Si,j, and the quantized assigned pixel tone level of the pixel, or Q i,j, wherein the total quantization error, or Di,j, comprises a partial tone quantization error, or Ni,j.
16 more elements
A system for producing image output comprising:
- a image tone quantization module configured to:
- input a digital image having input pixel tone levels for one or more color channels according to i rows and j columns;
- for alternate rows of pixels of the digital image:
- quantize an assigned pixel tone level of each pixel, or Si,j, per color channel, in series j based on an integer downsizing, wherein the assigned tone level, or Si,j, comprises an input tone value, or Pi,j, and, a partial tone quantization error, or Ni,j−1, from the last quantized pixel in row i, if present;
- and
- determine for each pixel in series j, and per color channel, a total quantization error, or Di,j, based on the assigned pixel tone level of the pixel, or Si,j, and the quantized assigned pixel tone level of the pixel, or Qi,j, wherein the total quantization error, or Di,j, comprises a partial tone quantization error, or Ni,j, and a remainder tone quantization error, or Ei,j;
- and
- store, per color channel, the remainder tone quantization error, or Ei,j;
- and
- for rows of pixels interposed between the alternate rows of pixels of the digital image:
- quantize an assigned pixel tone level of each pixel, or S i,j, per color channel, in series j based on an integer downsizing, wherein the assigned tone level, or S comprises:
- (a) an input tone value, or Pi,j;
- (b) a partial tone quantization error, or Ni,j−1, from the last quantized pixel in row i, if present;
- and (c) a sum of a weighted remainder tone quantization errors of two or more of the nearest neighbor pixels of the alternate rows comprising the sum:
- w2*Ei−1,j+w5*Ei+1,j+w6*Ei+1,j+1 and, at least one of:
- (i) the sum:
- w1*Ei−1,j−1+w4*Ei+1,j−1;
- and (ii) the sum:
- w3*Ei−1,j+1 +w6*Ei+1,j+1, wherein w1,w2, w3, w4, w5, and w6, are weighted apportionments given to a set of tone quantization error remainders;
- and
- determine, for each pixel in series j, and per color channel, a total quantization error, or Di,j, based on the assigned pixel tone level of the pixel, or Si,j, and the quantized assigned pixel tone level of the pixel, or Qi,j, wherein the total quantization error, or Di,j, comprises a partial tone quantization error, or Ni,j.
18 more elements
A processor readable non-transitory medium having processor executable instructions thereon which, when executed by a processor cause the processor to:
- input a digital image having input pixel tone levels for one or more color channels according to i rows and j columns;
- for alternate rows of pixels of the digital image:
- quantize an assigned pixel tone level of each pixel, or Si,j, per color channel, in series j based on an integer downsizing, wherein the assigned tone level, or S comprises an input tone value, or Pi,j, and, a partial tone quantization error, or Ni,j−1, from the last quantized pixel in row i, if present;
- and
- determine for each pixel in series j, and per color channel, a total quantization error, or Di,j, based on the assigned pixel tone level of the pixel, or S and the quantized assigned pixel tone level of the pixel, or Qi,j, wherein the total quantization error, or Di,j, comprises a partial tone quantization error, or Ni,j, and a remainder tone quantization error, or Ei,j;
- and
- store, per color channel, the remainder tone quantization error, or Ei,j;
- and
- for rows of pixels interposed between the alternate rows of pixels of the digital image:
- quantize an assigned pixel tone level of each pixel, or Si,j, per color channel, in series j based on an integer downsizing, wherein the assigned tone level, or S comprises:
- (a) an input tone value, or Pi,j;
- (b) a partial tone quantization error, or Ni,j−1, from the last quantized pixel in row i, if present;
- and (c) a sum of a weighted remainder tone quantization errors of two or more of the nearest neighbor pixels of the alternate rows comprising the sum:
- w2*Ei−1,j+w5*Ei+1,j+w6*Ei+1,j+1 and, at least one of:
- (i) the sum:
- w1*Ei−1,j−1+w4*Ei+1,j−1 and (ii) the sum:
- w3*Ei−1,j+1+w6*Ei−1,j+1;
- wherein w1,w2, w3, w4, w5, and w6, are weighted apportionments given to a set of tone quantization error remainders;
- and
- determine, for each pixel in series j, and per color channel, a total quantization error, or Di,j, based on the assigned pixel tone level of the pixel, or Si,j, and the quantized assigned pixel tone level of the pixel, or Qi,j, wherein the total quantization error, or Di,j, comprises a partial tone quantization error, or Ni,j.
17 more elements
Dependencies are inferred from the claim text.