Methods and apparatuses for driving display systems
Methods and apparatus for image processing are provided. A method for image processing includes: (a) accessing, in a lookup table, a current pattern index for a current pixel based on a current pixel input value and a previous pattern index; (b) accessing, in a dither mask array, a threshold value for the current pixel based on a location of the current pixel; (c) comparing the current pattern index with the threshold value; (d) determining a current pixel output value for activation of the current pixel based on a result of the comparing; (e) storing the current pattern index to serve as the previous pattern index for a next image; and (f) repeating acts (a)-(e) for each pixel in the image.
1. A method for image processing comprising:
(a) accessing, in a lookup table, a current pattern index for a current pixel based on a current pixel input value and a previous pattern index;
(b) accessing, in a dither mask array, a threshold value for the current pixel based on a location of the current pixel;
(c) comparing the current pattern index with the threshold value;
(d) determining a current pixel output value for activation of the current pixel based on a result of the comparing;
(e) storing the current pattern index to serve as the previous pattern index for a next image; and
(f) repeating acts (a)-(e) for each pixel in an image to reduce differential blooming.
2. The method for image processing as defined in claim 1 , further comprising repeating acts (a)-(f) for a plurality of images.
3. The method for image processing as defined in claim 1 , wherein determining the current pixel output value comprises determining a first output value or a second output value.
4. The method for image processing as defined in claim 3 , wherein determining the current pixel output value comprises determining the first output value if the current pattern index is greater than the threshold value and otherwise determining the second output value.
5. The method for image processing as defined in claim 1 , wherein determining the current pixel output value comprises determining one of three or more pixel output values.
6. The method for image processing as defined in claim 1 , wherein storing the current pattern index comprises storing the current pattern index in a pattern index buffer.
7. The method for image processing as defined in claim 6 , wherein the pattern index buffer has a location for each pixel in the image.
8. The method for image processing as defined in claim 1 , wherein the dither mask array is addressed by the location of the current pixel mod k,l, where k and 1 are dimensions of the dither mask array.
9. The method for image processing as defined in claim 1 , wherein comparing the current pattern index comprises determining if the current pattern index is between a first threshold value and a second threshold value.
10. The method for image processing as defined in claim 1 , further comprising activating the current pixel of an electrophoretic display in accordance with the determined current pixel output value.
11. Apparatus for image processing comprising:
a memory device storing a lookup table configured to provide a current pattern index for a current pixel based on a current pixel input value and a previous pattern index;
a dither mask array configured to provide a threshold value based on a location of the current pixel;
a comparator circuit configured to compare the current pattern index with the threshold value and to provide a result indicative of a current pixel output value for activation of the current pixel; and
a pattern index buffer configured to store the current pattern index as the previous pattern index for each pixel of an image and to provide the previous pattern index for the current pixel based on the location of the current pixel to reduce differential blooming.
12. The apparatus for image processing as defined in claim 11 , further comprising a display control unit configured to control the apparatus to provide the result indicative of the current pixel output value for each pixel in an image.
13. The apparatus for image processing as defined in claim 12 , wherein the display control unit is configured to control the apparatus to provide the result indicative of the current pixel output value for a plurality of images.
14. The apparatus for image processing as defined in claim 11 , wherein the comparator circuit is configured to provide the result indicative of a first output value or a second output value.
15. The apparatus for image processing as defined in claim 14 , wherein the comparator circuit is configured to provide the first output value if the current pattern index is greater than the threshold value and otherwise to provide the second output value.
16. The apparatus for image processing as defined in claim 11 , wherein the comparator circuit is configured to provide the result indicative of one of three or more pixel output values.
17. The apparatus for image processing as defined in claim 11 , wherein the pattern index buffer has a location for each pixel in the image.
18. The apparatus for image processing as defined in claim 11 , wherein the dither mask array is addressed by the location of the current pixel mod k, 1 , where k and 1 are dimensions of the dither mask array.
19. The apparatus for image processing as defined in claim 11 , wherein the comparator circuit is configured to determine if the current pattern index is between a first threshold value and a second threshold value.
20. The apparatus for image processing as defined in claim 11 , wherein the comparator circuit is configured to provide the result indicative of the current pixel output value of an electrophoretic display.