Controlled moving window adaptive histogram equalization
View Patent ↗Methods and systems of processing an image to reduce artifacts caused by image processing are disclosed. One embodiment includes applying a controlled, adaptive histogram equalization technique to improve the quality of an image. The technique may include classifying an image. The embodiments may use a concentration ratio of an image or portions thereof. Another embodiment may include a system for applying an adaptive histogram equalization technique.
1. A moving-window, histogram equalization method of processing images, the method comprising:
breaking the image into a plurality of tiles; and
processing each of the plurality of tiles with a processor by:
obtaining a control parameter; wherein obtaining the control parameter includes obtaining a first control parameter and processing the first control parameter and the concentration ratio to obtain a second control parameter;
determining a histogram for one of the plurality of tiles;
determining a concentration ratio for the one of the plurality of tiles;
determining an area of the image that includes the one of the plurality of tiles and information outside the one of the plurality of tiles;
creating a first output by performing a histogram equalization on the area;
creating a second output based on the control parameter and the first output; and
using the second output to process the one of the plurality of tiles.
2. A method as claimed in claim 1 , wherein creating the first output includes creating a first look-up table and creating the second output includes creating a second look-up table.
3. A method as claimed in claim 1 , wherein the area includes the one of the plurality of tiles and one or more portions of other tiles in the plurality of tiles.
4. A method as claimed in claim 1 , wherein obtaining a first control parameter includes obtaining a control parameter from a user.
5. A method as claimed in claim 1 , wherein determining a concentration ratio for the one of the plurality of tiles includes scaling a concentration ratio value.
6. A method as claimed in claim 1 , wherein processing the first control parameter and the concentration ratio to obtain a second control parameter includes determining a mathematical root of the group of the first control parameter, the concentration ratio, or both.
7. A method as claimed in claim 1 , wherein processing the first control parameter and the concentration ratio to obtain a second control parameter includes multiplying one of the group of the first control parameter, the concentration ratio, or both by a number.
8. A method as claimed in claim 1 , wherein processing the first control parameter and the concentration ratio to obtain a second control parameter includes combining the first control parameter and the concentration ratio.
9. A system for processing images using a moving-window, histogram equalization technique, the system comprising:
a processor configured to break an image into a plurality of tiles and process each of the plurality of tiles by:
obtaining a first control parameter;
determining a histogram for one of the plurality of tiles;
determining a concentration ratio for the one of the plurality of tiles;
processing the first control parameter and the concentration ratio to obtain a second control parameter, wherein processing the first control parameter and the concentration ratio to obtain a second control parameter includes determining a mathematical root of the group of the first control parameter, the concentration ratio, or both;
determining an area of the image that includes the one of the plurality of tiles and information outside the one of the plurality of tiles;
creating a first set of values by performing a histogram equalization on the area;
creating a second set of values based on the second control parameter and the first set of values; and
using a second set of values to process the one of the plurality of tiles.
10. A system as claimed in claim 9 , wherein creating the first set of values includes creating a first look-up table and creating the second output includes creating a second look-up table.
11. A system as claimed in claim 9 , wherein the area includes the one of the plurality of tiles and one or more portions of other tiles in the plurality of tiles.
12. A system as claimed in claim 9 , wherein determining a concentration ratio for the one of the plurality of tiles includes scaling a concentration ratio value.
13. A system for processing images using a moving-window, histogram equalization technique, the system comprising:
a processor configured to break an image into a plurality of tiles and process each of the plurality of tiles by:
obtaining a first control parameter;
determining a histogram for one of the plurality of tiles;
determining a concentration ratio for the one of the plurality of tiles;
processing the first control parameter and the concentration ratio to obtain a second control parameter, wherein processing the first control parameter and the concentration ratio to obtain a second control parameter includes multiplying one of the group of the first control parameter, the concentration ratio, or both by a number;
determining an area of the image that includes the one of the plurality of tiles and information outside the one of the plurality of tiles;
creating a first set of values by performing a histogram equalization on the area;
creating a second set of values based on the second control parameter and the first set of values; and
using a second set of values to process the one of the plurality of tiles.
14. A system for processing images using a moving-window, histogram equalization technique, the system comprising:
a processor configured to break an image into a plurality of tiles and process each of the plurality of tiles by:
obtaining a first control parameter;
determining a histogram for one of the plurality of tiles;
determining a concentration ratio for the one of the plurality of tiles;
processing the first control parameter and the concentration ratio to obtain a second control parameter, wherein processing the first control parameter and the concentration ratio to obtain a second control parameter includes combining the first control parameter and the concentration ratio;
determining an area of the image that includes the one of the plurality of tiles and information outside the one of the plurality of tiles;
creating a first set of values by performing a histogram equalization on the area;
creating a second set of values based on the second control parameter and the first set of values; and
using a second set of values to process the one of the plurality of tiles.
15. A system as claimed in claim 13 , wherein creating the first set of values includes creating a first look-up table and creating the second output includes creating a second look-up table.
16. A system as claimed in claim 13 , wherein the area includes the one of the plurality of tiles and one or more portions of other tiles in the plurality of tiles.
17. A system as claimed in claim 13 , wherein determining a concentration ratio for the one of the plurality of tiles includes scaling a concentration ratio value.
18. A system as claimed in claim 14 , wherein creating the first set of values includes creating a first look-up table and creating the second output includes creating a second look-up table.
19. A system as claimed in claim 14 , wherein the area includes the one of the plurality of tiles and one or more portions of other tiles in the plurality of tiles.
20. A system as claimed in claim 14 , wherein determining a concentration ratio for the one of the plurality of tiles includes scaling a concentration ratio value.