Method and apparatus for calculating the background color of an image
View Patent ↗A method, device and computer readable storage media for enhancing an image for optical character recognition by detecting the edges of the image to create an edge detected image, binarizing the edge detected image to create a binary edge image for processing, dilating the binary edge image to create a dilated binary edge image, taking the XOR difference between the binary edge image and the dilated binary edge image to obtain a text boundary, superimposing the text boundary on the image and determining the pixels of the image that are covered by the text boundary, calculating the average grayscale value of the pixels of the image that are covered by the text boundary, and setting background pixels of the image to the calculated average grayscale value of the pixels of the image that are covered by the text boundary. The method optionally includes the steps of performing edge filling and hole filling on the binary edge image to create an updated binary edge image and filling holes in the dilated binary edge image to create an updated dilated binary edge image, whereby the XOR difference is taken between the updated binary edge image and the updated dilated binary edge image. The image may be binarized for optimal results after the background images have been set to the calculated average grayscale value of the pixels that are covered by the text boundary.
1. A method of enhancing an image for optical character recognition, comprising:
detecting the edges of the image to create an edge detected image;
binarizing the edge detected image to create a binary edge image for processing;
dilating the binary edge image to create a dilated binary edge image;
taking the XOR difference between the binary edge image and the dilated binary edge image to obtain a text boundary;
superimposing the text boundary on the image and determining the pixels of the image that are covered by the text boundary;
calculating the average grayscale value of the pixels of the image that are covered by the text boundary; and
setting background pixels of the image to the calculated average grayscale value of the pixels of the image that are covered by the text boundary.
2. A method as in claim 1 , further comprising performing edge filling and hole filling on the binary edge image to create an updated binary edge image and filling holes in the dilated binary edge image to create an updated dilated binary edge image, whereby the XOR difference is taken between the updated binary edge image and the updated dilated binary edge image.
3. A method as in claim 1 , further comprising binarizing the image after the background images have been set to the calculated average grayscale value of the pixels of the image that are covered by the text boundary.
4. A computer readable memory device having instructions thereon that when processed by a processor cause the implementation of a method of enhancing an image for optical character recognition, the method comprising:
detecting the edges of the image to create an edge detected image;
binarizing the edge detected image to create a binary edge image for processing;
dilating the binary edge image to create a dilated binary edge image;
taking the XOR difference between the binary edge image and the dilated binary edge image to obtain a text boundary;
superimposing the text boundary on the image and determining the pixels of the image that are covered by the text boundary;
calculating the average grayscale value of the pixels of the image that are covered by the text boundary; and
setting background pixels of the image to the calculated average grayscale value of the pixels of the image that are covered by the text boundary.
5. The memory device as in claim 4 , further comprising instructions for performing edge filling and hole filling on the binary edge image to create an updated binary edge image and filling holes in the dilated binary edge image to create an updated dilated binary edge image, and for taking the XOR difference between the updated binary edge image and the updated dilated binary edge image.
6. A memory device as in claim 4 , further comprising instructions for binarizing the image after the background images have been set to the calculated average grayscale value of the pixels of the image that are covered by the text boundary.
7. A device for enhancing an image for optical character recognition, comprising:
a scanner that scans the image to obtain a grayscale image; and
a processor that processes the grayscale image by:
detecting the edges of the image to create an edge detected image;
binarizing the edge detected image to create a binary edge image for processing;
dilating the binary edge image to create a dilated binary edge image;
taking the XOR difference between the binary edge image and the dilated binary edge image to obtain a text boundary;
superimposing the text boundary on the image and determining the pixels of the image that are covered by the text boundary;
calculating the average grayscale value of the pixels of the image that are covered by the text boundary; and
setting background pixels of the image to the calculated average grayscale value of the pixels of the image that are covered by the text boundary.
8. A device as in claim 7 , wherein the processor further performs edge filling and hole filling on the binary edge image to create an updated binary edge image and fills holes in the dilated binary edge image to create an updated dilated binary edge image, whereby the XOR difference is taken between the updated binary edge image and the updated dilated binary edge image.
9. A device as in claim 7 , wherein the processor further binarizes the image after the background images have been set to the calculated average grayscale value of the pixels of the image that are covered by the text boundary.