IMAGE BINARIZATION FOR OPTICAL CHARACTER RECOGNITION

摘要

Systems and methods convert to binary an input image having pixels defining text and background. Thresholds are determined by which pixels in the input image and a corresponding blurred image will be defined as either binary black or binary white. Thresholds derive from grouped together neighboring pixels having pixels separated out that correspond to the background. For pixels of the input image defined as binary black and having corresponding pixels in the blurred image defined as binary black relative to their thresholds, those are set to black in the binary image, else they are set white. Techniques for devising thresholds, blurring images, grouping together pixels, statistical analysis, etc., typify the embodiments.

主权项

1. A method of converting to a binary image an input image having pluralities of pixels defining text and background each with an intensity value defined on a scale of multiple intensity values, comprising:
blurring the input image so that the pixels of the input image have corresponding blurred pluralities of pixels each with blurred intensity values defined on said scale of multiple intensity values; comparing the intensity value of a pixel under consideration of the input image to a first threshold value defined on the scale of multiple intensity values, the first threshold value being devised from pixels neighboring said pixel under consideration; and comparing the blurred intensity value of a blurred version of the pixel under consideration of the input image to a second threshold value defined on the scale of multiple intensity values, the second threshold value being devised from pixels neighboring the blurred version of the pixel under consideration, wherein if both the intensity value of the pixel under consideration is less than or equal to the first threshold value and the blurred intensity value is less than or equal to the second threshold value, setting the intensity value of the pixel under consideration to black in the binary image, else setting the intensity value of the pixel under consideration to white in the binary image.