US 2010/0061629 A1 · Method and Apparatus for Binarization Threshold Calculation

Abstract

A method, computing device, and associated computer readable storage media containing instructions for binarizing a grayscale image by manually determining a first threshold that yields optimal binarization values to one or more images in a set of images, calculating the histograms of each of the images determined using the first threshold, calculating a set of statistical parameters such as the mean, standard deviation and variance of each histogram, determining a second threshold as a function of the set of statistical parameters, and comparing each pixel of the grayscale image to the second threshold. The second threshold T may be a function of the mean m, standard deviation s and variance v and is calculated by fitting a third degree polynomial curve T=a0+a1m+a2s+a3v, where the coefficients A=[a0 a1 a2 a3]T are found using a minimum mean square error algorithm. Grayscale values above the second threshold are assigned a first binarization value and grayscale values below the second threshold are assigned a second binarization value.

Claims33

Dependent claims

A method of binarizing a grayscale image, comprising:

determining a first threshold that yields optimal binarization values to one or more images in a set of images;
calculating the histograms of each of said one or more images determined using the first threshold;
calculating a set of statistics of each said histogram;
determining a second threshold as a function of said set of statistics;
and
comparing each pixel of said grayscale image to said second threshold, whereby grayscale values above said second threshold are assigned a first binarization value and grayscale values below said second threshold are assigned a second binarization value.

3 more elements

A computer readable storage medium having instructions stored thereon that when processed by a processor causes the implementation of a method of binarizing a grayscale image, said method comprising:

determining a first threshold that yields optimal binarization values to one or more images in a set of images;
calculating the histograms of each of said one or more images determined using the first threshold;
calculating a set of statistics each said histogram;
determining a second threshold as a function of said set of statistics;
and
comparing each pixel of said grayscale image to said second threshold, whereby grayscale values above said second threshold are assigned a first binarization value and grayscale values below said second threshold are assigned a second binarization value.

3 more elements

A device for binarizing a grayscale image, comprising:

a scanner for scanning an image to form said grayscale image;
and
a processor that processes said grayscale image by:
determining a first threshold that yields optimal binarization values to said grayscale image;
calculating the histograms of each grayscale image determined using the first threshold;
calculating a set of statistics of each said histogram;
determining a second threshold as a function of said set of statistics;
and
comparing each pixel of said grayscale image to said second threshold, whereby grayscale values above said second threshold are assigned a first binarization value and grayscale values below said second threshold are assigned a second binarization value.

6 more elements

Dependencies are inferred from the claim text.

Method and Apparatus for Binarization Threshold Calculation

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Method and Apparatus for Binarization Threshold Calculation

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Abstract

Claims33