Method and mechanism for processing image data

A machine-readable medium carrying one or more sequences of instructions for processing image data, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

• processing color image data to generate gray scale image data, wherein the gray scale data comprises a set of data values, wherein each data value of the set of data values identifies a gray scale value of a sequence of gray scale values;
• determining a first measure, wherein the first measure is a frequency distribution that indicates a frequency of occurrence of each gray scale value, of the sequence of gray scale values, identified by the set of data values;
• determining a second measure that indicates the uniformity of the first measure;
• determining a third measure that indicates how close the first measure corresponds to a second frequency distribution;
• and
• upon determining that the third measure exceeds a first threshold and the second measure exceeds a second threshold, classifying the color image data as a first type of image data.

An apparatus for processing image data, comprising:

• one or more processors;
• a machine-readable medium carrying one or more sequences of instructions, wherein execution of the one or more sequences of instructions by the one or more processors causes the one or more processors to perform the steps of:
• processing color image data to generate gray scale image data, wherein the gray scale image data comprises a set of data values, wherein each data value of the set of data values identifies a gray scale value of a sequence of gray scale values;
• determining a first measure, wherein the first measure is a frequency distribution that indicates a frequency of occurrence of each gray scale value, of the sequence of gray scale values, identified by the set of data values;
• determining a second measure that indicates the uniformity of the first measure;
• determining a third measure that indicates how close the first measure corresponds to a second frequency distribution;
• and
• upon determining that the third measure exceeds a first threshold and the second measure exceeds a second threshold, classifying the color image data as a first type of image data.