Text enhancement of a textual image undergoing optical character recognition

A method for enhancing a textual image for undergoing optical character recognition, comprising:

• receiving an image that includes native lines of text;
• determining a background line profile that represents an average background intensity along the native lines in the image;
• determining a foreground line profile that represents an average background intensity along the native lines in the image;
• estimating an average or median stroke width of connected components representing text in the image;
• enhancing text quality if the average or median stroke width is less than a threshold value, the enhancing comprising:
• assigning pixels in the image having an intensity less than a selected parameter to a foreground portion of the image, wherein the selected parameter is determined at least in part from the background line profile and the foreground line profile;
• assigning pixels in the image having an intensity greater than the background line profile to the background portion of the image;
• and
• assigning selected pixels having an intensity between the selected parameter and the background line profile to base connected components of the native lines represented in edge space.

A system comprising a processor and storage, wherein the system enhances a textual image undergoing optical character recognition, comprising:

• an input component stored in the storage and executed by the processor that receives an input image having native lines of text;
• a background and foreground line profiling stored in the storage and executed by the processor component that determines background and foreground line profiles which respectively represent average background and foreground intensities in the image;
• an image quality detection component stored in the storage and executed by the processor that determines, based on an average or median stroke width and on variation in the background and foreground intensities, if a quality of the image satisfies a threshold value;
• a thresholding component stored in the storage and executed by the processor that assigns pixels to either a background or foreground portion of the image based on the background and foreground line profiles;
• and
• a stroke enhancement component stored in the storage and executed by the processor that enhances strokes of connected components representing text in the image if the image quality detection component determines that the quality of the image satisfies the threshold value.