Connected component analysis with multi-thresholding to segment halftones

A method comprising:

• receiving an input image into a computerized device;
• converting said input image into a grayscale image using said computerized device;
• assigning blocks to areas of said grayscale image using said computerized device;
• calculating at least two different gray tone variation threshold measures for each of said blocks based on dynamic maximum and minimum gray tone intensity values and white background values within each of said blocks using said computerized device;
• creating different binary images by applying said different gray tone variation threshold measures to each of said blocks of said grayscale image using said computerized device;
• identifying connected components of a first binary image of said binary images using said computerized device;
• comparing pixels of each of said connected components of said first binary image with corresponding pixels of a second binary image of said binary images to identify pixel differences comprising white pixel count differences and white-black pixel transition differences using said computerized device;
• and
• identifying halftone areas within said input image based on said pixel differences exceeding limits using said computerized device.

An image processing apparatus comprising:

• an input/output device receiving an input image;
• and
• a processor operatively connected to said input/output device,
• said processor creating different binary images by applying different threshold measures to said input image,
• said processor identifying components of a first binary image of said binary images,
• said processor comparing pixels of each of said components of said first binary image with corresponding pixels of a second binary image of said binary images to identify pixel differences comprising white pixel count differences and white-black pixel transition differences,
• said processor identifying halftone areas within said input image based on said pixel differences exceeding a limit, and
• said input/output device outputting an identification of said halftone areas.

A printing device comprising:

• an input/output device receiving an input image;
• a processor operatively connected to said input/output device;
• and
• a marking engine operatively connected to said processor,
• said processor creating different binary images by applying different threshold measures to said input image,
• said processor identifying components of a first binary image of said binary images,
• said processor comparing pixels of each of said components of said first binary image with corresponding pixels of a second binary image of said binary images to identify pixel differences comprising white pixel count differences and white-black pixel transition differences,
• said processor identifying halftone areas within said input image based on said pixel differences exceeding a limit, and
• said processor treating said halftone area differently relative to other areas of said input image when printing said input image using said marking engine.