Image processing based on automatic image-type detection

A method comprising:

• receiving an image into a computerized device;
• automatically dividing said image into image blocks, using said computerized device;
• automatically determining a block average by determining an average pixel value for each of said image blocks, using said computerized device;
• automatically determining a squared error for each pixel within each of said image blocks by calculating a squared difference between a pixel value and said block average for each said pixel in each of said image blocks, using said computerized device;
• automatically determining a sum of squared errors value for each of said image blocks by summing, for each of said image blocks, said squared error for all pixels within each of said image blocks, using said computerized device;
• automatically determining whether each of said image blocks comprises a white background block of said image by determining if said block average for each of said image blocks exceeds a white background threshold, using said computerized device;
• automatically removing ones of said image blocks determined to be said white background block to produce valid image blocks of said image, using said computerized device;
• automatically determining a number of high-variation blocks within said valid image blocks by counting ones of said valid image blocks that have said sum of squared errors value exceeding a block variation threshold, using said computerized device;
• automatically determining a page variance measure by dividing said number of high-variation blocks by a total number of said valid image blocks, using said computerized device;
• automatically classifying said image as comprising a halftone and text image based on said page variance measure exceeding a halftone threshold, using said computerized device;
• automatically determining a text index by counting a number of said valid image blocks that have said sum of squared errors value exceeding a text threshold, using said computerized device;
• automatically classifying said image as comprising a continuous tone image based on said page variance measure not exceeding said halftone threshold and said text index being below a text index threshold, using said computerized device;
• automatically classifying said image as comprising a continuous tone and text image based on said page variance measure not exceeding said halftone threshold and said text index not being below said text index threshold, using said computerized device;
• and
• automatically selecting an image processing mode based on said image being one of said halftone and text image, said continuous tone and text image, and said continuous tone image.

A method comprising:

• receiving an image into a computerized device;
• automatically dividing said image into image blocks, using said computerized device;
• automatically determining a block average by determining an average pixel value for each of said image blocks, using said computerized device;
• automatically determining a squared error for each pixel within each of said image blocks by calculating a squared difference between a pixel value and said block average for each said pixel in each of said image blocks, using said computerized device;
• automatically determining a sum of squared errors value for each of said image blocks by summing, for each of said image blocks, said squared error for all pixels within each of said image blocks, using said computerized device;
• automatically determining whether each of said image blocks comprises a white background block of said image by determining if said block average for each of said image blocks exceeds a white background threshold, using said computerized device;
• automatically removing ones of said image blocks determined to be said white background block to produce valid image blocks of said image, using said computerized device;
• automatically determining a number of high-variation blocks within said valid image blocks by counting ones of said valid image blocks that have said sum of squared errors value exceeding a block variation threshold, using said computerized device;
• automatically determining a page variance measure by dividing said number of high-variation blocks by a total number of said valid image blocks, using said computerized device;
• automatically classifying said image as comprising a halftone and text image based on said page variance measure exceeding a halftone threshold, using said computerized device;
• automatically determining a text index by counting a number of said valid image blocks that have said sum of squared errors value exceeding a text threshold, using said computerized device;
• automatically classifying said image as comprising a continuous tone image based on said page variance measure not exceeding said halftone threshold and said text index being below a text index threshold, using said computerized device;
• automatically classifying said image as comprising a continuous tone and text image based on said page variance measure not exceeding said halftone threshold and said text index not being below said text index threshold, using said computerized device;
• automatically selecting a tile-based parallel error diffusion image processing mode based on said image being said halftone and text image;
• automatically selecting a sequential error diffusion image processing mode based on said image being said continuous tone and text image;
• and
• automatically selecting a clustered dot halftone image processing mode based on said image being said continuous tone image.

An image processing device comprising:

• an input and output device receiving an image;
• and
• a processor operatively connected to said input and output device, said processor:
• automatically dividing said image into image blocks,
• automatically determining a block average by determining an average pixel value for each of said image blocks,
• automatically determining a squared error for each pixel within each of said image blocks by calculating a squared difference between a pixel value and said block average for each said pixel in each of said image blocks,
• automatically determining a sum of squared errors value for each of said image blocks,
• automatically removing ones of said image blocks determined to a white background block to produce valid image blocks of said image,
• automatically determining a number of high-variation blocks within said valid image blocks by counting ones of said valid image blocks that have said sum of squared errors value exceeding a block variation threshold,
• automatically determining a page variance measure by dividing said number of high-variation blocks by a total number of said valid image blocks,
• automatically classifying said image as comprising a halftone and text image based on said page variance measure exceeding a halftone threshold,
• automatically determining a text index by counting a number of said valid image blocks that have said sum of squared errors value exceeding a text threshold,
• automatically classifying said image as comprising a continuous tone image based on said page variance measure not exceeding said halftone threshold and said text index being below a text index threshold,
• automatically classifying said image as comprising a continuous tone and text image based on said page variance measure not exceeding said halftone threshold and said text index not being below said text index threshold, and
• automatically selecting an image processing mode based on said image being one of said halftone and text image, said continuous tone and text image, and said continuous tone image.