Low resolution raster images

A method of enhancing the reproduction of black and white digitally defined images represented by a plurality of signals representing the image pixels comprising the steps of

• isolating a predetermined number of the pixel signals,
• forming a pattern from the isolated pixel signals including a center pixel and surrounding pixels,
• generating an identifier uniquely describing the isolated pixel pattern,
• expanding the central pixel in accordance with the particular identifier.

Apparatus for enhancement of an image represented by a plurality of pixels including

• a register for receiving digital representations of the pixels of the image, the representations including at least portions of successive scan lines of the image,
• means for storing a portion of each of the pixel representations of the successive scan lines to form a composite pixel pattern,
• a source of standard pixel formats,
• means for comparing the composite pixel patterns with standard formats,
• logic means responsive to the comparison for producing signals representative of the comparison, and
• a decoder responsive to the signals representing the comparison to produce an enhanced pixel pattern for each pixel of the image.

Apparatus for enhancing the reproduction of a digitally defined black and white image, comprising:

• means for receiving a digital signal representing the line-by-line scanned image,
• means for storing said digital signals during a plurality of successive scan lines,
• means for generating from said stored digital signals an identifier word representing the status of neighboring sectors surrounding each given sector of said image, and
• storage means containing data representative of a transformed image pattern corresponding to each element of the input pattern, and
• means for applying said identifier to said storage means to select a transformed sector matrix for each sector in the original image.