Patent ID: 7746505

Claim:
An image quality improving apparatus comprising: a first unit estimating edge pixels of a text area in a predetermined detection area to be edge-detected from an input picture data containing a text and an image; and a second unit judging actual edge pixels based upon a number of edge-estimated pixels in a multiple window area and saturation values of individual edge-estimated pixels, and emphasizing individual actual edge pixels with different edge emphasis coefficients according to saturation values of the respective actual edge pixels wherein the first unit comprises: a lightness variation measuring section measuring lightness variation from individual pixels in the predetermined detection area to be edge-detected; and an edge estimating section calculating binary data of the individual pixels from multiple windows collectively, the binary data being composed by the lightness variation measuring section according to different sampling procedures composing the multiple windows from an area having lightness variation, the edge estimating section also judging connectedness and similarity of the calculated binary data according to the individual windows, to estimate whether a given pixel is an edge.