Patent ID: 7636472

Claim:
An image quality correction apparatus comprising: an image data selecting unit for, when inputted image data (hereinafter referred to as input image data) includes image data which causes degradation in image quality (hereinafter referred to as degradation factor data) when subjecting the input image data to correction of image quality, removing the degradation factor data from the input image data; a luminous histogram formation unit for forming a luminous histogram of image data that is outputted from the image data selecting unit; a correction amount calculation unit for calculating an amount of correction on the basis of the luminous histogram formed by the luminous histogram formation unit; and an image quality correction unit for correcting the input image data on the basis of the amount of correction that is calculated by the correction amount calculation unit; wherein said degradation factor data are pixel data which constitute a character area and are included in the input image data; wherein said image data selecting unit comprises: a luminous color-difference calculation unit for calculating a luminous value and color-difference values for each pixel, from the input image data; a projecting level detection unit for detecting a locally projecting level from the luminous histogram that is formed using all pixels of the input image data; a pixel information setting unit for detecting color-difference values whose frequencies are equal to or higher than a predetermined value, from the color-difference values of the pixels having the luminous value of the projecting level which is detected by the projecting level detection unit and setting the detected color-difference values and the luminous value of the projecting level, as pixel information of pixels which constitute the character area; and a count judgement unit for judging whether a target pixel having the luminous value and the color-difference values outputted from the luminous color-difference calculation unit is a component of the character area or not, on the basis of the luminous values and the color-difference values which are obtained from the pixel information that is set by the pixel information setting unit, and outputting the luminous value of the target pixel only when the target pixel is not a component of the character area; wherein said luminous histogram formation unit forms a luminous histogram using the luminous values of all pixels of the input image data, and a luminous histogram using the luminous values of pixels outputted from the count judgement unit; and wherein said correction amount calculation unit calculates an output of correction on the basis of the luminous histogram that is formed by using the luminous values of pixels outputted from the count judgement unit.