Image data processing apparatus with selective processing filters

An image data processing apparatus which applies processing to original image data input from an image data storage unit and then supplies the processed image data to an image output unit, wherein said original image data input to the said image data processing apparatus is data comprised of data L* representing saturation and data a*b* representing hue and brightness, expressed under a uniform color space, said image data processing apparatus comprising:

• an image data statistical processing unit which receives only the image data a*b* data of the original image data from the image data storage unit and extracts and performs statistical processing on the picture element distribution in the picture expressed by the original image data, said image data statistical processing unit extracting the characteristics of the picture element distribution by calculating whether the change of color between adjoining picture elements is large or small, for all of the picture as a whole;
• an image data decision unit which decides, based on the results of the statistical processing by the image data statistical processing unit and the determination whether the change of color is large or small, whether the picture belongs to a first kind of picture suited for sharpening processing or a second kind of picture suited for smoothing processing;
• a filter selection unit which selects a first type of filter when it is judged, based on the results of the decision by the image data decision unit, that the picture belongs to the first kind and selects a second type of filter, of a filter size larger than the first type, when it is judged that the picture belongs to the second kind;
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• a filter processing unit which uses the first type of filter or the second type of filter, as selected by the filter selection unit, to apply filter processing on the original image data from the image data storage unit and supplies the resultant image data to the image output unit.

An image data processing apparatus which applies processing to original image data input from an image data storage unit and then supplies the processed image data to an output unit, wherein said original image data input is data comprised of data L* representing saturation and data a*b* representing hue and brightness, respectively, expressed under a uniform color space, said image data processing apparatus comprising:

• an image data statistical processing unit which receives only the data a*b* of the original image data, input thereto from the image data storage unit, and extracts and performs statistical processing on the picture element distribution in the picture expressed by the original image data, said image data statistical processing unit extracting the characteristics of the picture element distribution by dividing the picture, as a whole, into clusters of various picture elements having identical picture element attributes;
• an image data decision unit which decides, in accordance with the results of the statistical processing by the image data statistical processing unit, whether the picture belongs to a first kind of pictures suited for sharpening process or a second kind of picture suited for smoothing processing in accordance with whether the number of the divided picture element clusters is large;
• a filter selection unit which selects a first type of filter when it is judged, based on the results of the decision by the image data decision unit, that the picture belongs to the first kind and selects a second type of filter, of a filter size larger than the first type, when it is judged that the picture belongs to the second kind;
• and
• a filter processing unit which uses the selected one of the first type of filter and the second type of filter, as selected by the filter selection unit, to apply filter processing on the original image data from the image data storage unit and supplies the resultant image data to the image output unit.