Image processing apparatus having shadow composition capability using binary data thinning and thickening circuits and preset thinning and thickening width data

An image processing apparatus having a scanning unit reading out image data by scanning a document, an image processing unit carrying out an image processing of the image data supplied by the scanning unit, and a recording unit outputting an image supplied by the image processing unit for recording the image, said image processing unit comprising:

• control means for allowing real-time operations of the scanning unit and the recording unit;
• binarizing means for generating signals indicative of binary data from the image data supplied by said scanning unit;
• preset data generating means for generating either a preset thinning width or a preset thickening width;
• a thinning circuit for carrying out a choking process in accordance with said preset thinning width whereby the binary data supplied by the binarizing means is moved either in a main scanning direction or in a sub scanning direction and a portion of an original image is removed so a to obtain a choked image;
• a thickening circuit for carrying out a spreading process in accordance with said preset thickening width whereby the supplied binary data is moved either in the main scanning direction or in the sub scanning direction and an additional image portion is added to the original image so as to obtain a spread image;
• and
• image composition means for generating a composite image of the choked image supplied by the thinning circuit and the spread image supplied by the thickening circuit so that a shadow is added to the original image.