Image thickening processing method and apparatus

An image thickening processing apparatus, wherein a thickening processing is carried out on a binary image made up of a plurality of black picture elements and white picture elements, which are adjacent to one another along vertical and horizontal directions, the apparatus comprising:

• i) a judgment means for:
• setting each of the black picture elements as a black picture element of interest,
• detecting a vertically adjacent picture element, which is adjacent to said black picture element of interest along a single vertical direction, a horizontally adjacent picture element, which is adjacent to said black picture element of interest along a single horizontal direction, and an obliquely adjacent picture element, which is simultaneously adjacent to said vertically adjacent picture element, said horizontally adjacent picture element, and said black picture element of interest, and
• making judgments as to:
• a) whether a picture element, which is adjacent to said vertically adjacent picture element even further along said single vertical direction, is or is not a white picture element,
• b) whether a picture element, which is adjacent to said horizontally adjacent picture element even further along said single horizontal direction, is or is not a white picture element, and
• c) whether all of a picture element, which is adjacent to said obliquely adjacent picture element even further along said single vertical direction, a picture element, which is adjacent to said obliquely adjacent picture element even further along said single horizontal direction, and a picture element, which is adjacent to said obliquely adjacent picture element obliquely on the side opposite to said black picture element of interest, are or are not white picture elements, and
• ii) a thickening means for:
• a) setting said vertically adjacent picture element as a black picture element only in cases where said picture element, which is adjacent to said vertically adjacent picture element even further along said single vertical direction, has been judged by said judgment means as being a white picture element,
• b) setting said horizontally adjacent picture element as a black picture element only in cases where said picture element, which is adjacent to said horizontally adjacent picture element even further along said single horizontal direction, has been judged by said judgment means as being a white picture element, and
• c) setting said obliquely adjacent picture element as a black picture element only in cases where all of said picture element, which is adjacent to said obliquely adjacent picture element even further along said single vertical direction, said picture element, which is adjacent to said obliquely adjacent picture element even further along said single horizontal direction, and said picture element, which is adjacent to said obliquely adjacent picture element obliquely on the side opposite to said black picture element of interest, have been judged by said judgment means as being white picture elements.