where w and h are the width and height of the image, c<hi xmlns="http://www.tei-c.org/ns/1.0" rend="italic subscript">i</hi> is the number of black pixels in the <hi xmlns="http://www.tei-c.org/ns/1.0" rend="italic">i</hi>-th column (= the corresponding value of the vertical projection profile) and l<hi xmlns="http://www.tei-c.org/ns/1.0" rend="italic subscript">j</hi> in the <hi xmlns="http://www.tei-c.org/ns/1.0" rend="italic">j</hi>-th line.