| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus capable of suppressing occurrence of a tone jump in a digital image through the improvement of bit resolution so as to prevent an edge part such as a contour from being blurred. <P>SOLUTION: In the case of converting an original signal into an extended signal whose bit resolution is improved more than that of the original signal by increasing n(1) bits to a least significant digit of the original signal resulting from expressing each pixel of the digital image in N(8) bits so as to extend the N(8) bits into M(9) bits, a correction value depending on a difference between the value of the original signal of each pixel and an average value of pixel values of several surrounding pixels of each pixel is added to the original signal to obtain an estimate signal whereby the precision of the value of the original signal of each pixel is improved, the value of the estimate signal is multiplied by a multiple of 2<SP>n</SP>(=a multiple of 2<SP>1</SP>) and thereafter the lower-order digits are rounded off, the estimate signal is converted into the extended signal in higher-order M(9) bits, from which the digital image is formed. In this case, the estimate signal is decided so that the estimate signal returns to the original signal when the lower-order digits of the estimate signal are rounded off. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
