| 摘要 |
PROBLEM TO BE SOLVED: To prevent fluctuation in the unit of blocks. SOLUTION: A motion detection circuit 9 obtains a correlation value between a reference image block and a block of a current image from memories 2, 8 and provides an output to a correlation mean value arithmetic circuit 35. The correlation mean value arithmetic circuit 35 averages a correlation between the reference image block and a block of the current image and a correlation between the reference image block and a surrounding block of a noted block of the current image. A coefficient arithmetic circuit 36 calculates an NR coefficient based on the average value of the correlation values. A subtractor 37 obtains an inter-frame non-correlation component from a difference of image data before and after one frame, a noise extract circuit 34 extracts noise from a non-correlation component and the NR coefficient. A subtractor 33 eliminates the noise component from the input image data and provide an output. Since the NR coefficient is decided based on the correlation value between the reference image block and a surrounding block of the current image block, the difference of the noise reduction effect in the unit of block is not increased and the fluctuation in the unit of blocks is prevented. |
