Method and apparatus for reducing motion artifacts and noise in video image processing

A method for reducing noise and motion artifacts in a video image by filtering pixel values of a first frame of video having filtered pixel values, and a second frame of video having unfiltered pixel values, the method comprising the steps of:

• (a) selecting a pixel of interest from among pixels in the first frame of video;
• (b) computing difference values of the pixel of interest and pixels surrounding the pixel of interest, wherein the difference values are the differences between the filtered pixel value of a pixel in the first frame and the unfiltered pixel value of the same pixel in the second frame;
• (c) averaging the difference values of the pixels surrounding the pixel of interest to obtain a motion value;
• and
• (d) temporally filtering the filtered pixel value of the pixel of interest according to the motion value and taking a weighted average of the difference values based on the motion value.

A method for reducing noise and motion artifacts in a video image by filtering pixel values of a first frame of video having filtered pixel values, and a second frame of video having unfiltered pixel values, the method comprising the steps of:

• (a) selecting a pixel of interest from among pixels in the first frame of video;
• (b) computing difference values of the pixel of interest and pixels surrounding the pixel of interest, wherein each difference value is the difference between the filtered pixel value of a pixel in the first frame and the unfiltered pixel value of the corresponding pixel in the second frame;
• (c) averaging the difference values for the pixels surrounding the pixel of interest to obtain a motion value;
• and
• (d) temporally filtering the filtered pixel value of the pixel of interest according to the motion value by adding an output difference value to the pixel of interest, wherein the output difference value is based on a combination of the difference value of the pixel of interest and the average difference value of the pixels surrounding the pixel of interest and taking a weighted average of the difference values based on the motion value.

An apparatus for reducing noise and motion artifacts in pixels of a displayable video image by filtering pixel values of the pixels based on a first frame of video having filtered pixel values and a second frame of video having unfiltered pixel values, the apparatus comprising:

• a subtractor to produce difference values by computing a difference between the filtered pixel values of the first frame and the unfiltered pixel values of the second frame;
• a spatial filter, associated with the subtractor, to compute a motion value of a pixel of interest in the first frame of video by averaging the difference values of pre-selected pixels surrounding the pixel of interest;
• a temporal filter, coupled to the spatial filter, to receive the motion value and filter the pixel value of the pixel of interest according to the motion value, wherein the temporal filter further comprises:
• (a) a difference filter to produce an output difference value of the pixel of interest based on the motion value;
• and (b) an adder for adding the output difference value to the first frame filtered pixel value of the pixel of interest;
• and
• a control unit and a weighted averaging unit that receives a control signal from the control unit, wherein the control signal developed by the control unit selects different weights and ratios of the difference value and the motion value, both signals having been scaled to the same relative magnitude.