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Noise Measured with Average Motion Energy Difference Parameter

Noise can be defined as "An uncontrolled or unpredicted pattern of intensity fluctuations that is unwanted and does not contribute to the desired quality of a video image."

The images below illustrate how the motion energy difference parameter in ANSI T1.801.03-1996 can be used to quantify added noise in the output video. Two consecutive input images (frame 1 and frame 2) and their corresponding output images are displayed. The input and output temporal information (TI) images were computed by subtracting frame 1 from frame 2. Increasing values of TI, or motion, are shown as whiter areas in the TI images. The random noise present in the output manifests itself as "snow" in the output TI image. When a transmission channel adds noise, the (TI)2 values for the output are increased by the noise power as shown in the graph below. Some transmission channels can reduce, or threshold out, noise that is present in the input video signal. In this case, the output (dashed line) would have smaller (TI)2 values then the input (solid line) in the graph below.


Input noisein2.jpg - noisein1.jpg = noiseinti.jpg
  Frame 2   Frame 1   TI
Output noiseout2.jpg - noiseout1.jpg = noiseoutti.jpg