Home / YUVTools / YUV Motion Analysis

YUV Analyzer:

YUV Analyzer actually contains four tools, PSNR calculation, YUV comparison, data overlay and checking motion.
  1. PSNR calculation between two image clips
  2. Comparison between two image clips
  3. Overlaying information on top of an image
  4. Checking motion between two consecutive frames

Motion Estimation

This module allows you to check and verify whether any image blocks, or a group of blocks, are moved between two adjacent frames. For any frames (except the first frame), you can select certain area in the image (at 8x8 block level), and interactively move the selected blocks in any direction, up, down, left or right. The modified image can be compared with previous frame, the difference will be displayed.

First, select "Motion Estimation" from top menu "YUV Analyzer", or directly click on  from the toolbar. In the pop up dialog, you can load a video clip and start to analyze the motion/difference between two adjacent frames.

              (Click on above image to display a full resolution image)

The image displayed will be the difference image between the first frame and the second frame. Then you can click on ">" button to step frame by frame, to display the difference images.

There are two ways to display the difference images, in grey scale or in uniform color.

  • While in grey scale image mode, you can drag the slide bar to adjust the brightness of the image;
  • If in "Uniform color" mode, you can choose to display the pixels whose difference values (summed absolute difference values) is between certain ranges. The uniform color itself can also be changed.

You can also select which image to display:

  • The difference image only, in grey scale or in uniform color;
  • Difference image on top of the previous frame. If difference image is in grey scale mode, then only the previous image itself is displayed; If difference image is in uniform color mode, the pixels whose difference values are within the specified range
  • Difference image on top of the current frame. The whole will be covered with a transparent layer. You can select an area to move, and the selected area (group of blocks) will be in clear and complete transparent. To select an area in the current frame, you need press and hold "Ctrl" key, and click and hold mouse left button, then drag to form a rectangle area.  There are also 3 buttons for "Select All", "Select None" and "Reverse" current selection. 

              (Click on above image to display a full resolution image)

The selection is block (8x8) based. After you finish the selection, you can click on 4 moving buttons to move the selected blocks along any direction (up and down, or left and right), at any moving steps.  In the above example, the selected area was moved to the right for 8 pixels.   After the movement, you can check the difference image again, and you can also save the movement back to the YUV image file.

In this example, if you switch to display the difference image again, you will see the following image, notice that the pixels in the moved area have no difference compared to previous frame (frame #1):

              (Click on above image to display a full resolution image)

 If you have several selection rectangles overlapped, each rectangle will reverse previous rectangles

              (Click on above image to display a full resolution image)

By clicking on the displayed image (at any display mode), you can check the pixel values inside the 8x8 block you clicked on, for the current frame as well as the same location of the previous frame. The following dialog will pop up to show the detailed information:

              (Click on above image to display a full resolution image)

 
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