image comparison menu

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This menu is for comparing two greyscale images. It offers the ability to flash instantaneously between two different images, so you can compare parts of the images without having to move your eyes. It also provides an ability to mechanically examine all of the images systematically, step by step, without missing any features.

The menu supports two different modes of image display. The first mode works as follows:

  1. You enter the names of the images you want to compare in the Image 1 and Image 2 fields. The images don't have to be the same size; if they are different, Image 2 is stretched to fit the size of Image 1.
  2. You set the display width.
  3. You click on DISPLAY. Image 1 will appear. To flash to Image 2, click button 2 on the mouse while the pointer is on the image. Click button 2 again to switch back to Image 1.

You can make blowups with button 1, as usual. You can delete blowups or the main image with button 3, as usual. The Currently displayed image menu field shows which of the two images is currently displayed. You can also determine this by looking at the edges of the image: a green border means that Image 1 is visible, a red border means Image 2.

In systematic scan mode, the system displays pieces of the images (magnified) in a systematic way that lets you examine every square inch of the images without missing anything. This works as follows:

  1. You enter the image names in the menu.
  2. You specify how you want the image subdivided into pieces by entering a number in the Subdivision factor menu field. If you enter 5 for example, the system will chop the image up into 25 pieces (5 columns by 5 rows).
  3. You specify how much overlap there should between subdivided pieces. 7 percent is generally a good value here.
  4. You click on SYSTEMATIC SCAN. The system first displays a small picture of the entire image area, with a red box indicating the piece of the image that is currently magnified. It then displays the magnified image of the piece. As in DISPLAY mode, you use button 2 to flash between images. Button 3, however, now has a different function: you use it to tell the system to move to a different piece of the image. If you click with button 3 on the small, entire image, you will get a blowup of the piece of the image that encloses the position of your click. If you click with button 3 in the magnified image, the system displays the piece that is to the left, right, above or below the currently-displayed piece. You control which direction the system moves by clicking near the left, right, top or botton edges of the magnified image.

You can cover the entire image by always clicking near the right edge of the magnified view, because when the piece hits the right-hand side of the entire image, it moves to the leftmost position on the next row up. The same thing applies to clicking near the top of the magnified image: when you go 'up' from the top, it moves to the bottom position on the next row to the right.

The system shows already-examined pieces of the image with a blue box, so you can see what you've already covered. The currently-displayed piece is always highlighted in red.