Comparator Sample Application

Image analysis
The Operator image is being compared to the Source image. The statical measure of similarity is the correlation coefficient. A value of 1.00 would mean the images are identical. In this case a value of 0.72 indicates a difference between the two images, that is, something has changed.

Image comparison
The Operator image is compared to the Source image and the Result image is composed of the difference. The vehicle in the foreground is immediately obvious.

Many of the functions in the Victor Library allow multiple images to be compared, combined, or analyzed. These techniques can be used for

• motion detection,
• finding alignment or registration marks,
• pattern matching, and
• special effects.

These important functions can be arranged in three catagories:

Combining images		Comparing images		Analyzing images
addimage addtexture andimage bleach cover coverclear divideimage isolate multiplyimage multiplynegative orimage wtaverage		correlateimages darker difference differenceabs lighter subimage xorimage		calcavglevel correlationcoef calchisto pixelcount sortpixelsbyval

The application, Comparator, contains all these Victor Library functions so they can be tested with any images. Download VB Comparator and source code (96 Kb) or C# Comparator and source code (120 Kb). Requires the Victor Library v 5.6 commercial release or eval version.