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Target Detection Algorithm in CCD

by Technical Evangelist on ‎03-10-2016 12:47 PM - edited on ‎03-21-2016 03:34 PM by Anonymous (490 Views)

Question

In the online help for Analysis step section "Target Detection" it says:

"The target detection algorithm compares the difference between the mean pixel value of each moving window and the coherence image pixel value with the specified threshold value divided by the standard deviation value of each moving window. If this difference is larger than the mentioned product, the pixel is detected"

 

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1. "the coherence image pixel value with the specified threshold value divided by the standard deviation value of each moving window"
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Which pixel value does "the coherence image pixel value" in this sentence indicate? Is it all the pixels within the moving window?

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2. "If this difference is larger than the mentioned product"
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Which data does "mentioned product" indicate?

Answer

The Coherence image pixel value refers to each pixel in the Coherence image. We are trying to determine whether or not each pixel in the Coherence image is a "Target". We do this by comparing each Coherence image pixel to its neighbors - is a Coherence image pixel similar to its neighbors or anomalous?? We do this by computing the average of the neighboring pixels in the moving window (size set in the CCD Analysis tool). The Threshold default value of "2" is 2 standard deviations. If the Coherence pixel is within 2 standard deviations of the moving window average of its neighbors, it is NOT anomalous and is assigned a value of "0". If it is outside 2 standard deviations, it is assumed a "Target" and assigned a valor of 1.

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