I am playing around with ERDAS and was implementing image difference on two rasters separated by interval of time. I was using a blue band raster and I created a default threshold for percentage change to be 20% and also did a standard deviation of 2.0.
The image gives two completely different outputs for the two types of measuring the difference, using the percentage change and standard deviation. This is the image.
The green describes the lower extreme, describing the reduction in change and the red describes the higher extreme, indicating the increase in change. Though I am not able to understand the difference between the standard deviation output and the percentage output and what is the significance of using one over the other?
Hope I was able to explain the question well. In the image the upper one is the percentage change and the lower one is the standard deviation.