Hey Robert
I am now using the R band and have created a transformation factor. In order to create a transformation factor, I created water, forest, urban, and bare earth shapefiles and extracted by mask using the features. Then, I only used the forest raster, to look at the mean pixel value in properties for all three NAIP images and took the average value. The transformation factor is divided by the image with the different contrast over the middle image. The middle image and the bottom image have the same mean value so I only used the middle for the transformation factor calculation.
The transformation factor (0.91) is multiplied by the top image (the image different in contrast than the other two) in raster calculator. The same calculation was performed for the middle and bottom images. This allowed me to see the range in values for the upper, middle, and bottom R-band images.
Once I determined the range, I then went to the stretch group box and changed the statistics to min-max so I was able to adjust the values. For the upper image, I changed it to 45-238. The middle and lower are very similar in value...24 and 26 to 238. The images, now, are identical and have no contrasting issues.
What do you think?
Thanks
James