I am trying to use Imagej for my thesis. I have few sets of five photographs (black and white), I would like to make an average of every five photographs. I wrote a simple macro (code below) to do this, but I was not sure whether the output is correct. So I made a histogram for every single photography and made an average value of Mean grey value (using handheld calculator), I was surprised, when I found out, that the Mean grey value in histogram of averaged photo was different. To exclude possible mistake in my algorithm I tried the Grouped Z Projection, the histogram Mean grey value was again completely different value. To exclude possible problem of Imagej I tried GraphicsMagick (
gm convert -average), then I made histogram with another different Mean grey value.
I thank in advance for any help, especially help to explain all these different values:
input = "/home/user/Documents/Thesis/IRPHOTO/input/"; output = "/home/user/Documents/Thesis/IRPHOTO/output/"; setBatchMode(true); list = getFileList(input); i=0; open(input + list[i]); id1 = getImageID; j = i + 1; open(input + list[j]); id2 = getImageID; k = i + 2; open(input + list[k]); id3 = getImageID; l = i + 3; open(input + list[l]); id4 = getImageID; m = i + 4; open(input + list[m]); id5 = getImageID; id1=(id1 + id2 + id3 + id4 + id5)/5; i = i + 50; saveAs("Jpeg", output + i); close(); setBatchMode(false);