The graphs in REGISTAX form an important part of the processing feedback . To the right you see a graph that is common during the alignment-stage. It shows in red the amount of data for different spatial frequencies (resolution). Sharp images have a longer tail (to the right) than blurred images. The settings of Quality and FFT should always be to the right of the bend in the graph.
This last graph is much alike the above one but is the one shown during optimisation. A green vertical line shows which image the optimisation is working on. The image is all the time optimized to show the maximum value on the top of the graph, this means that after an optimisation the graph actually might look to have increased but actually the maximum decreased and the differences were minimized.
After the alignment another type of graph appears. The red line now shows the quality for every single image in the sequence (ordered) and the blue line shows the sum of squared differences between the alignment areas (FFT-size). Notice that the reference image (difference = 0) is not the best quality but indeed one of the better images. The first half of the frames shows a decreasing quality but the differences are not dramatically decreasing. The second half decreased further in quality and the difference suddenly rise.
