Airphoto SE: this software is useful for the UAVs used for the aerial photography and gives a great picture due to all the features present that are necessary for the rectification of the oblique aerial imagery with the geo referenced output. The best part is that it allows for good quality large picture as there are four processors for multithreading that can work on the different parts f the same large photo and all at the same time. The various distortion factors can be controlled in this software. This can be used both by the beginners and the experts in this field. You can even combine your photos with maps, orthophotos or the pictures from satellite.
Fiji: this is software package that is aimed at image processing. There is use of Java, Java3D and many plugins for menu structure that is coherent in nature for the distribution of image J. Image J: this is a program that is aimed at image processing and is available on the public domain. The main feature of this software is that it can display, edit as well as analyze, process and save the print in 8-bit, 16-bit as well as 32-bit. If you want to know about the area and the value of the pixels in the selected area then this software is capable of doing that too.