[Tool] Discover if/how an image has been photoshopped
I'm kickstarting a program I'm working on that can help users know if an image has been altered or manipulated in some way. I thought the program might be of interest to those who have an interest in photographic forensics.
The program uses a variety of routines from the digital image forensics literature to provide information about irregularities in the image. Here is the current list of manipulation detection routines that the program implements
* Wavelet decomposition analysis to detect whether the image is all at the same focal length
* Edge detection routines to identify naturally blurred vs. artificially blurred areas (used to covered up tampering)
* Error level analysis to detect whether parts of the image come from sources with different error potential (i.e., two different images)
Noise enhancement to make small artifacts more visible
* Local Min/Max pixel highlighting to determine if the pixels errors display a normal variation
* Lighting gradient coloration to visually show where the light is coming from in an image, and is it consistently in one direction.
* Temperature Pseudocolor based on pixel intensity to identify odd or inconsistent coloration
* Pixel color randomization to show pixels that have the same RGB value more easily
* Extreme color highlighting to show where the pixels are pure white and black and if the colors are being clipped by the camera
* Thumbnail extraction from image to show what the picture might have originally looked like before manipulation
* Displaying Exif information to display properties concerning the image's history
* Extraction of Quantization tables used to save the image
* Minimum-Medium-Maximum RGB value for each pixel to identify coloration inconsistencies
* Save quality estimation to know what amount of compression has been used on the image
* Display the histogram of colors to see if a contrast filter has been applied
* Color Filter Array Estimation to know what color filter arrangement the specific camera uses to interpolate the colors.
The algorithms are accessed via Photoshop-like GUI that allows you open an image and use a drop-down menu to apply the algorithm to the image. You can also rotate the image, switch between results and the original, zoom in and out, cycle through previous results, and save the output as new images.
If this seems like something you would be interested in, feel free to check out the page and see what the program/output look like.