Ryan_m_b said:
Why would you think I know that and what makes any of that "real"?
Sorry, I thought you meant it as a joke.
I think that this example is real:
The original photo is "filled" with noise which has some distinct feature. You Fourier transform (FT) the noisy picture and will find this feature in the Fourier transform. Remove it from the transform and make the inverse Fourier transform (IFT). Then you'll get the picture to the right.
Say you have a photo of a car driving by. Due to the speed of the car ( crossing the photo with a shutter time = 1/100 sec. ) the car will be blurred on the photo. Now you take two sheets of paper, draw a dot on one of them and a line on the other ( blurred dot ). The line must exactly be as long as the car has been moving on the photo. Also their moving angle must be the same. FT the dot-picture to D, FT the line-picture to L, FT the photo of the car to C. Then:
IFT( C * ( D / L ) ) and you will have a photo of the car, where you can read its registration number.
Hough transforms are used to recognize lines, circles, parabolas and other mathematical shapes. If such a "known" shape occurs in some photo, the Hough transform will find it and will determine its exact size and location within 1/10 of a pixel-distance. Having a "standard-length" as well in the picture, a computer can calculate very accurate dimension in the picture, check "ovality?" as of things meant to be circular, and so on.
Remember that working machines are often moving very fast, thus the human eye sees nothing. A camera needs perhaps 2μs, using a stroboscope, to see everything in the picture ( well, at least after the computer has calculated for another 100ms ).