# Understanding Magnitude Spectrum of Images [closed]

I am facing problem in reading Fourier domain of a given image. I don't understand what to interpret from it. For instance, consider this image. Ok, so there is a dot in the middle, with some striking vertical and horizontal lines and there are also some circulating white lines which are low in intensity. What do I interpret from them? I basically converted the image to a monochrome image and then took the fourier transform of the monochrome image and displayed it along with original RGB image. Please help me to understand this. I tried every other resource but nothing got into my head. What are the uses of this interpretation? Also, in one of the answers here on DSP stackexchange, the images of sine and cosine were taken and then converted to spectrum which resulted white dots in it. I don't want to know that. I know that these dot represents the frequency component present in the sine and cosine. I want to understand everything with respect to my image only.

• My suggestion is to read any introductory textbook on signals and systems. Since you don't provide any reason why you calculated the image's FT in the first place, I'll assume it's a homework problem and then my second suggestion is, ask your instructor. – MBaz Apr 8 '18 at 16:10
• In the meantime, you might find this somewhat helpful. – A_A Apr 8 '18 at 22:08
• I know the concepts of signals and systems, Fourier transform, Laplace transform, etc. I am an electrical engineering student. I just want to know what does magnitude spectrum of an image means. – Himanshu Sharma Apr 9 '18 at 0:29

• so there is a dot in the middle: standard images have integer values between $0$ and $255$, hence the average is not zero. The average is the center dot. Remove it, and the global contrast may be better 