Convolution in Image Processing? I got the concept of Convolution in signal processing from a video lecture that it is method to get the area overlapped between two signals when one signal is flipped over and traversed over another signal and that it allows for getting combined effect of two signals during that traversal. But how this concept is applied in image processing. 

How a function of some arbitrary window size is used to be traversed over the image in order to get effect and how convolution is actually taking place there ?
Convolution is typically used in the context of filtering. You have an image, $I$, a filter kernel, $K$, and you convolve them together to get a filtered image, $J$:

$J = I \star K$

where $\star$ denotes convolution.

The nature of the filtering operation will be determined by the coefficients of the filter kernel, $K$.