What do you mean by histogram of a digital image? How the image enhancement is achieved by histogram manipulation. Do the histogram equalization on a $6464$ image which has $8$ discrete pixel levels $(0-7)$ and its histogram is given below. Transform it into a histogram equalized image also with $8$ discrete gray levels in the range $(0-7).$

$\backslash$table$[[$Gray levels,$0,1,2,3,4,5,6,7],[$No$.$ of pixels,$790,1023,850,656,329,245,122,81]]$