in python can it be like this?:

import matplotlib.pyplot as plt

img_vec=plt.imread('path to image')

in Matlab it would be as simple as:

img_vector = img(:); % img is your input gray scale image

and if youh have a RGB imageyou can first convert it to grayscale image using rgb2gray(RGB) and then use the above code.

imread method in class Highgui if you use OpenCV lib.

Images as a two dimensional array of pixels can be converted to one dimensional vector representation by rearranging its row sequentially. This is a horizontal and vertical scanning process. It is used in progressive scanning for image graphical display.

Best wishes

Thank you everyone.