Divide an image into 5x5 blocks in python and compute histogram for each block

Question

Using Python, I have to:

• Divide a Test_Image and Reference_image into 5x5 blocks,
• Compute a histogram for each block, and

Answer 1

I have write this code two automatically split image into n rows and m columns. m and n are arguments and it is easily modifiable. After that it is easy compute histogram for each block which are also saving into the folder named patches.

# Image path, number of rows 
# and number of columns 
# should be provided as an arguments
import cv2
import sys
import os


if not os.path.exists('patches'):
    os.makedirs('patches')



nRows = int(sys.argv[2])
# Number of columns
mCols = int(sys.argv[3])

# Reading image
img = cv2.imread(sys.argv[1])
#print img

#cv2.imshow('image',img)

# Dimensions of the image
sizeX = img.shape[1]
sizeY = img.shape[0]

print(img.shape)


for i in range(0,nRows):
    for j in range(0, mCols):
        roi = img[i*sizeY/nRows:i*sizeY/nRows + sizeY/nRows ,j*sizeX/mCols:j*sizeX/mCols + sizeX/mCols]
        cv2.imshow('rois'+str(i)+str(j), roi)
                cv2.imwrite('patches/patch_'+str(i)+str(j)+".jpg", roi)



cv2.waitKey()