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

This worked for me. It has the ability to divide into n*m chunks. Pad your image accordingly.

def chunkify(img, block_width=4, block_height=4):
  shape = img.shape
  x_len = shape[0]//block_width
  y_len = shape[1]//block_height

  chunks = []
  x_indices = [i for i in range(0, shape[0]+1, block_width)]
  y_indices = [i for i in range(0, shape[1]+1, block_height)]

  shapes = list(zip(x_indices, y_indices))

  for i in range(len(shapes)):
      try:
        start_x = shapes[i][0]
        start_y = shapes[i][1]
        end_x = shapes[i+1][0]
        end_y = shapes[i+1][1]
        chunks.append( shapes[start_x:end_x][start_y:end_y] )
      except IndexError:
        print('End of Array')

  return chunks

https://github.com/QuantumNovice/ImageProcessing/blob/master/image_chunkify.py