DWT3.py

import numpy as np
import cv2
import sys
import os


def waveleteTransform(img):

    # print(img)
    image = img.astype(np.float)
    height, width = image.shape[:2]
    result = np.zeros((height, width, 3), np.float)

    # Horizontal processing
    width2 = width / 2
    for i in range(height):

        for j in range(0, width - 1, 2):

            j1 = (int) (j + 1)
            j2 = (int) (j / 2)
            width3 = (int) (width2 + j2)

            result[i, j2] = (( image[i, j] + image[i, j1] ) / 2)
            result[i, width3] = ((image[i, j] - image[i, j1]) / 2)

    # copy array
    image = np.copy(result)

    # Vertical processing:
    height2 = height / 2
    for i in range(0, height - 1, 2):
        for j in range(0, width):

            i1 = (int) (i + 1)
            i2 = (int) (i / 2)
            height3 = (int) (height2 + i2)

            result[i2, j] = (image[i, j] + image[i1, j]) / 2
            result[height3, j] = (image[i, j] - image[i1, j]) / 2
    resultimg = result.astype(np.uint8)
    return resultimg


def inverseWaveleteTransform(img):
    image = img.astype(np.float)
    nr, nc = image.shape[:2]
    result = np.zeros((nr, nc, 3), np.float)
    nr2 = nr / 2

    for i in range(0, nr - 1, 2):
        for j in range(0, nc):

            i1 = (int) (i + 1)
            i2 = (int) (i / 2)
            nr3 = (int) (nr2 + i2)

            result[i, j] = ((image[i2, j] / 2) + (image[nr3, j] / 2)) * 2
            result[i1, j] = ((image[i2, j] / 2) - (image[nr3, j] / 2)) * 2

    # //copy array
    image = np.copy(result)

    # // Horizontal processing:
    nc2 = nc / 2
    for i in range(0, nr):
        for j in range(0, nc - 1, 2):

            j1 = (int) (j + 1)
            j2 = (int) (j / 2)
            nc3 = (int) (j2 + nc2)
            result[i, j] = ((image[i, j2] / 2) + (image[i, nc3] / 2)) * 2
            result[i, j1] = ((image[i, j2] / 2) - (image[i, nc3] / 2)) * 2

    resultimg = result.astype(np.uint8)
    return resultimg


if __name__ == '__main__':

        # loadImage & copy image
    image = cv2.imread(sys.argv[1])

    image2 = waveleteTransform(image)

    image3 = inverseWaveleteTransform(image2)

    cv2.imshow('base Image', image)
    cv2.imshow('DWT', image2)
    cv2.imshow('Inverse DWT', image3)

    a, ext = os.path.splitext(os.path.basename(sys.argv[1]))
    a = a + "D"
    print( a)
    b = a + ext
    print (b)
    cv2.imwrite('/tmp/image3.jpeg', image3)
    cv2.waitKey(0)
    cv2.destroyAllWindows()