Manipulating Images

I'm going to introduce you about two functions of manipulating images

1.Copying an Image

Copying which allows you to create a new image independent of the original is frequently used in our life. But, do you know how it works?

This is how computer works when you copy an image

*assume baboon as a png image*

from PIL import image Picture of Memory

import cv2

import numpy as np

baboon = cv2.imread("baboon.png") ----> Stored in 00100010 memory

baboon = np.array(Image.open("baboon.png"))

Use id function to find the object's memory address

id(baboon):00100010

A=baboon ----> Assign the baboon array to "A" (Copying)

id(A):00100010 ---> The memory address is same as the original

B=baboon.copy()

id(B):10101010 ----> The memory address is different

See how the memory address works!!

baboon[;,;,] = 0 -----> Set all the elements to the baboon array to ZERO

The array "A" will change as it points to the same locations in memory

"Baboon" "A" "B"

00100010 00100010 10101010

*Both the baboon array of array "A" will be zero but because we used the copy method array "B" will be unaffected*

2.Flipping images

= changes the image orientation

Flip an image by changing the index value of pixel or intensity

ex) Convert the column indexes to row indexes the image will have a different orientation

For color images *Cube format*

= Convert all the color channels at the same time

Flipping images using PIL & Open CV

1.Using PIL

from PIL import ImageOps

im_flip = ImageOps.flip(Image) ----> flip function to flip the image

im_mirror = ImageOps.mirror(Image) -----> mirror the image using the mirror function

image.transpose(Image.FLIP_TOP_BUTTOM) ----> using transpose() method/the image module has built in attributes to

describe the type of flip

2.Using Open CV

import cv2

im_flip = cv2.flip(Image,0) ----> parameter = flipcode/if flipcode is 0, flip vertically around the 4 axis

im_flip = cv2.rotate(Image, cv2.Rotate_90_CLOCKWISE) ---> rotate() function; open CV module has built-in

attributes to describe the type of flip

---> Values are represented by integers

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