CODEWITHSUNDEEP
pythonimageopencvpython-imaging-libraryimage-resizing
abdo Information
abdo Information

Reputation: 73

How to resize image without adding noise with python?

I have an image and I want to resize and expand this image without spoiling it.

The image:

Image work

The image size:

The image size I want it resized to:

I tried all the known methods:

  1. with PIL.Image: 
    from PIL import Image
path = "image.png"
w, h = 2000, 2100
img = Image.open(path)
img = img.resize((w, h), Image.ANTIALIAS)
img.save("re_image.png", "PNG")
  2. with cv2: 
    import cv2
path = "image.png"
w, h = 2000, 2100
img = cv2.imread(path)
img = cv2.resize(img, (w, h), interpolation = cv2.INTER_AREA)
cv2.imwrite("re_image.png", img)

The result is:

Result Image

Upvotes: 5

Views: 3409

Answers (3)

abdo Information
abdo Information

Reputation: 73

I created a simple function. Please give me your opinion.

The function is:

 import cv2, numpy as np

 def resize(path, sizes = (500, 800)):
         nw, nh = sizes
         g_img = cv2.imread(path)

         gw, gh = g_img.shape[0], g_img.shape[1]
         nw, nh = gw+510, gh+510
         pw, ph = int(nw/gw), int(nh/gh)
         if (pw == 0):pw = 1
         if (ph == 0):ph = 1
         nw, nh = pw*gw, ph*gh

         cvimg = np.zeros((nh,nw,3), np.uint8)

         for gy in range(gh):
             y, h = gy*ph, (gy*ph)+ph
             for gx in range(gw):
                 x, w = gx*pw, (gx*pw)+pw
                 cvimg[y:h, x:w] = g_img[gy:gy+1, gx:gx+1]

         nsize = [nw, nh]
         return cvimg, nsize

The result is:

Result

Upvotes: -1

sshashank124
sshashank124

Reputation: 32189

Don't use the ANTIALIAS filter. Since you want to preserve the sharpness of the edges, simply use the NEAREST filter. This filter is the default if no argument is passed to the resample parameter of Image.resize

img = img.resize((w, h))

This gives the expected result

Expected Result

Upvotes: 6

87VN0
87VN0

Reputation: 785

For your specific case which is a binary image, I think that you want to keep the edges sharp. Then I would suggest to use the flag cv2.INTER_NEAREST in your openCV implementation. You can check the effect of the different interpolation types, given in the documentation: https://docs.opencv.org/4.1.1/da/d54/group__imgproc__transform.html

I hope this helps!

Upvotes: 1

Related Questions