How to add noise Gaussian salt and pepper etc to image in Python with OpenCV

Question

I am wondering if there exists some functions in Python with OpenCV or any other python image processing library that adds Gaussian or salt and pepper noise to an image  For example  in MATLAB there exists straight-forward functions that do the same job   Or  how to add noise to an image using Python with OpenCV

User · Answer

just look at cv2 randu    or cv randn     it s all pretty similar to matlab already  i guess   let s play a bit       import cv2 import numpy as np   gt  gt  gt  im   np empty  5 5   np uint8    needs preallocated input image  gt  gt  gt  im array   248  168   58    2    1      uninitialized memory counts as random  too    fun               0  100    2    0  101             0    0  106    2    0           131    2    0   90    3             0  100    1    0   83    dtype uint8   gt  gt  gt  im   np zeros  5 5   np uint8    seriously now   gt  gt  gt  im array   0  0  0  0  0           0  0  0  0  0           0  0  0  0  0           0  0  0  0  0           0  0  0  0  0    dtype uint8   gt  gt  gt  cv2 randn im  0   99             normal array     0   76    0  129    0             0    0    0  188   27             0  152    0    0    0             0    0  134   79    0             0  181   36  128    0    dtype uint8   gt  gt  gt  cv2 randu im  0   99             uniform array   19  53   2  86  82           86  73  40  64  78           34  20  62  80   7           24  92  37  60  72           40  12  27  33  18    dtype uint8    to apply it to an existing image  just generate noise in the desired range  and add it   img       noise        image   img   noise

User · Answer

The Function adds gaussian   salt-pepper   poisson and speckle noise in an image   Parameters ---------- image   ndarray     Input image data  Will be converted to float  mode   str     One of the following strings  selecting the type of noise to add        gauss      Gaussian-distributed additive noise       poisson    Poisson-distributed noise generated from the data       s amp p        Replaces random pixels with 0 or 1       speckle    Multiplicative noise using out   image   n image where                 n is uniform noise with specified mean  amp  variance    import numpy as np import os import cv2 def noisy noise typ image      if noise typ     gauss         row col ch  image shape       mean   0       var   0 1       sigma   var  0 5       gauss   np random normal mean sigma  row col ch         gauss   gauss reshape row col ch        noisy   image   gauss       return noisy    elif noise typ     s amp p         row col ch   image shape       s vs p   0 5       amount   0 004       out   np copy image          Salt mode       num salt   np ceil amount   image size   s vs p        coords    np random randint 0  i - 1  int num salt                 for i in image shape        out coords    1          Pepper mode       num pepper   np ceil amount  image size    1  - s vs p         coords    np random randint 0  i - 1  int num pepper                 for i in image shape        out coords    0       return out   elif noise typ     poisson         vals   len np unique image         vals   2    np ceil np log2 vals         noisy   np random poisson image   vals    float vals        return noisy   elif noise typ    speckle         row col ch   image shape       gauss   np random randn row col ch        gauss   gauss reshape row col ch                noisy   image   image   gauss       return noisy

User · Answer

I don t know is there any method in Python API But you can use this simple code to add Salt-and-Pepper noise to an image   import numpy as np import random import cv2  def sp noise image prob               Add salt and pepper noise to image     prob  Probability of the noise             output   np zeros image shape np uint8      thres   1 - prob      for i in range image shape 0            for j in range image shape 1                rdn   random random               if rdn  lt  prob                  output i  j    0             elif rdn  gt  thres                  output i  j    255             else                  output i  j    image i  j      return output  image   cv2 imread  image jpg  0    Only for grayscale image noise img   sp noise image 0 05  cv2 imwrite  sp noise jpg   noise img

[python] How to add noise (Gaussian/salt and pepper etc) to image in Python with OpenCV

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