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使用Python-OpenCV向图片添加噪声的实现(高斯噪声、椒盐噪声)

更新时间:2020-07-04 02:36 作者:startmvc
在matlab中,存在执行直接得函数来添加高斯噪声和椒盐噪声。Python-OpenCV中虽然不存在直接

在matlab中,存在执行直接得函数来添加高斯噪声和椒盐噪声。Python-OpenCV中虽然不存在直接得函数,但是很容易使用相关的函数来实现。

代码:


import numpy as np
import random
import cv2

def sp_noise(image,prob):
 '''
 添加椒盐噪声
 prob:噪声比例 
 '''
 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 < prob:
 output[i][j] = 0
 elif rdn > thres:
 output[i][j] = 255
 else:
 output[i][j] = image[i][j]
 return output


def gasuss_noise(image, mean=0, var=0.001):
 ''' 
 添加高斯噪声
 mean : 均值 
 var : 方差
 '''
 image = np.array(image/255, dtype=float)
 noise = np.random.normal(mean, var ** 0.5, image.shape)
 out = image + noise
 if out.min() < 0:
 low_clip = -1.
 else:
 low_clip = 0.
 out = np.clip(out, low_clip, 1.0)
 out = np.uint8(out*255)
 #cv.imshow("gasuss", out)
 return out

可见,只要我们得到满足某个分布的多维数组,就能作为噪声添加到图片中。

例如:


import cv2
import numpy as np

>>> im = np.empty((5,5), np.uint8) # needs preallocated input image
>>> 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)
>>> im = np.zeros((5,5), np.uint8) # seriously now.
>>> 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)
>>> 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)
>>> 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)

然后再:


img = ...
noise = ...

image = img + noise

参考链接:

1、https://stackoverflow.com/questions/22937589/how-to-add-noise-gaussian-salt-and-pepper-etc-to-image-in-python-with-opencv#

2、https://stackoverflow.com/questions/14435632/impulse-gaussian-and-salt-and-pepper-noise-with-opencv#

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。