python - 从图像 Python PIL 中去除噪声

Question

这里是新手。有形象我在图像上添加了噪音，我需要用噪音(或类似的东西)来清除图像。接下来是去噪算法:

If the brightness of the pixel is greater than the average brightness of the local neighborhood, then the brightness of the pixel is replaced with the average brightness of the surroundings.

from PIL import Image
import random
from multiprocessing import Pool
from multiprocessing.dummy import Pool as ThreadPool

img=Image.open('pic.bmp')
print(img.size)
randomenter=int(input('Enter numpix: '))
for numpix in range(0, randomenter):
    x=random.randint(0,int(img.size[0]-1))
    y=random.randint(0,int(img.size[1]-1))
    r=random.randint(0,255)
    g=random.randint(0,255)
    b=random.randint(0,255)
    img.putpixel((x,y),(r,g,b))
img.show()
img.save("noise.bmp", "BMP")

img2=Image.open("noise.bmp")
w, h = img2.size

pix=img2.copy()
for x in range(0,w-1):
    if x-1>0 and x<w:
        for y in range(0,h-1):
            if y-1>0 and y<h:
                local1=(0.3 * pix.getpixel((x-1,y-1))[0]) + (0.59 * pix.getpixel((x-1,y-1))[1]) + (0.11 * pix.getpixel((x-1,y-1))[2])
                local2=(0.3 * pix.getpixel((x-1,y))[0]) + (0.59 * pix.getpixel((x-1,y))[1]) + (0.11 * pix.getpixel((x-1,y))[2])
                local3=(0.3 * pix.getpixel((x-1,y+1))[0]) + (0.59 * pix.getpixel((x-1,y+1))[1]) + (0.11 * pix.getpixel((x-1,y+1))[2])
                local4=(0.3 * pix.getpixel((x,y-1))[0]) + (0.59 * pix.getpixel((x,y-1))[1]) + (0.11 * pix.getpixel((x,y-1))[2])
                LOCAL5=(0.3 * pix.getpixel((x,y))[0]) + (0.59 * pix.getpixel((x,y))[1]) + (0.11 * pix.getpixel((x,y))[2])
                local6=(0.3 * pix.getpixel((x,y+1))[0]) + (0.59 * pix.getpixel((x,y+1))[1]) + (0.11 * pix.getpixel((x,y+1))[2])
                local7=(0.3 * pix.getpixel((x+1,y-1))[0]) + (0.59 * pix.getpixel((x+1,y-1))[1]) + (0.11 * pix.getpixel((x+1,y-1))[2])
                local8=(0.3 * pix.getpixel((x+1,y))[0]) + (0.59 * pix.getpixel((x+1,y))[1]) + (0.11 * pix.getpixel((x+1,y))[2])
                local9=(0.3 * pix.getpixel((x+1,y+1))[0]) + (0.59 * pix.getpixel((x+1,y+1))[1]) + (0.11 * pix.getpixel((x+1,y+1))[2])
                localall=(local1+local2+local3+local4+local6+local7+local8+local9)/8
                if LOCAL5<localall:
                    img2.putpixel((x,y),(int(pix.getpixel((x,y))[0]*localall/LOCAL5),int(pix.getpixel((x,y))[1]*localall/LOCAL5),int(pix.getpixel((x,y))[2]*localall/LOCAL5)))
img2.show()

亮度变化瞬间出现问题。官方码头没有关于这个案例的详细信息。有什么解决办法吗？

Answer 1

首先，您需要创建图像副本以将数据写入:imgCopy = img.copy()。否则，您的噪声校正像素将影响尚未触及的像素的校正。在您的 else 语句中，您只需标准化中间像素，然后将其乘以您计算的平均亮度:

imgCopy[i, j] = imgCopy[i, j] * local / nuzh