平滑放大图像的像素

Question

我非常擅长编程，试图学习Python。我试图通过取每个像素及其邻居的平均值来平滑图像的像素。我能够成功运行以下内容。

from cImage import *
import statistics as s


def smoothImg(oldimage):
    theWindow = ImageWin("Smooth Image",1200,1200)
    theImage = FileImage(oldimage)
    theImage.draw(theWindow)

    height = theImage.getHeight()
    width = theImage.getWidth()

    newImage = EmptyImage(width,height)

    for row in range(height):
        for col in range(width):
            try:
                pixelVal = theImage.getPixel(col-1,row-1)
            except:
                pixelVal = theImage.getPixel(col,row)  #maybe change to "pass"
            try:
                pixelVal2 = theImage.getPixel(col-1,row)
            except:
                pixelVal2 = theImage.getPixel(col,row)
            try:
                pixelVal3 = theImage.getPixel(col-1,row+1)
            except:
                pixelVal3 = theImage.getPixel(col,row)
            try:
                pixelVal4 = theImage.getPixel(col,row-1)
            except:
                pixelVal4 = theImage.getPixel(col,row)
            pixelVal5 = theImage.getPixel(col,row)
            try:
                pixelVal6 = theImage.getPixel(col,row+1)
            except:
                pixelVal6 = theImage.getPixel(col,row)
            try:
                pixelVal7 = theImage.getPixel(col+1,row-1)
            except:
                pixelVal7 = theImage.getPixel(col,row)
            try:
                pixelVal8 = theImage.getPixel(col+1,row+1)
            except:
                pixelVal8 = theImage.getPixel(col,row)
            try:
                pixelVal9 = theImage.getPixel(col+1,row)
            except:
                pixelVal9 = theImage.getPixel(col,row)

            redMean = s.mean([pixelVal[0],pixelVal2[0],pixelVal3[0],pixelVal4[0],pixelVal5[0],pixelVal6[0],pixelVal7[0],pixelVal8[0],pixelVal9[0]])
            greenMean = s.mean([pixelVal[1],pixelVal2[1],pixelVal3[1],pixelVal4[1],pixelVal5[1],pixelVal6[1],pixelVal7[1],pixelVal8[1],pixelVal9[1]])
            blueMean = s.mean([pixelVal[2],pixelVal2[2],pixelVal3[2],pixelVal4[2],pixelVal5[2],pixelVal6[2],pixelVal7[2],pixelVal8[2],pixelVal9[2]])

            meanPixel = Pixel(redMean,greenMean,blueMean)
            newImage.setPixel(col,row,meanPixel)


    newImage.setPosition(width+1,0)
    newImage.draw(theWindow)

    theWindow.exitOnClick()
    return

该程序似乎有效，但我无法想象这是最好的方法。此外，我希望能够采用更宽的像素平均值，而不仅仅是直接邻居。我尝试在for循环中运行此函数，但它只给了我一个完全灰色的图像。

def getMean(numPixels,image):
        pixelVals = []
        for row in range(numPixels):
            for col in range(numPixels):
                pixelVal = image.getPixel(col,row)
                pixelVals.append(pixelVal)
        redMean = int(s.mean([p[0] for p in pixelVals]))
        greenMean = int(s.mean([p[1] for p in pixelVals]))
        blueMean = int(s.mean([p[2] for p in pixelVals]))
        meanPixel = Pixel(redMean,greenMean,blueMean)
        return meanPixel

此问题取自＆＃34;上下文中的Python编程＆＃34;。第222页的练习6.25。