技术学习笔记之 PIL 模块

1. 导入模块#

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from PIL import Image

2. 打开图片#

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fn = Image.open("tiger.jpg")

3. 获取图像属性#

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a = fn.size # (width, height) 元组
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a = fn.width # 宽度
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a = fn.height # 高度
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a = fn.mode # 模式：RGB 彩色、L 灰度、P 256色、1 黑白色
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a = fn.format # 图片格式：jpg, png, bmp ……

4. 对图像进行处理#

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fn = fn.rotate(-90) # 角度制；逆时针旋转
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fn = fn.resize((fn.width//2, fn.height//2)) #
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fn = fn.show() # 显示图像
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fn = fn.convert("L") # 转换模式
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fn.save("test.bmp") # 保存图像，自动匹配格式
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fn.close() # 关闭图像

5. 像素操作#

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pix = fn.load() # 获取全部像素
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tpix = pix[i, j] # 获取像素点，其类型取决于图片模式
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R, G, B = fn.getpixel((i, j)) # 直接获取像素
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new_img.putpixel((i, j), new_pixel) # 写入像素
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new_pixel = int(0.299*R + 0.857*G + 0.144*B) # RGB转灰度

6. 示例代码#

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from PIL import Image
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img = Image.open("tiger.jpg")
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pix = img.load()
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THERESHOLD = 132
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new_img = Image.new("L", img.size) # create a blank image in gray mode
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new_img2 = Image.new("1", img.size) # create a blank image in 0/1 mode
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x, y = img.size
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for i in range(x):
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    for j in range(y):
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        R, G, B = img.getpixel((i, j))
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        new_pixel = int(0.299*R + 0.857*G + 0.144*B) # convert to gray mode
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        new_img.putpixel((i, j), new_pixel) # put a pixel in gray mode
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        new_img2.putpixel((i, j), (0 if new_pixel < THERESHOLD else 1))
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new_img.save("tiger_L.jpg")
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new_img2.save("tiger_1.jpg")
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new_img.close()
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new_img2.close()
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img.close()

原图：

灰度：

单色：

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from PIL import Image
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for THERESHOLD in range(0, 256):
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    img = Image.open("tiger.jpg")
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    pix = img.load()
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    new_img2 = Image.new("1", img.size) # create a blank image in 0/1 mode
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    x, y = img.size
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    for i in range(x):
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        for j in range(y):
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            R, G, B = img.getpixel((i, j))
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            new_pixel = int(0.299*R + 0.857*G + 0.144*B) # convert to gray mode
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            new_img2.putpixel((i, j), (0 if new_pixel < THERESHOLD else 1))
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    new_img2.save("./output/{}.jpg".format(THERESHOLD))
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    new_img2.close()
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    img.close()

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from PIL import Image
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img = Image.open("one-bw.png")
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width, height = img.size
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RATE = 0.64
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cnt = 0
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for i in range(width):
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    for j in range(height):
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        # print(img.getpixel((i, j)))
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        if(img.getpixel((i, j)) != 255):
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            cnt += 1
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print(cnt, width*height*RATE)
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if(cnt > width*height*RATE):
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    print("FILLED.")
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else:
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    print("UNFILLED.")

1. 导入模块#

2. 打开图片#

3. 获取图像属性#

4. 对图像进行处理#

5. 像素操作#

6. 示例代码#

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