使用PIL过滤部分图像

Question

如何使用 PIL 将模糊滤镜应用到图像的一部分？

Answer 1

您可以裁剪图像的一部分，对其进行模糊处理，然后将其粘回原处。如下所示：

box = (30, 30, 110, 110)
ic = image.crop(box)
for i in range(10):  # with the BLUR filter, you can blur a few times to get the effect you're seeking
    ic = ic.filter(ImageFilter.BLUR)
image.paste(ic, box)

下面是我用来生成棋盘、保存图像等的完整代码。（这不是生成棋盘等最有效的方法，这只是为了演示。）

import Image, ImageDraw, ImageFilter
from itertools import cycle

def draw_chessboard(n=8, pixel_width=200):
    "Draw an n x n chessboard using PIL."
    def sq_start(i):
        "Return the x/y start coord of the square at column/row i."
        return i * pixel_width / n

    def square(i, j):
        "Return the square corners, suitable for use in PIL drawings" 
        return map(sq_start, [i, j, i + 1, j + 1])

    image = Image.new("L", (pixel_width, pixel_width))
    draw_square = ImageDraw.Draw(image).rectangle
    squares = (square(i, j)
               for i_start, j in zip(cycle((0, 1)), range(n))
               for i in range(i_start, n, 2))
    for sq in squares:
        draw_square(sq, fill='white')
    image.save("chessboard-pil.png")
    return image

image = draw_chessboard()

box = (30, 30, 110, 110)

ic = image.crop(box)

for i in range(10):
    ic = ic.filter(ImageFilter.BLUR)

image.paste(ic, box)

image.save("blurred.png")
image.show()

if __name__ == "__main__":
    draw_chessboard()

Answer 2

我只是添加@tom10 发布的上述答案。

# importing PILLOW library.
from PIL import Image, ImageFilter

image = Image.open('path/to/image_file')
box = (30, 30, 110, 110)
crop_img = image.crop(box)
# Use GaussianBlur directly to blur the image 10 times. 
blur_image = crop_img.filter(ImageFilter.GaussianBlur(radius=10))
image.paste(blur_image, box)
image.save('path/to/save_image_file')

我刚刚将 ImageFilter.Blur 替换为 ImageFilter.GaussianBlur(radius=10)。您可以通过更改半径值来更改模糊量。