Question

使用以下代码（我在另一个stackoverflow帖子中找到，并且不是我的），我试图在掩码的帮助下从图像复制多边形区域。我不太熟悉python的numpy数组，并且很难搞清楚如何在这里创建透明蒙版。目前，代码生成黑色（＃000000）掩码。我已经尝试过使用Python Wand的一些后期图像处理，但结果是不可取的。

编辑：这是原帖：NumPy/OpenCV 2: how do I crop non-rectangular region?

这是我的python魔杖代码：

from wand.image import Image
from wand.color import Color
from wand.drawing import Drawing
from wand.compat import nested

with Image(filename="image_masked.png") as img:
    img.format = "png"
    with Color("#000000") as black:
        twenty_percent = int(65535*0.2) # Note: percent must be calculated from Quantum
        img.transparent_color(black, alpha=0.0, fuzz=twenty_percent)
        img.save(filename="transparent.png")

这是原始代码：

import cv2
import numpy as np

# original image
# -1 loads as-is so if it will be 3 or 4 channel as the original
image = cv2.imread('input_image.jpg', -1)
# mask defaulting to black for 3-channel and transparent for 4-channel
# (of course replace corners with yours)
mask = np.zeros(image.shape, dtype=np.uint8)
roi_corners = np.array([[(2320,330), (0,90), (0,450), (0,550)]],dtype=np.int32)
# fill the ROI so it doesn't get wiped out when the mask is applied
channel_count = image.shape[2]  # i.e. 3 or 4 depending on your image
ignore_mask_color = (255,)*channel_count
cv2.fillPoly(mask, roi_corners, ignore_mask_color)

# apply the mask
masked_image = cv2.bitwise_and(image, mask)

# save the result
cv2.imwrite('image_masked.png', masked_image)
cv2.imshow('image',masked_image)
cv2.waitKey(0)
cv2.destroyAllWindows()

用numpy创建透明蒙版

0 个答案: