在OpenCV中修正失真的裁剪图像(Python)

Question

我一直在寻找其他帖子的回复,并尝试了几种方法来获得它,但我找不到任何解决我的问题.我正在尝试纠正图像中的光学失真并得到它,但现在我想裁剪我的图像以删除结果图像中的弯曲黑色边框.总而言之,这是我的问题:

我想像这样裁剪:

我尝试使用以下代码进行裁剪:

h,  w = corrected_img.shape[:2]
newcameramtx, roi = cv2.getOptimalNewCameraMatrix(cameraMTX,distortionCoeffs,(w,h),1,(w,h))
x,y,w,h = roi
desired_result = corrected_img[y:y+h, x:x+w]

但不幸的是,roi总是占据这个价值(0,0,0,0).

谁能帮助我？

提前致谢.

Answer 1

由于空白部分在图像中间具有最大值/最小值,因此您可以查找中间线并查看颜色何时发生变化.下图可能会澄清这一点:

你只需要找到x1,y1,x2和y2图所示.这可以按如下方式完成:

import cv2
# Reads the image in grayscale
img = cv2.imread('Undistorted.jpg', 0)
h, w = img.shape
x1, x2, y1, y2 = (0,0,0,0)

# Color threshold of the void part
void_th = 10

# List of colors in the vertical an horizontal lines that cross the image in the middle
vertical = [img[i, int(w/2)] for i in range(h)]
horizontal = [img[int(h/2), i] for i in range(w)]

# Reverses both lists
vertical_rev = vertical[::-1]
horizontal_rev = horizontal[::-1]

# Looks when the change of color is done
for i in range(2,h):
    if vertical[i] > void_th and y1 == 0:
        y1 = i
    if vertical_rev[i] > void_th and y2 == 0:
        y2 = i
    if y1 != 0 and y2 != 0:
        break
for i in range(2,w):
    if horizontal[i] > void_th and x1 == 0:
        x1 = i
    if horizontal_rev[i] > void_th and x2 == 0:
        x2 = i
    if x1 != 0 and x2 != 0:
        break

desired_result = img[y1:h-y2, x1:w-x2]
cv2.imshow('Crop', desired_result)

我所做的是中间行中的像素颜色列表,然后循环它们直到颜色高于阈值(0是黑色,255是白色).当检测到第一个颜色变化的像素时,存储位置并且循环中断.输出是裁剪后的图像:

注意:由于边界线,我从位置2开始循环,原始图像不需要.

希望这有帮助!