使用openCV以各个角度以各个角度之间的距离

Question

IM使用以下代码检测同心圆并以各个角度测量距离。外圆矩阵形状为零，im会出现错误 - 值：操作数不能与形状（0，）（2，）一起广播。请帮助解决错误。为您提供的图像参考

import cv2
import numpy as np
import shapely.geometry as shapgeo

# Read image, and binarize
img = cv2.imread('/Users/n/Opencv/New_OpenCv/image.jpeg', cv2.IMREAD_GRAYSCALE)
img = cv2.threshold(img, 128, 255, cv2.THRESH_BINARY)[1]

# Find (approximated) contours of inner and outer shape
cnts, hier = cv2.findContours(img, cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)
outer = [cv2.approxPolyDP(cnts[0], 0.1, True)]
inner = [cv2.approxPolyDP(cnts[2], 0.1, True)]

# Just for visualization purposes: Draw contours of inner and outer shape
h, w = img.shape[:2]
vis = np.zeros((h, w, 3), np.uint8)
cv2.drawContours(vis, outer, -1, (255, 0, 0), 1)
cv2.drawContours(vis, inner, -1, (0, 0, 255), 1)

# Squeeze contours for further processing
outer = np.vstack(outer).squeeze()
inner = np.vstack(inner).squeeze()

# Calculate centroid of inner contour
M = cv2.moments(inner)
cx = int(M['m10'] / M['m00'])
cy = int(M['m01'] / M['m00'])

# Calculate maximum needed radius for later line intersections
r_max = np.min([cx, w - cx, cy, h - cy])

# Set up angles (in degrees)
angles = np.arange(0, 360, 4)

# Initialize distances
dists = np.zeros_like(angles)

# Prepare calculating the intersections using Shapely
poly_outer = shapgeo.asLineString(outer)
poly_inner = shapgeo.asLineString(inner)

# Iterate angles and calculate distances between inner and outer shape
for i, angle in enumerate(angles):

    # Convert angle from degrees to radians
    angle = angle / 180 * np.pi

    # Calculate end points of line from centroid in angle's direction
    x = np.cos(angle) * r_max + cx
    y = np.sin(angle) * r_max + cy
    points = [(cx, cy), (x, y)]

    # Calculate intersections using Shapely
    poly_line = shapgeo.LineString(points)
    insec_outer = np.array(poly_outer.intersection(poly_line))
    insec_inner = np.array(poly_inner.intersection(poly_line))

    # Calculate distance between intersections using L2 norm
    dists[i] = np.linalg.norm(insec_outer - insec_inner)

    # Just for visualization purposes: Draw lines for some examples
    if (i == 10) or (i == 40) or (i == 75):

        # Line from centroid to end points
        cv2.line(vis, (cx, cy), (int(x), int(y)), (128, 128, 128), 1)

        # Line between both shapes
        cv2.line(vis,
                 (int(insec_inner[0]), int(insec_inner[1])),
                 (int(insec_outer[0]), int(insec_outer[1])), (0, 255, 0), 2)

        # Distance
        cv2.putText(vis, str(dists[i]), (int(x), int(y)),
                    cv2.FONT_HERSHEY_COMPLEX, 0.75, (0, 255, 0), 2)

# Output angles and distances
print(np.vstack([angles, dists]).T)
print(poly_outer)
print(poly_inner)
print(poly_line)
print(insec_inner)
print(insec_outer)
# Just for visualization purposes: Output image
cv2.imshow('Output', vis)
cv2.waitKey(0)
cv2.destroyAllWindows()