霍夫直线变换介绍 霍夫直线检测原理 通过直角坐标和极坐标的对应关系，在一条直线上的点所产生的sin曲线在极坐标区域会相交于同一个点（r, theta)，将这个（r,theta)对应到直角坐标就可以得到一条直线。
- HoughLines(image，rho，theta，threshold ，lines ，srn ，stn ，min_theta ，max_theta):
def line_detection(image): gray = cv.cvtColor(image, cv.COLOR_BGR2GRAY); edge = cv.Canny(gray, 50, 150, apertureSize = 3); lines = cv.HoughLines(edge, 1, np.pi/180, 150); #get pieces of (r,theta); for line in lines: rho, theta = line[0]; a = np.cos(theta); b = np.sin(theta); x0 = a * rho; y0 = b * rho; x1 = int(x0 + 1000 * (-b)); #必须乘1000 y1 = int(y0 + 1000 * (a) ); x2 = int(x0 - 1000 * (-b)); y2 = int(y0 - 1000 * (a) ); cv.line(image, (x1, y1), (x2, y2), (0, 0, 255), 2); cv.imshow("image_line", image); HoughLinesP( image, rho, theta, threshold, lines, minLineLength, maxLineGap) def line_detect_possible_demo(image): gray = cv.cvtColor(image, cv.COLOR_BGR2GRAY); edge = cv.Canny(gray, 50, 150, apertureSize = 3); lines = cv.HoughLinesP(edge, 1, np.pi/180, 200, minLineLength = 50, maxLineGap =10); #minLineLength, maxLineGap for line in lines: print(type(line)); x1, y1, x2, y2 = line[0];#line这个东西本来就只有一行!!!! cv.line(image, (x1, y1), (x2, y2), (0, 0, 255), 2); cv.imshow("line_detect_possible_demo", image);