python - opencv simpleblobdetector - 获取已识别 blob 的 blob 属性

Question

我正在使用 opencv 中的 simpleblobdetector 和 python 来识别图像中的 Blob 。

我能够让简单的 Blob 检测器工作，并为我提供已识别 Blob 的位置。但是我也可以得到已识别 Blob 的惯性/凸性/圆度/等属性吗？

img = cv2.imread('image.png', cv2.IMREAD_GRAYSCALE)

# set up blob detector params
detector_params = cv2.SimpleBlobDetector_Params()
detector_params.filterByInertia = True
detector_params.minInertiaRatio = 0.001
detector_params.filterByArea = True
detector_params.maxArea = 10000000
detector_params.minArea = 1000
detector_params.filterByCircularity = True
detector_params.minCircularity = 0.0001
detector_params.filterByConvexity = True
detector_params.minConvexity = 0.01

detector = cv2.SimpleBlobDetector_create(detector_params)

# Detect blobs.
keypoints = detector.detect(img)

# print properties of identified blobs
for p in keypoints:
    print(p.pt) # locations of blobs
    # circularity???
    # inertia???
    # area???
    # convexity???
    # etc...

谢谢

Answer 1

根据 opencv.org，检测器返回的关键点不包含有关找到它们的算法的任何信息:

cv::KeyPoint: Data structure for salient point detectors.

The class instance stores a keypoint, i.e. a point feature found byone of many available keypoint detectors, such as Harris cornerdetector, cv::FAST, cv::StarDetector, cv::SURF, cv::SIFT,cv::LDetector etc.

The keypoint is characterized by the 2D position, scale (proportionalto the diameter of the neighborhood that needs to be taken intoaccount), orientation and some other parameters.

您可以绘制关键点，显示大小和旋转:

img = cv2.drawKeypoints(img, keypoints, None, color=(0,255,0), flags=cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS)