p.pt for p in kp]
时间: 2024-05-27 13:11:39 浏览: 6
This is a list comprehension in Python that generates a new list containing the result of calling the method "pt" on each element "p" in the original list "kp".
Assuming that "kp" is a list of objects with a method called "pt", this list comprehension will apply the "pt" method to each object in the list and return a new list with the results.
For example, if "kp" is a list of Point objects (where each Point object has a "pt" method that returns the coordinates of the point), this list comprehension would generate a new list containing the coordinates of each point in "kp".
相关问题
kp = np.array([p.pt for p in kp]).T
This line of code takes a list of key points 'kp' and converts them into a numpy array.
The key points are objects that contain information about the location and other properties of a feature detected in an image. In this case, the 'pt' attribute of each key point is being extracted, which represents the (x,y) coordinates of the feature.
The 'np.array' method is used to convert the list of (x,y) coordinates into a numpy array. The '.T' at the end transposes the array (switches the rows and columns), so that it is in the right format for further processing.
Overall, this line of code is useful for organizing and manipulating the key point data for further use in computer vision tasks such as feature matching and object recognition.
kp, desc = sift.detectAndCompute(img_gray, None) kp = np.array([p.pt for p in kp]).T
The first line of code detects and computes SIFT (Scale-Invariant Feature Transform) keypoints and descriptors from the grayscale image "img_gray".
The second line of code extracts the keypoint locations from the "kp" variable and stores them as a numpy array. The ".pt" attribute of each keypoint object represents the (x,y) coordinates of the keypoint.
Finally, the ".T" method transposes the numpy array so that each row represents a single keypoint location, with the first row containing all the x-coordinates and the second row containing all the y-coordinates.