Menu
When finding the center coordinates using moments in OpenCV,the point is found using
Point(moment[i].m10/moment[i].m00,moment[i].m01/moment[i].m00);
Can somebody please explain this bit to me?What do "m10","m00","m01" and "m00" mean??
609
In image processing, computer vision and related fields, an image moment is a certain particular weighted average (moment) of the image pixels' intensities, or a function of such moments, usually chosen to have some attractive property or interpretation. Image moments are useful to describe objects after segmentation.
Hu Moments ( or rather Hu moment invariants ) are a set of 7 numbers calculated using central moments that are invariant to image transformations. The first 6 moments have been proved to be invariant to translation, scale, and rotation, and reflection. While the 7th moment's sign changes for image reflection.
Output: We see that there are three essential arguments in cv2. findContours() function. First one is source image, second is contour retrieval mode, third is contour approximation method and it outputs the image, contours, and hierarchy. 'contours' is a Python list of all the contours in the image.
Working of approxPolyDP() function in OpenCV We make use of a function in OpenCV called approxPolyDP() function to perform an approximation of a shape of a contour. The image of a polygon whose shape of a contour must be approximated is read using the imread() function.
Definition of moments in image processing is borrowed from physics. Assume that each pixel in image has weight that is equal to its intensity. Then the point you defined is centroid (a.k.a. center of mass) of image.
Assume that I(x,y) is the intensity of pixel (x,y) in image. Then m(i,j) is the sum for all possible x and y of: I(x,y) * (x^i) * (y^j).
Here you can read the documentation of moments used in OpenCV. They are called raw moments.
And here you can read a wiki article about all kinds of image moments (raw moments, central moments, scale/rotation invariant moments and so on). It is pretty good one and I recommend reading it.
150
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
