Questions tagged [feature-detection]
Feature detection is a process in computer vision that aims to find visual features within the image with particular desirable properties. Detected features can be points, image regions or continuous curves in the image. Interesting properties can include invariance to noise, perspective transformations, or properties interesting for specific usages (e.g. tracking).
feature-detection
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How to calculate the angular velocity of a rotating cell from a microbe video?
I have a video of Brownian motion of microbes under a microscope. From this video, I need to calculate the angular velocity of a particular prominent cell. From my understanding, what I know is that I ...
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Why does flann.knnMatch() give empty pair?
I am trying to use flann.knnMatch() from opencv to find feature matches, but sometimes there are some empty pair(closest and second closest neighbors) in the return list. Does anyone know what might ...
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Detecting center and radius of craters in microscopy images
I want to find the center and the radius of crater-like features in microscopy images using Python.
I have images like this, they are numpy arrays representing the height map of a surface.
I need the ...
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Image preparation before SIFT extracting features, or how to make SIFT work stable
I have a set of satellite images (which I'm going to index using SIFT) and there are also images from another source (drone)
I extract the features from image made by the drone and try to find similar ...
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Python open-cv find lines in noisy image
I want to find the dark gray diagonal line in this
the background is quite noisy and has a gradient in brightness.
(The line is barely visible when opening the .png but if I read it as grayscale the ...
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Separating Bad Matches vs Good matches in Template Matching, especially with Overlapping images (OpenCV)
I'm trying to find and identify agent/character icons in an image for a project (specifically the agent icons that are outlined with a green border). I only began learning OpenCV a month ago, and the ...
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How to Stitch Two Images with a Black Background and Different Sizes Using OpenCV, Python
I tried creating a program to stitch together multiple drone captured images. However, the program can only stitch two images at a time. So, I decided to stitch them in pairs, using the previously ...
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goodFeaturesToTrack to obtain point correspondences between images
I have an image sequence (example KITTI). I want to obtain the motion between frames (up to scale. i.e, translation vector norm is 1.).
I could find ORB features, in both images, calculate their ...
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How to detect if browser supports "Add to Homescreen" on iOS
In iOS, Safari is the only browser with the "Add to Homescreen" feature. I want to show instructions to the user how to use this feature, but only if this feature exists. Is there a way to ...
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How to detect if page doesn't allow to run external script via Content Security Policy? [duplicate]
I have a bookmark (Scheme REPL) and it doesn't work on the same pages because of Content Security Policy. But the error is in the console:
Example from GitHub:
VM70:1 Refused to load the script '...
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Automatically Determine Best Filter Values for Feature Matching
I am using SIFT to match features between two videos. I would like my HSV/CannyEdge filter trackbar GUI to automatically adjust parameters based on what will result in optimal feature-matching results....
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Which Feature Selection Techniques for NLP is this represent
I have a dataset that came from NLP for technical documents
my dataset has 60,000 records
There are 30,000 features in the dataset
and the value is the number of repetitions that word/feature appeared
...
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slice a scrabble board?
I'm working on a project that requires me to get information(letters present) from a scrabble game board.
EDIT: I must get the position of the letters too
For now I successfully detected the board ...
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Which feature detection algorithm does cv2.Stitcher() use?
I just learnt about SIFT, ORB & SURF algorithms and how they are used for feature detection & extraction, and Homography & RANSAC techniques used in Image Fusion. While SIFT & SURF ...
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Finding index of feature matching points in Python openCV2
full code :
import cv2, numpy as np
img1 = cv2.imread('img1.jpg')
img2 = cv2.imread('img2.jpg')
gray1 = cv2.cvtColor(img1, cv2.COLOR_BGR2GRAY)
gray2 = cv2.cvtColor(img2, cv2.COLOR_BGR2GRAY)
# ORB, ...
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