904 questions
4
votes
0
answers
105
views
OpenCV feature matching for low contrast images
First time post here!
I'm having difficulty in trying to feature match with the attached images.
Generally I've been successful with other images with SIFT. The relevant code is below. You can see the ...
- 41
2
votes
2
answers
316
views
Circle fitting with points inside the circle
I have a noisy binarized image, in which most white points lay within a circle. What would be a good algorithm to fit the circle? The algorithm should be robust to handle all sorts of defects in the ...
- 1,829
0
votes
0
answers
48
views
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 ...
2
votes
2
answers
131
views
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 ...
- 1,215
1
vote
0
answers
139
views
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 ...
- 31
3
votes
1
answer
351
views
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 ...
- 33
0
votes
0
answers
105
views
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 ...
- 1
1
vote
0
answers
494
views
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 ...
- 11
0
votes
0
answers
407
views
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 ...
- 11
0
votes
1
answer
469
views
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 ...
- 2,267
1
vote
0
answers
37
views
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 '...
- 67.1k
0
votes
0
answers
76
views
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....
-1
votes
1
answer
76
views
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
...
- 8,150
1
vote
0
answers
70
views
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 ...
- 79
2
votes
1
answer
1k
views
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 ...
- 145
1
vote
0
answers
324
views
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, ...
- 13
2
votes
1
answer
304
views
Feature matching between segmented images
I would like to improve the feature matching between two images by using a pre-trained semantic segmentation model. Of course I am familiar with the ORB or SIFT features and matching with OpenCV in ...
- 59
1
vote
1
answer
382
views
OpenCV asynchronous ORB feature detection function is blocking on the CPU
I've been trying to get OpenCV ORB feature detection working asynchronously on the GPU, however I'm not getting the results I expect when timing the different function calls. The function ...
- 211
-1
votes
1
answer
687
views
How to select the best features from all features when data sets don't have target variable where feature importance can change over time?
My data sets have 200 features and 500 rows. from that I must select the best 30 features that can be used in the model instead of all 200 features for the sales prediction model, but the feature ...
- 375
1
vote
1
answer
60
views
applying MSDDetector in colab
I have trouble writing the MSD detector correctly. However, it has no attribute ''create''.
I wrote the following code. But my session crashed for an unknown reason.
msd=cv2.xfeatures2d.MSDDetector()
...
0
votes
1
answer
478
views
Feature Extraction - How to ONLY Detect SIFT Feautures OUTSIDE Region of Interest?
I understand that it is possible to exclusively extract features INSIDE a ROI by providing a mask to the sift feature detector. I am wondering if it is possible to exclusively extract SIFT features ...
-1
votes
1
answer
574
views
How can I improve the quality of the recognition of playing cards?
I am trying to build a classification of playing cards. The goal is that I use an image of a playing card as input and the script then outputs whether it is a playing card and if so, which one.
For ...
- 59
4
votes
2
answers
716
views
Stitching computer images by feature without warping (no camera images)
I've did quite a search about image stitching on python and most are for panoramic images, warping and rotating the images to combine them into one.
What I'm trying to do is using computer images, so ...
- 1,050
2
votes
1
answer
422
views
Detecting a very indistinct triangle on a dial using OpenCV
So I have a temperature box where I am trying to pinpoint the coordinate location of a small triangle on each temperature dial. Here are the examples of the box with slight variations:
[
I have been ...
- 23
1
vote
0
answers
36
views
Scikit Learn/Numpy- Tell between a linear path and an anomaly (non-linear) path?
I have an array of lat/lon/time data for an airplane track inside a numpy array:
array([[29.2205, -97.0371, 21373410],
[29.2554, -97.0201, 21373439],
[29.2993, -97.0178, 21373469],
[...]])
...
- 56
0
votes
0
answers
80
views
Clustering error while using BOW to get the vocabulary of the images
void SceneRecognition::BowRepresentation()
{
Mat dstGray2;
//Folder path is written and file names are taken according to that.
vector <String> fileNames;
String folder("...
0
votes
0
answers
167
views
Why does SIFT create an image pyramid?
My understanding is that SIFT is made scale invariant by using different scales for the gaussian smoothing, why is an image pyramid also used?
- 601
1
vote
0
answers
41
views
Optically detect specific characters in a text document
We try to detect certain rare characters when doing OCR of scans of old documents.
What is the state-of-the-art approach to text-object detection in document image analysis and OCR? Are standard SURF ...
- 63
0
votes
1
answer
964
views
Using Keypoint feature matching + Homography to straighten document (Aadhaar)
Hi I'm trying to create an OCR where the model should be able to read an uploaded document. However, lot of times, the documents uploaded are skewed or tilted. I plan to straighten and/or resize the ...
1
vote
0
answers
558
views
Find shift and rotation of image by comparing and finding location of maximum feature in image
I am trying to solve two problems.
I have two same image one as it is and other as some rotation and shift in it. I tried using phase correlation for finding the shift on image and it works fine. But ...
- 49
0
votes
1
answer
77
views
How does Infragistics determine what features a browser supports?
With Chrome 100 on the horizon, this has become a concern for us. How does Infragistics determine what features a browser supports?
Do they query the user agent string, and query the browser name?
Do ...
- 17.1k
2
votes
0
answers
913
views
Detect overlapping circles (spheres) with shadows with OpenCV and Python
I am writing a program with OpenCV that detects circles in the structure pictures. I'm using the Watershed method described here.
There is a problem I faced: 3d structure photo is hardly converted ...
0
votes
0
answers
258
views
What is the formula to calculate repeatability score for feature detector-descriptors
With reference to the paper "Performance Evaluation of Feature Detectors and Descriptors Beyond the Visible", there is a paragraph that explains how the repeatability score is calculated, ...
- 49
7
votes
0
answers
1k
views
Meaning of algorithm, trees, and checks during Flann based feature matching (OpenCV, python)
I am currently testing Flann feature matching with OpenCV in python, and do not fully understand what some of the parameters actually do. Here is a snippet of code copied from the OpenCV docs. The ...
0
votes
1
answer
300
views
How to isolate the bars with cv2?
How do I isolate the bars with no white fill, in the image below that represents a bar chart?
I'm looking for a solution which will work for any variation of this image. You can assume that the format ...
- 14.8k
2
votes
1
answer
2k
views
(-215:Assertion failed) while drawing matches in opencv
I'm currently following this article: https://docs.opencv.org/4.5.2/dc/dc3/tutorial_py_matcher.html
When drawing the matches I get the following error:
error: (-215:Assertion failed) i1 >= 0 &&...
- 23
2
votes
0
answers
102
views
In ARKit, Can I select any real world object to bind virtual objects with it, using depth map or other techniques?
I am wondering how to implement this in ARKit: I have a bottle on the table and I want to add a "small hat" on it, by circling the aimed object like I did with red pen in the pic.
enter ...
- 21
0
votes
1
answer
302
views
How to find optical flow only inside bounding box?
I'm using the Lucas-Kanade sparse optical flow method where I'm finding feature points using the Shi-Tomasi corner detector Good Features to Track.
How do I detect feature points only inside the ...
3
votes
0
answers
2k
views
OpenCV Good Features to Track how to set quality measure?
The Shi-Tomasi Corner Detector in python OpenCV looks like this:
feature_params = dict(maxCorners=100, qualityLevel=0.3, minDistance=7, blockSize=7)
p0 = cv2.goodFeaturesToTrack(frame, mask=None,...
1
vote
0
answers
453
views
How to compute descriptors for predefined keypoints correctly?
I want to develop a face alignment program. There is a video, from which the face is extracted and aligned. It is happening in the following way: there is a result frame, constructed from the first ...
- 956
0
votes
0
answers
127
views
How to create continuous line boundary on the image?
I just started working in the image processing field and got a problem. I hope somebody could suggest me the way to approach it.
Input: 1 image or a 3D stack of images.
Output: The same image or a ...
2
votes
0
answers
191
views
Matching certain features of CAD-File and 2D-images
whats the best way to start, for matching certain features of a CAD-File to 2D-images?
So basically it's about quality assurance in manufacturing:
There are CAD-files of an assembly, that show the ...
- 21
0
votes
0
answers
246
views
In ORB-SLAM, finding Translation vector that is coming out a random value
I am trying to find out the translation vector (basically pose estimation) between two consecutive images.
Here is what I did in OpenCV (.js):
Take input from the webcam
Get the consecutive images
...
1
vote
1
answer
2k
views
OpenCV Object detection with Feature Detection and Homography
I am trying to check if this image:
is contained inside images like this one:
I am using feature detection (SURF) and homography because template matching is not scale invariant. Sadly all the ...
- 962
0
votes
0
answers
269
views
Quality inspection python opencv object detection
We have a conveyor line it stops 4 seconds at the test system. What we need to do is detecting sticked logos; is the logo correctly sticked(logo sticked or no logo), do we have a quality defects like ...
1
vote
0
answers
171
views
How to detect secchi disk marker in the image?
What would be lightweight and reliable method to detect secchi disk in the image?
- 384
0
votes
1
answer
326
views
tagged hook does not work as expected. It runs always
I have two cucumber features. Only one of them is tagged by tag @maximize which maximizes the browser window. I have also the hooks class which contains one @Before hook which should run only for tag @...
- 4,413
2
votes
0
answers
244
views
How can I detect in Kotlin or Java whether the Android device supports MHL (HDMI)?
Some Android devices support HDMI via micro USB or USB C cables and adapters. Usually using MHL (Mobile High-Definition Link)
How can I check programmatically from my app whether the device it's ...
- 17.3k
1
vote
1
answer
73
views
How to find the same feature points within an image after print-scan process?
I'm trying to find the same feature points within an image, before and after the print-scan process. To do this, I used cv2.goodFeaturesToTrack method:
import numpy as np
import matplotlib.pyplot as ...
- 109
1
vote
0
answers
169
views
C++ std::streambuf::pubseekpos(): check if random access is supported
While writing a generic function taking a reference to an std::streambuf, I'd like to check if the supplied buffer is tied to something supporting random access or not and optimize the treatment ...
- 303