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 is a process in computer vision that aims to find visual features within the image with particular desirable properties.

Detected features are some subsection of the image, and can be:

  • points (e.g. Harris corners)
  • connected image regions (e.g. DoG or MSER regions)
  • continuous curves in the image

Interesting properties can include invariance to noise, perspective transformations and viewpoint changes (camera translation and rotation), scaling (for use in visual feature matching), or properties interesting for specific usages (e.g. visual tracking).

Important information about visual features can include:

  • coordinates in the image
  • radius of the visual feature
  • scale (octave) of the image on which the feature has been extracted

After detecting the feature with some feature detection algorithm, it is usually described by a descriptor vector (several known descriptors are used today) for the purposes of visual feature matching, while the feature's position in the image can be used directly for application in tracking.

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Showing customer care feature only Mobile view and scroll bar in bottom of the page

I'm trying to show the Customer Care Feature(Email, Contact, and Call)on Mobile view and scrollbar in the bottom of the page. For this, I tried below code but not get success. Sometimes it's working and sometimes not. My Code is:
Bojjaiah
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What exactly can @supports test for (or not)?

What counts as a valid "feature query" for the purposes of @supports? I've been experimenting and so far it doesn't support (incorrectly returns false) many supported features in 2018…
Foo Bar
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What is the best feature detection?

We have two images, one as a reference and another image which we want to align like the reference using Matlab. In order to do this, we need to find similar points in both images and than calculate the kernel matrix using the Least Square method…
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How is a filter assigned with feature in CNN? (or is it assigned?)

Lets say the first conv layer has 32 filters of size 5x5 with stride of 1. model.add(Conv2D(32, (5, 5), input_shape=input_shape)) Lets say the image is of size 32x32x3(channesl). So when a filter convolves with a part of an image, is it already…
aztec242
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image feature identification

I am looking for a solution to do the following: ( the focus of my question is step 2. ) a picture of a house including the front yard extract information from the picture like the dimensions and location of the house, trees, sidewalk, and car.…
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Python image analysis - Check whether picture matches video frames

I have a problem, not so easy to solve i guess. In general, I have a database of frames from different videos and I want to find for a given picture (which is not necessarily one of the frames but from some same source video) the matching source…
acensored
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Compute FAST features - openCV Python

I am using openCV 3.1.0 in Python 2.7. I have successfully detected keypoints using the FAST detector. Now I would like to compute the features for each of these points using the FAST.compute() method. However I did not manage to have this function…
Jindil
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How to display the data as augmented only if the user is facing towards a feature in the real world?

I am currently developing an augmented reality android application in which I would like to display the discharge data of a river along with the river name as augmented features. However, I would like to show the data augmented only if an user is…
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How to check if a point is inside a set of contours

Hello to everyone. The above image is sum of two images in which i did feature matching and draw all matching points. I also found the contours of the pcb parts in the first image (half left image-3 contours). The question is, how could i draw only…
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Is there a pre-existing haarcascade .xml file for frown detection which can be used to detect whether a person is frowning or sad?

I wish to use it with Opencv in python. I know that i could create a custom cascade classifier, but i don't have time to do that. Is there a better or faster way to do this?? Any help would be appreciated
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how to reduce dimension of image feature vector(560 dimensions) for elasticsearch

I am working on an image search engine. I use an algorithm to extract features from images and get a 560 dimensions float vector. This dimension is too high for elasticsearch to index, es will be very slow. So I want to reduce dimensions of feature…
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Checking if an color is similar to another

I have an Java program that checks on an image if each pixel has his color similar to an target. Up to the point to get each pixel, nothing wrong, but the things get hard when I need to check, with an error margin, if the color of the pixel is…
Taarak
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Real time logo detection in live camera preview with OpenCV on Android

I am new to computer vision but I am trying to code an android app which does the following: Get the live camera preview and try to detect one logo in that (i have the logo in my resources). In real-time. Draw a rect around the logo if found. If…
marco56
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OpenCV Dense SIFT block size

I know from other posts that I can extract dense features from image with following code(python): dense=cv2.FeatureDetector_create("Dense") kp=dense.detect(imgGray) kp,des=sift.compute(imgGray,kp) Say, I'd like to have the block size of SIFT…
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How to define feature type through program argument in opencv?

Currently changing feature type is done by changing the name manually in the code. For example, for SURF detector and descriptor, I have to change the word "SURF" to some other name in the following code sample: Ptr detector =…
SK90
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