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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Real time feature matching with stereo camera

I have a stereo camera setup and I am trying to match features between the two frames so that I can triangulate the corresponding points into a 3d point cloud. It kind of works, using SURF, but is too slow for real-time use. Is there a faster way?…
anti
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Feature Detection Opencv/Javacv not working

I am trying to run the feature detection program of javacv to compare the similar features in 2 images however I am getting a runtimeexception. Since I am completely new to javacv I don't know how to resolve this. The exception trace is OpenCV…
Wanderer
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How to remove vertical lines from img

I have a problem to find digits in pictures attached bellow. It is caused by vertical lines which sometimes occur and sometimes it's not. I'm looking for idea how to remove these vertical lines them from pictures. I've tried contour detection, but…
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Why feature description is needed in image registration?

I'm trying to implement a feature based image registration algorithm. From my observation, description of each feature point (key point) is required before the matching operation. Is it mandatory to describe the features, if yes, why? Kindly help…
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Making a sinusoidal curve in an image into a straight line in the output image

I have to make a sinusoidal curve in an image to output an equal straight line in the resulting image. An example of input sinusoidal image: What I think is one solution should be: Placing down the origin of x and y coordinates at the start of the…
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Susan Corner Detector implementation

I have not understood the code and the way function is handled.. can you elaborate the function declaration fun = @(img) susanFun(img); map = nlfilter(img,maskSz,fun); Also in susan corner detector we have only 2 threshold values.. "t and…
John
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Implement Facial Feature Detection

I want to know how 'feature detection and extraction' works step by step. I refer to this Journal, you can download it here : http:// dynamics.org/~altenber/UH_ICS/EC_REFS/GP_REFS/CEC/2002/GP_WCCI_2002/7074.PDF Such as convert RGB to Grayscale, We…
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Which feature descriptors to use and why?

I do like to do compute the position and orientation of a camera in a civil aircraft cockpit. I do use LEDs as fixed points. My plan is to save their X,Y,Z Position associated with the LED. How can I detect and identify my LEDs on my images? Which…
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Can I use OpenCV to analyze image content?

I want to detect content of images. For example I want to use the above image as an input, and get as output list of terms like: sky, water, sea, buildings etc. Any idea how to start?
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