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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HOG descriptor for pedestrian detection training

I wonder why my HOG descriptor can't prevail the right silhouettes of the human body. I use the parameters like CV_WRAP HOGDescriptor() : winSize(64,128), blockSize(16,16), blockStride(8,8), cellSize(8,8), nbins(9), derivAperture(1),…
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As number of detected SURF keypoints is different for each image, how to save in featurevector of fixed length?

The number of SURF keypoints is different for each image. I'm storing the features for each image in different columns as FV(N X K)=[FV_IMG1 FV_IMG2] I tried limiting 10 best features. But ofcourse some image have below 10 features. How to deal…
h612
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compare shapes of features in 2 images (matlab computer vision)

I'm trying to compare two images by features detection. The main goal is to find out if the two pictures are similar or not and if they are not I'll skip to the next model and compare those two until I'll found the one who is most similar. I've…
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Create a feature vector to classify segments in air images

I am working on a project to segment air images and classify each segment. The images are very large and have huge homogeneous areas, so I decided to use a Split and Merge Algorithm for the segmentation. (On the left the original image and on the…
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Bayesian inference in feature-based categorization

Here is my problem which I hope you can help me with: Lets say we live in a world where there are only two categories, where each has some features. The objects in this world are different permutations of these features. cat1: {a, b, c, d, e,…
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What is the best way to find SURF-features only on changed areas of frame?

For example, I calculate SURF descriptors for frames from real-time 50 fps FullHD video by using GPU: gpu::SURF_GPU But it is slow, and I can't calculate it for each frame, only for 10 fps. Video camera is stationary and fixed, so I can use the…
Alex
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OpenCV in C++ - Calculation of the L Band Power of an Image

I have to create a fire-detection program using OpenCV and C++ following an alghoritm from a scientific paper (see image below). At a certain point I have to calculate the "L band power" but I don't know what exacly it means. Can you help me? Image…
Jack
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Image detection: locate specific parts of image by colors/shape

I'm trying to figure out how i can detect parts of an image based on color and/or shape. Ideally what i want to achieve is that: given a lot of pictures which are similar in some way they always contain several identical but a non-trivial shape…
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How to stack Autoencoder/ Create Deep Autoencoder with Theano class

I understand the concept behind Stacked/ Deep Autoencoders and therefore want to implement it with the following code of a single-layer de-noising Autoencoder. Theano also provides a tutorial for a Stacked Autoencoder but this is trained in a…
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Detecting “Tablet/Touch Mode” in Edge using JavaScript on Windows 10?

This question was asked before, but the answers are not exactly what I need. I need to distinguish in Microsoft Edge if it's a tablet or not (Desktop). 1) The following thread: Can you detect "Tablet Mode" in Edge and IE11 using JavaScript on…
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Performace comparison between GLCM and LIRE for image matching

I want to create an image matching application. When I searched for it, I found two good approaches. 1) LIRE - Lucene Image Retrieval can be used to perform the image matching , where it implements various image matching algorithms and and also…
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feature detection: translateZ

how can i find out if a browser supports translateZ or not? i tried this one but it doesnt work... https://gist.github.com/lorenzopolidori/3794226 i only changed translate3D to translateZ, a short codepen example…
Gregor Voinov
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OpenCV: what is the difference between feature2d and imgproc feature detection algorithms?

Both imgproc and feature2d modules of OpenCV have feature detection, however I did not see anywhere any text explaining the difference between the two and why there are two distinct parts of OpenCV bearing the same name. Please, could anybody shed…
deb0ch
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javascript feature detect IE tracking protection

Soundcloud does not support < IE11, apparently because of IE9 + IE10's tracking protection. Is there an easy way in javascript to feature detect that tracking protection is set? I need to mask out all IEs with tracking protection, and I would really…
hasse
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Processing line scanner data

I have a line scanner output that is scanning the geometry of a surface. Typically the output looks something like this: Where the x and y axis refers to the coordinate system in mm. (ignore the red dots). This data is essentially a 2d point…
John Tan
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