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Questions tagged [viola-jones]

The Viola–Jones object detection framework is the first object detection framework to provide competitive object detection rates in real-time proposed in 2001 by Paul Viola and Michael Jones.

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How to edit "mexopt.bat" file in Matlab?

I have Matlab R2014b and OpenCV 2.4, i have been trying to use ViolaJones Face Detection toolbox, but i have some troubles. I've searhced the problem and found a solution that suggest edit mexopt.bat file. What the real problem is here The Matlab…
Burak Arık
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Viola-Jones - what does the 24x24 window mean?

I'm learning about the Viola-James detection framework and I read that it uses a 24x24 base detection window[1][2]. I'm having problems understanding this base detection window. Let's say I have an image of size 1280x960 pixels and 3 people in it.…
Mateo Velenik
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Viola jones face detection...how to use tilted features from open-cv haar cascades

I am trying to understand the VIOLA JONES algorithm and I came across an implementation in MATLAB which uses the open-cv haarcascade. It worked well for face detection (using haarcascade_frontalface_alt.xml), but when used with other classifiers…
Amit Raj
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Efficiently integrate detection results

In Viola and Jones's paper, section 5.6 the authors mention they integrate multiple detections their detector make while scanning for faces in images. In this case, a detection is simply a rectangular region positioned over an image where the…
Ramiro
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Threshold values for viola jones object detection

I am trying to perform Adaboost training stated by Viola and Jones in their paper on rapid object detection. However, I do not understand how to get the threshold values that will classify the faces from non faces for each of the 160k features. Is…
medz91
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Real time face detection in MATLAB

I'm trying to make a real time face detector using MATLAB. I found a sample code on the Mathworks' page, but it uses a sample video. What I'm having a problem with it that this code only can track the one it chooses to even with a few faces in the…
Martin V
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Fastest Python way to evaluate haar feature values

Hi I am new to python and implementing Viola-Jones face detection algorithm using python. While haar-feature selection using Adaboost, my code is taking extreme time (near about 18 hours) to select one haar-feature in each round of boosting. Somehow…
user2766019
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How to use Haar Feature results in Viola Jones Face Detection Algorithm

I am trying to understand the Viola-jones Face detection algorithm. In paper they have mentioned that there can be 160k plus haar features in a 24x24 pxiels image. I am struggling in understanding how to determine the weak classifier. For example…
user2793078
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How to read OpenCV's haarcascade_frontalface_default.xml file without OpenCV in Python?

I'm trying to implement Viola-Jones algorithm from scratch in Python. However, I do not want to waste a lot of time training. So, I was thinking about using the haarcascade_frontalface_default.xml file to get the classifiers immediately. However,…
ahmedmoh123
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Adaboost classifier for face detection using viola jones algorithm

I'm trying to implement this algorithm, and currently confused at the part for selecting the best classifier. In this part, I'm supposed to select the best polarity and threshold for each feature, but I don't know from where I should choose the…
The Beef
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threshold to determine Haar Feature

I try now to understand the Viola-Jones algorithm and I get confused about the threshold to determine if a block a Haar feature or not. The intensity of a pixel is in the range of 0->255. When we have an ideal Haar feature then the delta value is…
actnmk
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Viola-Jones face detection and features per weak classifeirs

From what I've read, each weak classifier in Viola-Jones face detection gets all N training samples and only 1 feature. 1) Does that mean that I will have to check over 160k classifiers at first for 24x24 frame, since there are that many Haar…
qalis
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How should I implement the cascade of classifiers in Viola-Jones algorithm on FPGA?

I am trying to implement the Viola-Jones algorithm on FPGA. I am not sure what I should do about the cascade of classifiers. How should I implement it on the FPGA?
Roxana_A
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How is the ROC curve plotted in Viola Jones face detection paper?

I am reading paper by Viola and Jones. There they have used ROC curve to measure the accuracy of their classifier. https://www.cs.cmu.edu/~efros/courses/LBMV07/Papers/viola-cvpr-01.pdf Could someone please explain how the ROC curve is plotted in…
Nemi Bhattarai
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What is the most suitable descriptor to use for object detection?

I want to build an object detector for several objects (cat, flower and car) based on viola jones algorithm. We can use HOG, LBP and HAAR-like descriptors. How we can know what is the most suitable descriptor according to each object?
ha_ell
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