Computer vision includes methods of processing, analyzing, images and high-dimensional data to form high level understanding and recognition of the scene or images.

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What are the works done till now in Video Event Detection?

I am doing a final year project on Video Event Detection. I know that there is a lot of work already done in Human Action Recognition. But instead of only human action, I want to work on event,scene ...
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21 views

Classification from a feature vector

I'm quite new to this; I'm try to classify textures as defective or non-defective. I've used a Gabor filter bank with Matlab which outputs a column vector of the Gabor features of an image. I have a ...
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24 views

Is there a way to perform 2-D image rotation by matrix multiplication?

In my understanding, unlike shifting and scaling, image rotation actually rotates the coordinates whereby interpolating the pixels at discrete positions. It is like a projection that discrete values ...
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How to choose scales(or deviations) for sampling in SIFT detection?

In SIFT's key points detection stage I have to make Gaussian filtered images at discrete scales(deviations). Is there any suggestive choice for these scales? Does it depend on specific inputs?
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17 views

extracting audio and video from video file

I tried the following code in MATLAB R2013b ...
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79 views

Object Detection Algorithms

I'm a complete beginner to object recognition. I need to identify and count how many of a certain type of Lego, in a picture full of different pieces of Lego, using MATLAB. The pieces of Lego I need ...
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3answers
57 views

Generate projection image by OpenGL or Matlab

I want to generate the "projection" image described as bellow. The left picture is the original picture and the right image is what I want. But, I have no idea about how to generate the right image. I ...
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106 views

Is it possible to hack camera calibration without having access to the camera?

Many times we have a stream of video to process without access to camera. Having access to camera matrix would be beneficial for various processing techniques. Is it possible to hack camera ...
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7 views

Public dataset for monocular visual odometry

I am planning to develop a monocular visual odometry system. Is there any indoor dataset available to the public, along with the ground truth, on which I can test my approach? Note: I am already ...
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1answer
51 views

OpenCV Motion Analysis: Optical Flow vs Motion History

OpenCV Motion Analysis Documentation lists multiple techniques for motion tracking: Sparse Optical Flow | calcOpticalFlowPyrLK, Dense Optical Flow | calcOpticalFlowFarneback, and Motion History ...
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38 views

I'm confuse how to use pdf to predict next state in particle filter

How can I make predict state/equation for next state if I have state space $[C_x,C_y,H,W]$ where $C_x,C_y$ is position of centroid object and $H,W$ is height and width of object contour?
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15 views

SURF SIFT detection

Do you have any idea if the surf extracted or detected interest points belongs to the same objects? I explain: SURF descriptor account the orientation of ip based on edges intensities around it. In ...
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22 views

Does accurate translation estimation using a camera matrix mean the orientation estimation will also be accurate?

Pose Estimation of single camera and planar pattern: If I have an appropriate camera matrix with intrinsic parameters that allows me to calculate translation of the camera relative to a chessboard, ...
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Can you average out focal length from different camera calibration sessions?

If I perform a number of camera calibration routines at a fixed resolution, with various sizes of calibration patterns (like checkerboards), at various distances and get various values for focal ...
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57 views

Why do eigenvectors specify the direction of fastest and slowest changes in the image

I'm reading Szeliski's Computer Vision:Algorithms and Applications. On page 212-213, corner detector is discussed. I can understand upto equation 4.8. From then on, I don't understand how come ...
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14 views

What is the difference between Harris Corner Detection and SUSAN Corner Detection?

What is the difference between Harris Corner Detection and SUSAN Corner Detection
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31 views

How does chessboard configuration effect camera calibration?

When calibrating a camera with a chessboard, are more squares better or worse? When would you use more or less? And how does the size of the blocks effect the calibration results?
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How to get extrinsic parameter in android?

Ultimately, I want to implement the following. http://www.cv-foundation.org/openaccess/content_cvpr_workshops_2013/W03/papers/Saponaro_Towards_Auto-calibration_of_2013_CVPR_paper.pdf I get rotation ...
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56 views

Sobel Vs Gaussian Derivative

What would be the most significant difference when using either a sobel filter or a gaussian-derivative filter, apart from the obvious difference of the size of the 2 filters?
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18 views

Need good resources to study 'Speeded up Robust features'

My current project is about Speeded up Robust features(SURF). I am a beginner in Image processing and new to this concept. Even though i found a lot of information on Internet, i am not able to find ...
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1answer
25 views

Pyramid Match Kernel: How to fit grid around data points?

I am planning to use Pyramid Match Kernel method for object recognition from depth images: I am going to extract a set of feature vectors $x \in \mathbb{R}^d$ for each object instance and then I want ...
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32 views

Motion Blur Filter

I want to implement Motion Blur Filter in C# using Emgu CV, what is the correct way to do this in fourier domain. I am currently stuck at how to perform multiply of Motion Blur filter and my Complex ...
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15 views

Could the X-Y resolution for a stereo camera setup be better than that of either of the cameras alone?

My understanding is that it shouldn't be different than the resolution of a single camera, since the actual X and Y coordinates of a point in space are defined from the point's image up to a scalar ...
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35 views

Bundle Min Hashing for Logo Recognition

In reference to the paper Bundle Min Hashing for Logo Recognition: Suppose we have bundles {2,5,18,444,678} and {2,5,79,368,841} and the vocabulary size is 1M. If we have just 1 sketch per bundle ...
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Normalized cut segmentation output correct or not?

I have implemented "normalized cut" segmentation. The change here is that, instead of giving an image as input, I have given an matrix of image. As my output looks odd to me. I need to know whether my ...
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2answers
30 views

LoG filter creating additional maxima in scale space

To create a scale space, I applied a Laplacian of Gaussian filter on the following image: After the scale space was created, I plotted circles around local maxima in scale space. However, instead ...
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1answer
83 views

AGAST vs FAST evaluation

In ~2006 the FAST corner detector was introduced. One of it characteristics is that you have to train a decision tree from some test image in order to learn the types of corners present and relevant ...
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71 views

Skeleton from distance map

Can anyone give some tips how to obtain Skeleton from distance map? I already managed to obtain skeleton using erased method (e.g. zhang suen) but it's time consuming because it's an iterative method ...
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53 views

Classifying animated GIFs as animation or film

Is there any known way of differentiating between frames of real footage and animated content? It seems like there's probably range of colors more likely to appear in a histogram for real footage, or ...
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21 views

Useful features for classifying color images

I have two sets of images. In one set, the background and foreground differs significantly in color (either background is dark and foreground is light or vice versa). What would be some useful ...
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17 views

Switching gradient computation in Lucas-Kanade pyramidal feature tracking

The following refers to pyramidal Lucas-Kanade. Given two images $I$ and $J$, we wish to find point $v$ in $J$ which corresponds to point $u$ in $I$. The initial step of the algorithm requires ...
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17 views

Equal contribution criteria during image pyramid construction

In their paper on Image Pyramids, Burt and Adelson state the following about pyramid generation. An additional constraint is called equal contribution. This stipulates that all nodes at a ...
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18 views

Sliding Windows, Global Image, Clustering and …?

Imagine that you have an algorithm that must detect some feature in an image. Right now, I know three "families" of search algorithms. Sliding Windows: You take a patch of some size (e.g. 15x15 ...
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100 views

Rectangle detection in “real life” images

I have seen a lot of posts here and on SO and on various websites, using Matlab, OpenCV, name it, on how to detect rectangles in an image. I have done it myself too, using Matlab. My usual steps were: ...
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2answers
51 views

Would the locations of SIFT features generally agree with features detected by Shi-Tomasi method?

I am having a comparison of different feature detection methods. So if we compare the SIFT (Scale-invariant feature transform) and Shi-Tomasi method, will their feature locations agree and why? Are ...
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38 views

.ptw Video conversion

On Video recording with IR camera, a file in .ptw is obtained. I want to analyze the file using standard software, like MATLAB. However, video processing in MATLAB requires the file to be converted to ...
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1answer
54 views

How to constrain the object detection problem?

How to constrain the object detection problem? It would be tempting to ask for precision such as: "It depends, does it have to be viewpoint invariant, is there going to be viewpoint changes, etc.?" ...
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84 views

Academic problem solving in Computer Vision

I am currently pursuing a Master degree of Engineering and I will have to write a thesis about solving a specific Machine Vision application. I have done some CV projects in the past but now I am ...
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41 views

Why does an ideal high pass filter on this image generate gray values

As seen from the image below, an ideal high pass filter was applied. Hence, stark changes in pixels from lighter to darker or vice versa show up on the filtered image. However, slower changes such ...
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40 views

Bhattacharyya distance for image segmentation explanation

I have a question need some your suggestion. I spent 2 months to resolve that problem but the result is not so good. Hence, I would like ask you some thing about my implementation. My goal is that I ...
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1answer
122 views

Histogram Intersection with two different bin sizes?

I have two images: A and B. Image A is a screenshot of image B, the original image. While there is noise in image A, the original features are still distinguishable. Histogram intersection tells us ...
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1answer
77 views

Separate sub-figures!

Any idea on separating multi-panel figures? There are 2 different sub-figures connected each other. Thanks!
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1answer
159 views

How to detect whether the object has triangular shape?

The task is to detect arrow from medical images. After segmenting, arrow-like objects can be connected with other connected components (noise). In this context, detecting a part of the object that ...
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91 views

The small red peak in the CIE standard observer

The human eye has 3 types of color cones: red, green and blue. Their spectral sensitivity peaks in short (S, 420–440 nm), middle (M, 530–540 nm), and long (L, 560–580 nm) wavelengths. See diagram ...
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44 views

Problem in openCV casade classifier

I am trying to train cascade classifier using "opencv_traincascade" utility. I'm having 100 positive images and 500 negative images. I have created .vec file using following command: ...
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27 views

Best method for texture classfication

I am working in medical and nature images processing . I want to find a popular method to segment texture image. Could you suggest a popular method to do it? For example: Gabor filter, tensor...
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73 views

Low pass filter to maintain edge information

I am looking for a kernel acting as a low pass filter that satisfies these conditions: $$K(-\mathbf{u})=K(\mathbf{u}) \tag{1}$$ $$K(\mathbf{u}) \ge K(\mathbf{v}), \;\; \text{if} \;\; ...
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1answer
89 views

Comparison between average kernel and gaussian kernel?

In image processing, we have two kinds of major kernels that are average kernel and gaussian kernel. For image segmentation, which is difference between average kernel and gaussian kernel? I found ...
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55 views

Real Time Object Tracking using image processing [closed]

How we can track a single selected object from multiple detected moving objects using single fixed camara?
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52 views

Floating point Descriptor evaluation

I have come up with a new descriptor(floating point). I want to evaluate this descriptor against SIFT, GLOH, etc etc. I am using the K. Mikolajczyk, C. Schmid, approach. The method is described in ...