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

learn more… | top users | synonyms

0
votes
0answers
11 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 ...
1
vote
1answer
19 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, ...
-1
votes
0answers
32 views

How to find the corner of a whale fin?

I have got the images of whales and I extract the fin from the whale and then apply an edge detection algorithm which gives me a 2 dimensional vector with the edge values. I can plot this vector to ...
1
vote
3answers
27 views

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 ...
0
votes
1answer
49 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 ...
0
votes
0answers
8 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
1
vote
1answer
27 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?
0
votes
0answers
8 views

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 ...
2
votes
0answers
48 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?
0
votes
0answers
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 ...
2
votes
1answer
23 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 ...
0
votes
0answers
22 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 ...
0
votes
0answers
14 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 ...
0
votes
0answers
27 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 ...
2
votes
0answers
30 views

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 ...
1
vote
2answers
29 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 ...
0
votes
1answer
67 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 ...
0
votes
1answer
44 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 ...
0
votes
1answer
52 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 ...
0
votes
0answers
19 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 ...
0
votes
0answers
16 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 ...
0
votes
1answer
16 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 ...
0
votes
0answers
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 ...
1
vote
1answer
69 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: ...
2
votes
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 ...
0
votes
0answers
26 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 ...
1
vote
1answer
53 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.?" ...
3
votes
1answer
82 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 ...
1
vote
1answer
39 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 ...
0
votes
0answers
29 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 ...
1
vote
1answer
111 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 ...
0
votes
1answer
76 views

Separate sub-figures!

Any idea on separating multi-panel figures? There are 2 different sub-figures connected each other. Thanks!
1
vote
1answer
149 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 ...
4
votes
1answer
86 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 ...
0
votes
0answers
39 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: ...
0
votes
0answers
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...
-1
votes
1answer
69 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} \;\; ...
-1
votes
1answer
86 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 ...
1
vote
1answer
53 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?
0
votes
1answer
43 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 ...
0
votes
1answer
51 views

How to detect a inhomogeneity region in image

I have an image that includes object and background. However, the object appears some inhomogeneity region due to illumination. My work is that how to detect inhomogeneity region. Which is feature can ...
0
votes
1answer
34 views

How to choose the number of codewords in bag of words model

In the bag of words model, generally is it better to have more codewords or less? For example, if I have 1000 x 20 raw features, then what would be good value for codebooks? I am thinking of smaller ...
1
vote
0answers
23 views

High triangulation error

I have implemented a 2D->3D point triangulation method, which uses 2 poses P1 and P2 and 2 points back-projected to z=1 point1 and point2 to recover depth: ...
1
vote
3answers
64 views

Camera Calibration using Single Input Image

Given a camera, permanently located at the same position, angle and distance from what is being captured, and a single calibration image ( a row of vertical lines [ | | | | ] ), how would one go about ...
0
votes
0answers
50 views

Find and track deformable curve in noisy images

I need to find and track the location of the bottom of multiple deformable curves within a sequence of images. The images are taken roughly 5 seconds apart and there can be considerable deformation in ...
0
votes
0answers
28 views

Affine Parameter Optimization using simulated annealing

I am working on a project to compare images in the database. I use color and gradient orientation as features of the image and these features are not rotation invariance, therefore to compare well I ...
1
vote
0answers
315 views

Train a Cascade Object Detector in MATLAB

I am trying to train a cascade object detector in MATLAB using the built in functionality from the Computer Vision Toolbox. I’ve taken 500 photo’s of the sole of my shoe. Every photo is taken from ...
0
votes
0answers
27 views

Fastest implementation of Features from Accelerated Segment Test (FAST) algorithm

I understand that there are different implementations (both in software and hardware) of the FAST algorithm. What is the fastest implementation of Features from Accelerated Segment test (FAST) ...
1
vote
1answer
335 views

Zernike Moments' implementation in OpenCV

The reason why Hu moments were implemented in OpenCV and why Zernike moments were not implemented is looking like their performance similar as stated in this paper. As stated in the paper Zernike ...
1
vote
0answers
225 views

MPEG-7 descriptors' implementation in OpenCV

I'm looking for implementation of MPEG-7 descriptors which are compatible with OpenCV's recent versions and containing "region-based shape descriptor ART(Angular Radial Transformation)". I ...