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Questions tagged [computer-vision]

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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11
votes
1answer
313 views

Recover curves from noisy collection of points

Background: I'm trying to make a system that tracks a number of bubbles in a video I'm implementing the bubble detection in the single image case using the Circular Hough Transform. Due to occlusion, ...
9
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2answers
2k views

Are there any computer vision algorithms specifically targeting depth images?

I've been looking into marker detection algorithms to use with a kinect based application, and the majority of the work I've been able to find is obviously focused on feature detection in 'normal' ...
12
votes
1answer
909 views

Image Denoising with Better Edge Preservation

I have the input image : and the output of vein detection for the leaf using a Gabor filter, but the output is really noisy: I tried using Total variation denoising however the results are not good: ...
17
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4answers
8k views

Intuitive explanation of tracking with Kalman filters

I would much appreciate an intuitive explanation for (visual) tracking with Kalman filters. what I know: Prediction step: Dynamic system state $\mathbf x_t$: target location at time $t$ Measurement $...
5
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2answers
93 views

Viewpoint dependant deformation of objects in photos

I have a question concerning the deformation of objects in photos. Which deformations can an object depicted on a photo undergo through viewpoint and condition changes? Some deformations I have in ...
16
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2answers
594 views

3D reconstruction of an image based on depth of intensity levels?

Is there anyway of segmenting objects based on how far they are from the viewer? Can color values assess this sort of a thing for us? How will intensity levels help in determining how far the object ...
4
votes
1answer
131 views

How to get to shoulders localization on image photo? [closed]

I have a project on my university. I have to localize from video where are shoulders of person in movie. Do have any advise how to get to this? I thought about corner detection or some kind of ...
8
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1answer
2k views

How to remove reflections from images?

I've been playing around with making images better and removing all the unwanted disturbances from it. I found out a major concern would be removing the unwanted reflections that might come. I've ...
0
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1answer
5k views

calculating similarity scores between similar and different classes?

I have images for 99 person for each person i have 5 images . i have this function [similarity] = ssim(img1, img2, K, window, L);where K,window ,L are previously determined with their values. now , ...
2
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2answers
4k views

Object Recognition using bag of features using matlab [closed]

I want to write a MATLAB program for simple object recognition using bag of features. In short, I want to first extract the features from an image, create a visual library using those features, then ...
10
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3answers
3k views

Camera calibration/pin hole camera model and working out 3d position

I have a calibrated camera and have the intrinsic parameters. I also have the extrinsic parameters relative to a point (the world origin) on a planar surface in the real world. This point I have set ...
3
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1answer
2k views

Wavelength filter with OpenCV

I am new to OpenCV and DSP. I want to code a filter which act like a real optical filter. When you filter the image, the output looks like shotted with a $550nm$ optical filter lens. Like a Bandpass ...
0
votes
1answer
1k views

what is the possible solution for the Intra-class variations poblems?

my poblem is that i have a database for human dorsal hand veins ,but with intra-class variations , so this problem have a large effect on my results when i need to do matching between my samples for ...
9
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1answer
6k views

What is the link between the homography computed over 2 images and the homography computed over the same images upside down?

With OpenCV, I compute the homography between, say, these two images: and Don't worry about the strange white form on the right side, it is due to the smartphone holder I use. The homography, given ...
12
votes
2answers
15k views

How do I retrieve texture using GLCM and classify using SVM Classifier?

I'm on a project of liver tumor segmentation and classification. I used Region Growing and FCM for liver and tumor segmentation respectively. Then, I used Gray Level Co-occurence matrix for texture ...
9
votes
1answer
2k views

Good features / algorithms for recognizing car-models in images

I have a question concerning object recognition, especially recognizing car-models! I am at the beginning of a work about identifying the same car-model in different images. At the moment I think one ...
8
votes
2answers
3k views

Generate the Convolution Matrix of 2D Kernel for Convolution Shape of `same`

I want to find a convolution matrix for a certain 2D kernel $ H $. For example, for image Img of size $ m \times n $ , I want (in MATALB): ...
47
votes
6answers
19k views

Best way of segmenting veins in leaves?

I have done a lot of research and found out methods like adaptive thresholding , watershed etc that can be used of detecting veins in leaves . However thresholding isn't good as it introduces a lot of ...
16
votes
2answers
572 views

What image-processing techniques are ideal for this particular shift/scale invariant template matching?

A problem I had originally discussed here has evolved, and might have gotten a little simpler as I studied it in some more and attained new information. Bottom line, I would like to be able to detect ...
16
votes
2answers
33k views

Are there any good open-source (well, free) handwriting OCR programs?

The title asks it all. I have before me a data entry task that I'm not too enthusiastic about: 50-100 pages of handwritten sign out/sign in logs. The format of the logs may help. Pages are ...
10
votes
1answer
24k views

Adaptive Thresholding for liver segmentation using Matlab

I need to segment liver from an abdominal CT image using Adaptive Thresholding. But I get the entire foreground separated from the background alone. I need only the liver part of the foreground ...
14
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4answers
2k views

basic hsb skin detection, neon illumination

i hope this is the right place to ask. otherways sorry for my mistake and pleace advice me a better site. i'm trying to implement a super simple skin detector using some range of hsb image. i'm using ...
11
votes
1answer
280 views

Image Processing method for spiky selection

I have an input as a 3D binary image and the preferred output below: Input: Preferred Output: What image processing methods should I look for if I am to have only the spiky object(s) remain, just ...
4
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1answer
932 views

Topological skeleton matching techniques

What are the most common and best topological skeleton matching techniques? Suppose I have skeletonized object and corresponding 2D model of this object. What are the next steps to match pattern? ...
5
votes
1answer
398 views

image feature extraction

We are given a set of grayscale image patches obtained from images after edge detection. Each patch is 10x10 pixels with intensity varying between 0 and 255 for each pixel. This set may contain a very ...
4
votes
2answers
157 views

Struggling to find a good definiton for Gabor-Descriptor

I am attempting to implement the Gabor Descriptor based on the following paper Image Copy Detection Using a Robust Gabor Texture Descriptor. It is the best paper that I have found on the subject. It ...
13
votes
3answers
18k views

How to compute camera pose from Homography matrix?

Say I use only one calibrated camera. From this camera, I get images A and B. I know the homography between A and B, computed through OpenCV's findHomography(). I know the pose (rotation matrix R and ...
12
votes
2answers
521 views

What methodology to use for discrimination of different (musical?) tones

I am trying to research and figure out how best to attack this problem. It straddles music processing, image processing, and signal processing, and so there are a myriad number of ways to look at it. ...
28
votes
5answers
16k views

Good language for computer vision?

I am trying to implement a content based image retrieval system but before I do so I would like to get an overview of some programming languages suitable for this task (having good libs and such). ...
1
vote
1answer
911 views

one to many images matching in matlab?

i have database for 50 person ,it is 250 images (5 images/person) , i need to perform one to many matching between images for recognition persons. so , i divided the image as 2 parts (one for ...
7
votes
1answer
3k views

Get histogram of edge lengths/orientations in an image using OpenCV

In the process of trying to estimate whether a ROI contains [Japanese] text, I need to get a rough count of edges, hopefully binned by length and/or orientation... I think this would give me strong-...
11
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4answers
2k views

Image Recognition

Looking for an open-source system that allows commercial use to do image recognition on a massive and organically growing collection of 2-D images where the only known variations will be: Scaling ...
2
votes
1answer
2k views

List of all available ARM+DSP processors for surveillance

I have come across TI's C6000/Integra. I want to know is there any other similar or better ARM+DSPs available. Specially for surveillance/vehicle number plate recognition etc. Having camera input at ...
4
votes
2answers
3k views

how can i perform a registration to 2D images using ''rigid " transformation in matlab?

i need to perform registration to 2D image using"rigid transformation" in matlab .i need this for measuring the similarity between my images .any one know how this can be done using matlab? an ...
1
vote
1answer
1k views

is it possible to matching b / w images without feature extraction steps? if possible which algorithm may be more suitable?

these are example of my image i have a 245 images similar to it ,i obtained these b/w images after preprocessing stage , i want to use them for recognition persons(not verification) in matlab. can i ...
2
votes
2answers
860 views

Triangulation from set of points from left camera

in my program there are stereo cameras. The cameras were stereo calibrated. I have a set of 2D-Points from left image (for example, it could be some Harris Corners from left images). And the task is ...
2
votes
1answer
927 views

Vector Quantization in Hidden Markov Models

In the field of Gesture Recognition and Speech Recognition (using HMM classifiers), do multiple HMM classifiers (one for each class) share common Codebook (i.e common set of symbols) in Vector ...
14
votes
1answer
5k views

Binary robust independent elementary features (“BRIEF”) understanding

How are the descriptors in the BRIEF algorithm matched to each other? How is the template image found in the another image? How do we compare the descriptors? I have read that article but didn't ...
5
votes
2answers
341 views

Function for response over image scales

I want to write code in matlab to find a characteristic scale of an image patch. I have an image patch X, I need to maximize function F(X,sigma) so that sigma is ...
65
votes
4answers
48k views

What are some free alternatives to SIFT/ SURF that can be used in commercial applications?

As far as I understand, both SURF and SIFT are patent protected. Are there any alternative methods that can be used in a commercial application freely? For more info on the patent check out: http://...
14
votes
2answers
899 views

How can I change the formula to detect the barcode in every angle? - MATLAB

How can I change the formula to detect the barcode in every angle? ...
5
votes
2answers
458 views

How do you measure the accuracy of a stereo system?

I have a philosophical question of sorts for users familiar with a multi-view stereo setup. Imagine that I need to measure the dimensions of a large building and I take several photos of the building ...
5
votes
1answer
218 views

How to amplify regions with specific color in an image?

I want to amplify regions with a specified color in an image. For this purpose I have defined a simple function $B(x,y)=s_r(x,y) \cdot w_r + s_g(x,y) \cdot w_g + s_b(x,y) \cdot w_b$ which produces a ...
26
votes
3answers
1k views

How to find tennis courts in aerial imagery

I'm interested in finding all tennis courts (and other similar well defined features like basketball courts) in my county, and I have aerial imagery of good (but varying) resolution, but I'm not sure ...
-1
votes
1answer
428 views

Which are the steps to extract contours/shapes from depth videos?

I am trying to create a histogram of the depth videos (converted to grayscale first) in order to apply a threshold to keep only highest values, and then do some dilation in order to extract contours. ...
9
votes
2answers
2k views

Surface detection

How would one segment large area's of gray (ranging from white to black) from an image ? (If you know this in opencv, you may answer by saying what you would do in opencv). For example given this ...
9
votes
1answer
607 views

Accurately measuring relative distance between a set of fiducials (Augmented reality application)

Let's say I have a set of 5 markers. I am trying to find the relative distances between each marker using an augmented reality framework such as ARToolkit. In my camera feed thee first 20 frames show ...
7
votes
1answer
191 views

Minimization of Essential matrix

A problem in computer vision and 3d reconstruction is getting the camera's intrinsics parameters. A common solution is to use an object in which one knows the measurements of the shape before hand, ...
16
votes
3answers
6k views

Contours matching - finding contours displacement

I found contours on two images with same object and I want to find displacement and rotation of this object. I've tried with rotated bounding boxes of this contours and then its angles and center ...
14
votes
2answers
2k views

Profile Matching in a Point Cloud

A point cloud is generated using uniform random function for (x,y,z). As shown on the following figure, a flat intersecting plane (profile) is being investigated ...