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Questions tagged [image-processing]

In general, image processing is any form of signal processing for which the input is an image, such as a photograph or video frame.

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Understanding a mathematical statement in image processing

I am reading a document on Image processing and couldn't analyze a statement in it. For any $k \in \Psi_s$, the family of values $\{u[\varphi(p+l)+k-l]:l \in \Psi_s \}$ is representative of the ...
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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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What is purpose of correlation kernel? IIs it high pass filter or low pass filter?

I am research about correlation kernel and I have some questions that need your help. Let see the pp. 3302-3303 in the paper: Changyang Li, et al., Robust Model for Segmenting Images With/Without ...
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130 views

How to store generated eigen faces for future face recognition?

My code works in the following manner: 1.First, it obtains several images from the training set 2.After loading these images, we find the normalized faces,mean face and perform several calculation. ...
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How to perform a Stockwell Transform on a 2D matrix

I was looking at performing a Stockwell transform on a matrix (or an image as it has two directions - the matrix I am interested in has a spatial dimension and a time dimension, but this should make ...
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926 views

What are the various techniques for detecting Walls in the Building(Architectural) floor plan Images?

I have to process building floor plan images to extract Walls from the structure. It is trivial in case of binary images; but the images in our case are colored, and each have different color of walls....
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173 views

How many way to reduce overfitting problem of Linear classificationH

I am working in linear classification such as y=ax+b. where x={x1...xn}. But the method has weakness that is overfitting problem. Could you suggest to me one method or one way to reduce overfitting ...
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38 views

How many features of given image

assume that I have a set of image and segmented image of a object in image (training set). Now, I want to measure features of object in image based on the training data. But I don't know how many ...
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131 views

Matching 2 undirected weighted graph in matlab

Consider 2 undirected weighted graph as shown in figure.Consider first graph as G1 and second graph as G2.Graph G1 consist of vertices V={F1,F2,F3,F4,F5} and Graph G2 consist of vertices V={N1,N2,N3,...
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37 views

Please suggest me good algorithm for video segmentation based on changing background?

Iam having 1 min video.I need to cut the video into 5 segments depending on changing background.Please suggest me good algorithm which can be easily implemented in matlab.Please provide me helpful ...
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Pedestrian Re-identification during tracking

During the multi-camera tracking, there is a situation where one person moves from one camera's coverage area to another. In that case that person has to be re-identified(as the one from previous ...
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187 views

Optimal way for curve detection

I am totally new to image recognition and image analysis and have a project concerning detecting a smooth curve on a uniform background (white/black/any color) and then be able to follow this curve ...
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1k views

Why does the inverse fourier transform of a lowpass filter have complex components in matlab?

I am quite confused whether the following numerical differences i find are just severe round off errors made by matlab, or something i am doing wrong. The following happened when trying to see what a ...
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3k views

Image Processing/Analysis for Eye blink detection

I am working on a eye blink detection project in Matlab. By this moment I have been successfully extracted the images of pupil of eye from the real time video captured via a web cam. But I am stuck ...
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62 views

Slicing of images

I have used the following command to slice a large image into blocks of 2x2 pixels: convert -crop 2x2 +repage Logo.jpg sl%d.jpg When I attempt to put the blocks ...
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151 views

Encoding the HOG features

I have got a video containing 200 frames and i am extracting low level features at pixel level. Then i am dividing the entire frame in to small spatial patches (say of size 7x7) and creating a feature ...
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718 views

Digital Image Processing - Contemporary Research Topics

I need to propose a masters degree topic, and I'd like it to be in digital image processing. What are currently relevant topics in this area? I suppose that I'm looking for some kind of optimization,...
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59 views

Most likely transformation of an image

A graylevel reference image is transformed displacing each pixel. The magnitude of the displacement follows a bidimensional gaussian distribution. When two pixels in the reference image fall in the ...
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3answers
722 views

How to select the specific frame with object

I am detecting the object from the live camera through feature detection with svm , and it read every frame from camera while predicting which affect its speed , i just want that it should select the ...
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1k views

HOG descriptor algorithm

I would like to implement a HOG descriptor in C++. I found an implementation of this code here. An extract of the code follows: ...
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115 views

Transfering the concept of time delay to image processing

I've just come across a paper that interrelates the covariance matrix of time discrete signals to their autocorrelation function (or a time-delay, respectively), i.e. $$\mathbf{C} = E\{\mathbf{x}\left(...
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85 views

How can I create polygon estimates of each body part/limb that is present in an image which always contains one person?

Background I am working to identify and isolate each human limb of a known person, in pose, in an image which is relatively noisy. It should also be noted that the image is a snapshot extracted from ...
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276 views

State of the art in Cancer tumour detection using Digital image processing algorithms

I am trying to understand how image processing is applied for detection of cancer tumor using image processing. Towards this direction I am trying to get latest information i.e state of the art in ...
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446 views

Finger print skeletonization without using matlab functions

I am trying to thin foreground pixels of a finger print until they are one pixel wide without using the built in bwmorph and thin operations. Can anyone explain to me how to write them in matlab ...
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190 views

Calculating the SNR of a video

I have a video and I want to calculate the SNR for it. I know how to do it with an audio signal, but with a video I don't have a clue. I'm using SCILAB for the analysis.
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729 views

Using GavabDB for 3D face reconstruction from frontal image

Project: 3D face reconstruction Input: 2D frontal face Image Output: 3D face Reconstruction and expression simulation Platform: Matlab or Opencv cpp. I found out after study that 3D Morphable Models ...
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210 views

Is there a difference in bicubic interpolation of images vs patches?

I need to extract low resolution patches from an image. For example, 32x32 patches from a 500x500 image. Method One Down res 500x500 image (by bicubic interpolation, both down res and up res). ...
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142 views

Hand Jitter Problem

I am currently developing algorithm using openCV C++ for implementing laser as a mouse.Currently am having an issue of hand jitters.(ie. The presenter's hand may shake unnecessarily which may cause ...
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1answer
1k views

How do I plot color distribution of HSV image in matlab

I have a dataset of images representing human skin. How do I plot the skin color distribution in HSV color space and YCBCR color space. However, I'd like ignore the "value" or "brightness" in both ...
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1answer
96 views

Detecting blobs that connects to any other blob, maybe with OpenCV

In the image, I connects to universe, but II and III not. I need to detect both II and III, also I if possible. Is it possible with current computer vision libraries?
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166 views

Digital Image Processing

I am trying to extract only urban aeas from satellite imagery Using Matlab. I have applied some edge detectors like canny and also used morphological functions and I am able to extract all the ...
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1answer
47 views

Best way to fill an image placed into a larger box without creating artificial edges?

If you are training a neural net for a bunch of images of different size, and you have to put them all in a same-size enclosing box for input to the neural net, what's the best way to fill the ...
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2answers
2k views

Matlab Laplacian filter implementation

I implemented a Laplacian filter for the Lena image, but I get an unexpected output. For input: I get output: I used the mask M = ...
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1answer
49 views

How to improve the linear grey level transformation?

I am testing the linear grey level method stated in enter link description here.Now it is clear that this method have a major problem: If there are already pixels of values 0 or 1, there won't be any ...
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1answer
144 views

Quadtree decomposition of Discrete Wavelet Transform using bio4.4/CDF wavelet

My problem is pretty basic but fundamental. It relates to the way discrete wavelet transform behaves for biorothognal 4.4 or CDF wavelets. When using most wavelets (e.g., CDF 9/7 or bio4.4 or ...
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1answer
501 views

Differences between 2D and 3D medical Images

I have two questions: What is the difference between 2D and 3D medical images? Assume I have a 2D image and for example it contains 1000 ROIs. Each ROI is a matrix and we can convert it to a vector. ...
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1answer
370 views

fft2 of interferometric image - how to interpret the result in term of dominant frequency

I have an interferometric image which shows fringes at a certain frequency, basically a dominantly periodic signal overlaying the information that I want to extracthere are the fringes that I want to ...
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2answers
123 views

How to get started in image processing

I want to start studying image processing and need some tutorials for beginners. I am not bad at Mathematics and good when it comes to programming. I want to use the ...
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2answers
816 views

Comparison Between Average Kernel (Box 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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2answers
214 views

Is there any difference between the 2D continuous and discrete Gabor filter when it comes to MATLAB implementation

I want to know the difference between the 2D continuous and discrete Gabor filter when it comes to Matlab implementation. I found many files related to 2D Gabor filter on Mathworks File Exchange but I ...
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103 views

Image processing - Why is sum of values of a blurring filter = 1?

Usually, blurring filters have the sum of all the values in the filter matrix equal to $1$. Why is it so?