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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Amplitudes and phases of transform of an image

I have recorded an image of a large macromolecule and after several types of image analysis, have obtained a rotationally averaged image, that is not quite perfect, but appears to show 6-fold symmetry....
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102 views

How does Arbib's clustering method work?

Recently in Image Processing I've been studying image clustering (or segmentation) methods and one of them is Arbib's. I understand the main idea behind it from which you start with one cluster with ...
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141 views

Saddle points, Nodes and Edges definitions

I am working on some algorithm implementation, however being new to image processing, I have some questions about some of the definitions used. UPDATE: for those asking for more information, this is ...
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734 views

Distinguish between 2D and 3D objects according to depth

I'm trying to distinguish by code between a real 3D object and its picture - a 2D object, based on depth information. However the picture (= the 2D image) might be captured from noisy background, so I ...
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203 views

How do I deal with occlusion, warping, or perspective distortion for object detection

I am using SIFT features for detecting logos in clothes. SIFT is quite powerful, as it is scale invariant, but how do I deal with the problem of occlusion and warping? More specifically, the logos in ...
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187 views

Creating a texture image from existing image

I have some unusual question. I have searched online and couldn't find something similar to what I want to achieve. I have an image, and I want to create a new image from it (in the same size), so ...
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518 views

Estimate Image power spectrum of the noise

I want to implement Wiener filter. I have original image and image blured with linear motion. The one thing I am lack of(to implement it) is Noise power spectrum. I know that it is hard task. I've ...
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103 views

How do i detect if an image has a gradient or not?

I have coloured images, some may be just clipart, some may be artwork, both could be with or without gradients. Before i run a colour counting algorithm on them, i want to detect if the image has ...
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2k views

Why Normalized Cross Correlation Score of different templates is high?

I am using OpenCv's built in template matching function to search for an object in image. I am using Normalized Cross Correlation Method.The function is returning a value which I think indication of ...
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61 views

What equation describes black alpha on a white image?

What equation best describes the alpha content of a black colored pixel applied to a white pixel when measuring the resulting pixel intensity? For instance given a white pixel: argb : 255, 255, 255, ...
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1k views

Image enhancement algorithms for adjusting shadow, exposure, contrast etc

For those who have either used Picasa/Photoshop, they would see different image enhancement options such as: Change exposure Change shadow Change highlights Change vibrance I have searched online a ...
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319 views

High Pass Filter, effect of applying it on this image.

I am having question about the HPF. In particular, it is having a high pass guassian filter which is applied to the original image below. High pass filter should only detect edge (lots of change in ...
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84 views

Image Processing - Identifing/locating Random Solid Blocks of Colour

I am not overly familiar with image processing. I know a little about it from University, but I have not really done any for a while and I have found myself with a problem that requires it. What I ...
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52 views

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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52 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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151 views

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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132 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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1answer
1k views

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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1answer
945 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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175 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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132 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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49 views

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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154 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
729 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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117 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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449 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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191 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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732 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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1answer
223 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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1answer
143 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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1answer
167 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
33 views

How to identify text size using image processing?

For a side project at home, I have several pdf documents in "standard" form (White background, black font for text). For several pages, I have footnotes which are different in size from the main body. ...
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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
50 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
160 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
506 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. ...