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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Head pose estimation

I am looking for an efficient head pose estimation algorithm from facial features. What I already have: I already have implemented the code for stable facial landmarks(68 landmarks on the face). I ...
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224 views

Image processing: High pass filter to remove lowest 16 frequencies

How can I remove the lowest n frequencies of an image? Are the lower frequencies around the centre of the FFT result?
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475 views

how to compute horizontal angle of a pixel from a computer vision camera

My program needs to compute the angle of a pixel from a computer vision camera that has 120 degrees field of view, and resolution of 640 pixels wide and 480 pixels high. Program receives an X,Y array ...
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320 views

ImageJ Object Detection within AVI Stack

I am working on a project in which I am attempting to analyze a fish within a petri dish using ImageJ and an AVI clip of the fish under a microscope. My first hurdle is to locate the fish within the ...
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To estimate the uncertainty of Slicing holes from an image?

I am thinking to estimate the uncertainty of holes photographed from the bottom and top side. The difference of the same hole photographed from two sides is distributed as Gaussian. The length of ...
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82 views

Object detection algorithm

I need detect object in series of pictures. This object has something like nonsymetric relief structure with some irregularities. In this conditions. Light conditions can change from almost dark to ...
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How to use wavelet decomposition for feature extraction (of fMRI images)?

I have a dataset consisting of fMRI images (from mice) which are divided into 4 groups (different drug dose levels applied). Each fMRI image is 4D, that means each voxel is a time series. For each ...
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73 views

Can Log Gabor Filters be used on an edge detected image

i'm doing a project on log gabor filters, can i use log gabor filter on an edge detected image for feature extraction,and use these features for classification by ANN
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45 views

Isolating overlapping image

Using a diffraction grating in front of my smartphone's camera, I can decompose light sources into their spectral components. The problem is that the background is not always dark and there might be ...
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100 views

Fill incomplete holes in 3d image

I'm trying to analyse a series of CT scans of coral samples, but am fairly new to this sort of image processing. The problem I've hit is that a lot of the coral is hollow (in the images), and even ...
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181 views

Optical Flow Problems

I was wondering if any of you guys could help me with the next 3 problems. They're about estimating the lamda on the Optical Flow equation $E = E_s + λE_c$, for different situations that try to ...
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296 views

Image processing for eye movements

I have series of images extracted from a eye tracker video for both eyes. is there any image processing algorithm/method/technique available to find the following from those images: Horizontal eye ...
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96 views

Filtering an image with a helmholtz-type equation

I'm attempting to apply the following PDE as an image filter to smooth a discrete heightmap with a helmholtz-type equation as described in this paper. It seemed like an interesting alternative to a ...
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466 views

Initialization of population for genetic algorithm in matlab

I randomly generated initial 10 population(let each of size n) of genetic algorithm as follows ...
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1answer
550 views

3D point cloud to 2.5D graycale image (metric) [Halcon?]

I have a problem ragarding transferring a point cloud to a 2.5D metric grayscale image (gray value gives depth information). I start with a three channel image of 32bit floats with each pixel ...
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161 views

what kind of information we can get if the auto-correlation for an image is a ring or two rings?

I did the auto-correlation for an image by Mathematica. The auto-correlation function shows rings as follow..I am sorry that I can not attach the original image here. From the following auto-...
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40 views

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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134 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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671 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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199 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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183 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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505 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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98 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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58 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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301 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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83 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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51 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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1answer
1k views

Generate the Matrix Form of 2D Convolution Kernel

We know that a convolution can be replaced by a multiplication with a toeplitz circulant matrix. Meaning, assume I have convolution kernel $h$ and matrix $I$ (of size $m \times m$ for example), then ...
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145 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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128 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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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
903 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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171 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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129 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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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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148 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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716 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
695 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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991 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: ...