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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140 views

What does 'correlation' and 'de-correlation' mean in image-processing?

Here are some problems: Does it mean these is some relationship among neighboring pixels? And I've read about DCT has a property of de-correlation,I have a doubt whether it means DCT neighbor ...
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15 views

Acoustic characteristics of thoracic diaphragm

I am looking for any kind of information about the acoustic characteristics of the thoracic diaphragm. In particular, I'm looking for characteristics which will allow to differentiate it from other ...
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944 views

Why correlation coefficient template matching perfoms better than cross-correlation and square-differences method

I am using this template in OpenCv's match template function by converting all images to grayscale. Here are my result using sum of square differences,cross correlation and correlation coefficient....
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88 views

Application of BIC, MDL, AIC

I understand that mathematical motivation behind Bayesian Information Criterion (BIC), Minimum description length (MDL), Akaike information criterion (AIC) are different but I am assuming that there ...
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206 views

Where to get an image dataset for sports?

I am doing a project on classification of sports images,for which I have not found a proper dataset on the net. I am working on sports namely cricket, basketball, soccer, hockey, baseball and tennis. ...
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95 views

Segmenting simple objects without shadows

I am trying to segment very simple objects like boxes and bottles. I am using GrabCut and it works extremely well when there are no shadows or when the shadows are soft - but as soon as there is a ...
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31 views

How to get an objects dimensions from video

I want to be able to measure an object using the camera on my phone. How would I go about getting an objects width and height from a video? My first thought was some type of 3D tracking of the video. ...
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71 views

Comparing the spatial frequency between groups of images

I have 2 groups of images, and I want to compare these groups based on the spatial frequencies of the images. In the end, I'd like to be able to say "group A is/is not significantly different from ...
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128 views

Image Subtraction using Pre-bayer data (.pgm)

Not sure if this is the best stack exchange but I'll give it a shot. I am performing background subtraction to collect Electroluminescent emission (i.e image w/ emission - image w/o emission = ...
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310 views

phase shift between two images (matrices)

I'm trying to find the phase shift between two 100x100 matrices, s and p. To start with I'm using two sine waves (2D) slightly shifted. I manage to compute the correct amplitude spectrum (using the ...
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72 views

Understand about registration between spatial prior and original image

I am working in level set/active contour method using spatial prior information . The main papers that I am focusing:"Automatic segmentation of neonatal images using convex optimization and coupled ...
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77 views

Are there any other libraries for Image Processing using hadoop?

I have been looking for libraries for Image Processing using hadoop, but by now, only have been able to know about hipi, and to some extent hadoopy. Are there any other libraries for the same? Hipi ...
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171 views

pre-processing to improve feature detector before tracking

I am trying to make tracking for soccer player, I need to detect features from this player and then estimate the distance difference of these pixels over number of frames. first I have to detect the ...
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114 views

what is in intuitive explanation of local derivative pattern (LDP)?

Zhang et al. proposed the LDPs for face recognition . They considered the LBP as the nondirectional first-order local pattern operator and extended it to higher orders ( th-order) called the LDP. is ...
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203 views

Sobel Filter Operatios

I have an image which has a vertical line which is 2 pixels wide and 4 pixels long and the remaining image is black. Now I want to find the edges in the vertical direction and for that I use the ...
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251 views

Looking for a better way to posterize or normalize the colors of an image

I have very little experience with image processing or signal processing in general, but I'm willing to learn. I've been experimenting with a way to, uh... "flatten" the colors of certain kinds of ...
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1answer
267 views

Haralick features, am I approaching this correctly?

I'm trying to personalise a custom CBIR by adding more features not only based on colour, but based on textures' features. What I don't know is if I'm approaching this well with Haralick's features. ...
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68 views

Primitive Feature Detection

I am trying to check whether this black circle is exist or not on my images. My current approach is like that; Hough Circle detection Crop the outer roi Adaptive threshold count zero pixels if ...
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2answers
542 views

CLAHE - Redistributing excess pixels among histogram bins

In order to clip an image's histogram to a maximum value, according to the CLAHE algorithm, the excess pixels (above the clip limit) will be distributed equally among all the histogram bins (While ...
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182 views

Image warping with subpixel accuracy

I am trying to test the sub-pixel accuracy of an optical flow method and need to generate some synthetic data to do so. I start with an image $I_0$, which is a Perlin noise image and a set of sub-...
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27 views

Aligning frames with common elements

I am new to image processing and had the following question: I have take some 512-px grayscale images. The images were take in such a way that all images were of the same spot, but there was some ...
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151 views

Equivalent of the Shepp-Logan phantom for video denoising

The Shepp-Logan phantom is a standard test image used in reconstruction algorithms as well as image denoising. Does an equivalent image sequence exist for testing video denoising algorithms? I know ...
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415 views

How to implement HOG with trilinear interpolation by Matlab?

I am studying HOG. I have find the code code1 and code2 about HOG. However, both of them don't implement trilinear interpolation. I have also read some websites, including web1 and web2. I still don't ...
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510 views

Gap Filling Contours / Lines

I have the following image: and I would like to fill in its contours (i.e. I would like to gap fill the lines in this image). I have tried a morphological closing, but using a rectangular kernel of ...
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1answer
303 views

What are the keywords to find an algorithm that detects embossed text from a 3d model?

Currently I am doing an acadmic research about an idea which came into my mind lately. I have a 3d model and I want to extract embossed text .. anyone knows any papers? or if it is already proposed? ....
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55 views

Looking to understand line artifacts in “overscanned” image

Essentially I'm looking for an explanation how the second image results from a capture of the original. Possibly you've seen something like this before and you can tell just from looking at the result ...
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2k views

how to get segmented OPTIC DISC from retinal image?

i have been segmented some image of retina. but the result is not good as i hope. for one image i can get good segmentation, like this image my code is from some reference in internet, in below i ...
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3k views

Image super resolution algorithm in Matlab

I'm trying to implement a simple Image super resolution algorithm (DWT-Based Resolution Enhancement ) in the following paper http://www.ripublication.com/aeee/52_pp%20%20%20405-412.pdf I tried to ...
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793 views

Fingerprint minutiae matching

I am working in a fingerprint recognition project using C code running on embedded system. After processing the fingerprint image, I have the minutiae now. I tried to matching two sets of minutiae by ...
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469 views

Polygon Segmentation technique

I am working on Automated GUI components Segmentation problem. My Images are very simple as it has GUI components such as Buttons, text box and other polygons as you can see in the diagram (a). ...
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441 views

Are discrete wavelet transform based statistical features invariant to rotation/translation/scale?

I'm reading a paper where image classification is done. Their approach is to use the discrete wavelet transform with bi-orthogonal wavelets of degree 3.5 and decomposition of level 3 on images. Based ...
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1answer
225 views

Question About Linear and Circular Convolution - 1D and 2D

We know that applying a filter on an image is called correlation or convolution depending on the filter angle. In Gonzalez I have read that we can apply linear convolution on an image. Here I have a ...
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52 views

Detecting inset images/videos from a video

I want to detect multiple rectangles in a video, each of which features a different content, but running simultaneously. This is typically seen during debates on news channels. For example, in the ...
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116 views

Gonzalez question solution

If I have the histogram of an input image as Gaussian probability density function of the form: $$P_r(r)=\dfrac{1}{\sqrt{2\pi}\sigma}e^{-\dfrac{(r-\mu)^2}{2\sigma^2}} $$ where: $\mu$ and $\sigma$ ...
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72 views

Interpolation methods for radar and acoustic imaging and potential pitfalls

A) What are the most common methods used to remap data for current generation imaging radars and acoustic sensors? B) What are some of the pitfalls in these methods? For example, in the past, at ...
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756 views

Ways to find three curves from palm image

I am asked to extract three curves from palm images. original image expected result. The curves has lower intensity than ...
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110 views

Feature selection of Gabor filter

I am working with Gabor filter with level set method here. As you known, gabor filter gave many filter output. Some of them is not necessary. Could you suggest to me some method that can choose best ...
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758 views

Visual regression test - Extract elements of GUI-Screenshot - MSER OpenCV

For a visual regression test I need to compare screenshots of webpages (different release-versions). I started with pixel by pixel compare. Actually I split the screenshot in different parts (maybe ...
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5k 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 ...
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153 views

filtering out specific waves in scattering pattern

I have the following (experimental) image, with its correponding raw data in .csv format here. The pattern represents the scattering of a laser field off a point defect located in the center. One can ...
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177 views

How to get the quaternionic analytic signal of a image?

The 2D discrete image signal's quaternionic fourier transform can be described as F(u,v), and its 2D analytic signal often be described as: $$ F_q(u,v) = (1 + \mbox{sgn}(u))(1 + \mbox{sgn}(v)) F(u,v) ...
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630 views

No proper kmeans clustering of images in matlab

I am having 1200 face images in my training set.There are 2989 test face images. I am using eigen faces (PCA) for feature extraction. I am using kmeans clustering. I even tried all 2989 test face ...
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480 views

Impact of different padding schemes in Frequency domain image filtering

I understand, that image padding is necessary in order to prevent wrap-around effects due to circular convolution. My set of questions are related to different padding schemes. Zero Padding is easy ...
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930 views

Image Registration C#

I'm trying to fuse different images of the same scene which each image have a different focus. I've been told that first I have to perform an image registration to the images. Right now, the result ...
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78 views

Image Compression (JPEG) - Show the Effect of Number of Coefficients on Quality

write an m-file that will take the"cameraman" and produce a image quality or difference matrix for spectral selection method.The image properties are a sfollowings: For spectral selection: image1:DC ...
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97 views

Can the Fast Fourier transform be used to compute the magnitude of moiré

I am experimenting with image down-sampling and would like to calculate a numerical magnitude for alias-induced moiré patterns. Is it possible to do this by analyzing the frequency-domain (FFT) of ...
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57 views

The relationship between zero level set and thickness information

I have one problem that need you help. I am try to find the relationship between active contour and thickness information. For defination of thickness we can find at thickness measuring and active ...
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146 views

Image objects dispersion and diversity measures

I have images like below: I want to find some measures describing black spots dispersion and diversity. First measures I use are mass center off all black spots, mean area of spot, stdev of area ...
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375 views

How to understand energy function in thin plate splines?

guys! I have carried out some experiments using matlab warp tools from here. But the results are not good, so I decide to read its original paper Principal Warps: Thin-Plate Splines and the ...
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96 views

question about the frequency of Gabor filters

The Fourier transform of 2D Gabor filters is shown below: F is the radial frequency of the Gabor functions. Another parameter Fm is denoted as highest central frequency. Fr is the constant frequency ...