This tag covers signal processing where input is an image, such as a photograph or video frame and the output could be an improved or altered image, parameters related to the image or information about features within the image.

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10 views

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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1answer
25 views

Estimating the variance of noise using median function (?)

By investigating the implemented code of an accepted paper, I encounter with following relation to estimate the variance of noise in an image: $$ \sigma = \frac{median ...
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0answers
9 views

Compute the Gibbs energy for second-order neighborhood

I have a question about Gibbs distribution in Stochastic theory. In which, it defined a clique as a a subset $C$ in the whole image $\Omega$ if two different element of $C$ are neighbors. Figure 2 ...
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1answer
21 views

How do I compute the gradient vector of pixels in an image?

I'm trying to find the curvature of the features in an image and I was advised to calculate the gradient vector of pixels. So if the matrix below are the values from a grayscale image, how would I go ...
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0answers
21 views

eliminating white areas without sharp boundaries

I have images of following type: and As one can see, in the corners of the images there are white areas which don't have sharp or well defined boundaries; the intensity gradually decreases. ...
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0answers
18 views

What's the optimal filter size for a 2D Gabor filter

I started to experiment with Gabor filters to extract various image features from usual camera snapshots (that's the image domain: everyday snapshots with a very diverse range of subjects). ...
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1answer
25 views

Which anatomical model to use as “ground truth” for validating an MRI segmentation method?

I am research in brain segmentation task that classify a brain in to 3 classes : White Matter, Gray Matter and CSF. To validate my method, I used Dice Coefficient that compare my result and ground ...
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1answer
15 views

Amplitude of an image

If I take a two dimensional image and conduct a fourier transform on it, I would get a two dimensional matrix of complex values. If I want to find the amplitude of each value, is that the same as ...
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0answers
46 views

How to detect those areas which are lightened up

I have two images of a scene, IA and IF (this is not no-flash and flash image case). They can be thought of as two binary masks. Image IA: Image IF: If you observe closely, there is a change ...
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1answer
39 views

why wavelet is more suitable for image compression compared to DCT?

Everyone knows that JPEG2000 can obtain much better compression result than JPEG. The fundamental transform behind JPEG2000 is wavelet while the basic transform in JPEG is DCT. So my question is why ...
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2answers
36 views

Selective image compression?

Forgive me if this is the wrong site for this question. Here's my problem: I am creating a game where players have to search for a hidden detail within the overall image. I downloaded an 11MB ...
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0answers
35 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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0answers
18 views

Find similarity rating in trajectories

I've got trajectories encoded in black and white. These are stored in a matrix with dimensions 150x150 (i.e. black = 1, white = 0). An example of two trajectories below (plotted): My objective is ...
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0answers
23 views

what is the difference among noise,blurring and contrast? [closed]

I want to know the following what is the difference among noise,blurring and contrast ?
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1answer
27 views

How to get the X and Y Coordinates of the circles from an image?

I am building an simple website to show the first train arrival and last train departure timing in Singapore. I already wrote a simple code which could be found here. I am placing an circle on top of ...
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0answers
20 views

Transformation validation

I am trying to see the validity of my geometric transformation, by imposing a point I got from a tracker in the original image and superimposing it on the image after the transformations. The point ...
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1answer
19 views

What's the best way to compare the same object from different “crops” or angles within multiple images?

I read a similar question, but I'm not sure the techniques discussed will help me. Take for example the two following images: I'm trying to determine if the above images are sourced from the ...
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2answers
161 views

relation between luminance and eigen values of an image

There are some research papers in the literature which apply Singular Value Decomposition (SVD) on an image to decompose the image matrix into U, ...
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0answers
25 views

What is difference noise reduction technic on additive gaussian noise and poisson noise?

As I know the camera noise are consisting like poisson noise and additive gausian noise. I want to know about What is difference noise reduction technic on additive gaussian noise and poisson noise? ...
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1answer
35 views

what is the difference between HSV and CIE-Lab color space? [closed]

when do we use HSV color space and when do we use CIE-Lab color space?
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0answers
49 views

Cannot see effect of modifying eigen values in Python (SciPy, NumPy)

I am doing some experiment for increasing the intensity of low exposure image by changing (increasing) the eigen values. In Matlab I apply Singular Value Decomposition on the image matrix to get ...
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1answer
96 views

What does zero-mean noise mean?

I don't know where to start from. and this question might be very silly, I have found such as comment from someone at here, "I think if you noise is zero-mean it doesn't matter, if not it does (you ...
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2answers
66 views

Identification of a given barcode as either 1 D or 2 D

I am working on an algorithm (in MATLAB) to identify/classify a given bar code (image) as 1 D or 2 D. I have considered using the contrast of THE IMAGE matrix as a parameter or using the FFT of the ...
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0answers
8 views

significance of real valued coefficient and complex valued coefficient

What is the significanceof real valued coefficient and complex valued coefficient with respect to DCT and DFT.And how does it effect signal processing?
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1answer
149 views

How to learn image processing / computer vision in a practical way?

I am new to the field of image processing / computer vision and I find it very hard to get my hands on the subject. I read a lot about the basics/theory but I feel in no way able to use this knowledge ...
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0answers
22 views

Is affine the right transformation for coordinate change?

I have a video which was used in a tracking program. In that program the object being tracked receives per frame X,Y coordinates which are not the same as in the my video. I have a few coordinates ...
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0answers
15 views

How to combine SURF and Harris points

As we know at Matlab, there is function to detect Harris or SURF feature individually. Then I need to combine these two list of features from both the Harris and SURF to make the matching more ...
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0answers
18 views

How to calculate Coherent Change Detection?

I have two images which I wish to compare the difference between using coherent change detection and I'm having some trouble figuring out how to apply these signal processing equations to my data in a ...
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0answers
64 views

Get problem to understand “Topological Structural Analysis of Digitized Binary Images by Border Following” Suzuki Abe

I'm confuse with their explanation about definition 1 notation of 4- (8-) and 8- (4-) in Suzuki Abe paper "Topological Structural Analysis of Digitized Binary Images by Border Following" pg 34, and ...
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0answers
28 views

How to understand the mathematical notion of a image?

An analog image is a 2D function $$ f \in L^2 ([0, 1]^2 )$$ where the unit square $[0, 1]^2$ is the image domain. (Gabriel Peyré Advanced Signal, Image and Surface Processing, chapter 1) How to ...
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0answers
29 views

Satellite image quality assessment

I have satellite image and after I processed it, it became better than the original, how can I prove that it is better such that the psnr and mse give me low quality as it is different than the ...
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2answers
45 views

how to add two images in one, next to each other

I have two splited images from diference matlab files. Now i need to merge them, near to each other. I tried supblot, imadd,cat methods, but nothing works. Please help me. rezult after sublot ...
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0answers
31 views

Need Help how to remove unwanted edge detection

Hye everyone. Really need help. How to remove the branch that i circle in the image. What parameters i should use. Really appreciate your help.
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0answers
23 views

How to preprocess fmri image with FSL?

I need to preprocess fMRI images with FSL (motion correction etc.). I never used FSL before and never done preprocessing. Is there a good tutorial which describes step by step how I can do the ...
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0answers
22 views

How to implement extended structure tensor

I am implementing an extended structure tensor that defined as where (*) is convolution operator; K_sigma is a Gaussian kernel with standard deviation sigma. The subscripts x and y denote the ...
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1answer
36 views

Image region-based representation

I have a homogeneity image that includes two regions $\Omega_1$ and $\Omega_2$. How to represent the image by decomposition of two regions? For example, the famous way is representing by the mean ...
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0answers
25 views

What does visual clue means ?

Given a keypoint p detected in an image I . What does visual clueof the keypoint p mean ? ...
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1answer
71 views

How to estimate the noise of an image?

I want to know how to estimate the noise of an image? Also is this represent the camera's noise? Does anyone know how to estimate the noise of an image or camera? Update: Especially, I want to ...
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0answers
19 views

How to represent the relationship of pixels within a cluster

I have a question about image processing that need your help. I have an image I that includes foreground (FG) and background (BG) regions. I want to represent the relationship of pixels within these ...
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0answers
29 views

Finger Detection on various backgrounds

I tried tracking down the finger placed in the frame. Constraints: Algorithm works in live streaming of USB Camera, so there will be a lot of background changes. Algorithms tried: Tried ...
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5answers
477 views

Noise Removal from an image using Opencv

I tried removing noise from the image shown below using Median Blur in OpenCV. But i'm not able to remove the colour noise completely as it is done in Neat Image. Any suggestions.? 1. Original Input ...
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2answers
34 views

What is meant by isotropic diffusion? [closed]

I am working on diffusion of medical images, and I have come across the term isotropic diffusion. Can anyone explain it for me?
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1answer
59 views

How to Linearise an Input Image before applying Color Correction?

I'm doing color correction on Raw images taken from Camera directly. I want to make my Camera reproduce same colors as my Target camera. Here are the steps I'm following: Take Target Color values ...
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0answers
18 views

How to compute Homography between two images whose Camera Pose is known?

I want to compute Homography Matrix between two images whose Camera Pose is known, because it is not very stable to compute Homography Matrix from 2D correspondence. I only found camera Pose from ...
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0answers
69 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
27 views

Comparing Images by Defining a Reference Model

I have a microscopy system which periodically captures an image to be used for shading correction. Because these images are captured on tissue slides containing, well, tissue, as well as possibly ...
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3answers
53 views

what are frequencies in a digital image? [duplicate]

I don't completely understand the term " frequency" with respect to digital image processing. for 1D electrical signals , its pretty easy to understand , visually too. higher the frequency - more ...
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0answers
23 views

strange occasional periodic pattern in phase correlation output

I am working on a pattern recognition algorithm where a template is to be searched in a query image (Standard phase correlation stuff). However, in my correlation output I get some strange periodic ...
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2answers
42 views

Good inhomogenity measures in images?

Can you advise me on good inhomogenity measurements in an image? I am trying to find the borders where homogenous zones touch inhomogenous ones in a image. I am going to work with sick lung ct ...
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0answers
27 views

Fit a plane on a 2d picture

My supervisor gave me the hint, to fit a plane on a 2 dimensional image and substract it from it before doing the fast fourier transformation to reduce low frequencies. I get the low frequencies ...