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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19 views

How to compare the qualities of two interpolation (image resizing) algorithms?

I am implementing image resizing algorithms (Bilinear, Bicubic, Lanczos and a few others). How do I quantitatively compare them? I am thinking of considering a large sample of images and running ...
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13 views

Difference Between Least Square Error Recognition, Logistic Regression, and a Certain Nearest Neighbor Neural Network

Least Square Error Recognition from JavaOCR finds the least mean square error from a training image pixel by pixel. Logistic regression from this site, on the other hand, seeks to minimize the error ...
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0answers
28 views

What is the advantage of weighted median filter over median filter?

I could not find any proof or comparison of weighted median and median filters.Yes the more occuring pixel contributes much but what should be the criteria of choosing weight function.And any ...
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1answer
37 views

Sharpen defocused image

Using OCR, I want to extract text from product packages using Google Glass. However, because of the fixed focus of the camera the package pictures are blurred. Is there a way to sharpen the image? ...
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1answer
39 views

Isolate the non blurred part of foucsed image

I have an image taken by a mobile phone camera with focus on a part of it let say a face or whatever. I want to know -approximately- where is the focused area. For example, a bounding box around the ...
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2answers
81 views

What's the best technique to determine if the contents of two images are the same?

I need to run comparisons on the output of hundreds of frames of simple 3D-rendered characters. Perceptually, many of the frames are exact duplicates. Based on this, I assumed something like a ...
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19 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 ...
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1answer
18 views

Difference between ycbcr and ycbycr

I see in a paper mentioning ycbcr as well as ycbycr. I am wondering what is the difference between the two? In the figure, the first two lines show ycbycr but the two bottom lines show ycbycr?
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16 views

What exactly affine covariant features are?

I was reading about different blob detection algorithms. And I found an statement that determinant of Hessian is a affine covariant. What does it mean?
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13 views

Hue out of range

I don't why.. but for some reason is my histogram showing that the max hue value of my image is around 339498 which doesn't make sense for me.. I am trying to create a mask, that recognizes the ...
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1answer
38 views

How to calculate the luminance of an image?

Is there any method for calculating luminance of an image? As from wiki got to know Luminance is an amount of energy perceived by the observer and LUX is different from brightness. But still is ...
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11 views

I am trying to model the mechanse respone behaviour of a model to predict joints in matlab [closed]

How to do calculus in matlab and how to I get the equation of the curve in matlab give us an example please? ...
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0answers
15 views

Coherence of specific area of an image

I have to detect an object in an image. The manner that I am using gives me a number of possible areas of the image that may contain the object. I want to check which is the most coherence area of ...
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1answer
26 views

3D intensity map for grayscale image

I've got images of blood drops in grayscale and I want to generate 3D data where the first two dimensions represent the area of interest and the 3rd dimension represents the pixel intensity of that ...
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1answer
23 views
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1answer
18 views

Locally Adaptive Thresholding - How to Detect if Image Block is Uniform

I need to implement a locally adaptive threshold algorithm on a grayscale image in matlab. I use a sliding window over the image and calculate the threshold for the block using Otsu's method, which ...
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0answers
14 views

Corner detection of image in Matlab

I'm trying to detect the corner of a binary image(boundary image)Function using Freeman Chain Code algorithm.Code for corner detection is taken from Matlab Central(function name is "chaincode") I ...
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1answer
39 views

How to find out whether guassian or salt& pepper noise present in an image, Is there any algorithm

Is there any algorithm for identifying the noise in an image I have to identify whether the noise present in a mammogram image is guassian or salt& pepper.
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33 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 ...
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1answer
18 views

Dark image separation

So I have an image. I take it into HSV format and v has its intensity values. now the intensity values of v vary from ...
6
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1answer
77 views

What is the type of noise in this image?

what reason could make the noise/effect in this image? Below is the original Thanks!
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1answer
26 views

Fragmented recovered image using a Phase Retrieval Algorithm named Error-Reduction

After reading the paper Phase retrieval algorithms: a comparison by J.R.Fienup. I implemented the Error-Reduction Algorithm in MATLAB. The initial phase input was randomly generated, so the final ...
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1answer
33 views

Remove checkered noise from an image

I'm trying to remove what looks like a checkered noise pattern that has been added to an image. Comparing the 2D FFTs The one on the left is the original, while the middle one is the corrupted ...
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0answers
19 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 ...
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1answer
40 views

Skew detection and correction using Fourier transform

I was trying to implement skew correction method for scanned documents using the method described in this paper. The algorithm steps: 1- Threshold the image . 2- Find the fourier transform. 3- ...
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1answer
42 views

Can a digital image be considered as a tensor ? or have a tensor like structure?

I am wondering if one can assume that a digital image has a tensor structure. I mean for example when we talk about isotropy in image processing, we are talking about the intensity arranged in a ...
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8 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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1answer
22 views

How do I implement LIBSVM for multiclass classification using java?

I am currently working on an image classification project ,where i need to use bag of features model with libsvm(HIK kernel) for classification.I have extracted sift feature and created a visual ...
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1answer
36 views

Recursive Implementation of the Gaussian Filter

I'm trying to implement an IIR form to approximate the Gaussian Blur Filter. I'm working with the article "Recursive Implementation of the Gaussian Filter" by Ian T. Young and Lucas J. van Vliet. ...
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10 views

Image denoising algorithm in matlab

I'm trying to denoise a grayscale image using the two level denoising algorithm as shown in the following block diagram. I used wiener filtering for denoising.Code is given below. ...
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16 views

Edge detection of image in matlab

I'm trying to extract edge from an image. I used the following algorithm.Input image(e11) which is a 512 * 512 grayscale image is also given. Find the morphological gradient of input ...
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0answers
13 views

Plotting Basis of 3D Steerable Filter

I am plotting isosurface plots of Basis of 3D Steerable filters which should look like Spherical Harmonics of first Zero, first and second order plots. Correct me ...
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0answers
14 views

Generate human skin pattern with Reaction-Diffusion equaton or other model

I have been looking for a Reaction-Diffusion equation (or whatever model) which accurately generates this kind of pattern on human skin. I have tried multiple models, inventing own equations, ...
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1answer
35 views

What kind of information can we obtain from curvature for exemplar-based inpainting?

I just want to know what kind of information does Curvature suggest to us? I've seen an article that used from the curvature of an Image. I can't understand what's the purpose of the author or it's ...
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0answers
89 views

Detect text regions within scanned documents

I'm working on text detection task from scanned documents to detect text regions only and separate them from images, graph, etc. Here is my idea : First i'm using OpenCV wrapper for C# (Emgu) on ...
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23 views

How to detect a hologram in image?

I've been searching the net and wasn't able to properly formulate the query to find some clues in the subject above. Having an image like this: How do you go about detecting/separating/removing ...
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24 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 ...
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0answers
21 views

Characterized image dataset for detection and segmentation

I'm looking for an image dataset for image segmentation and recognition. Additionally, I would like it to be categorized according to several image parameters, such as: object size in image, rotation, ...
0
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1answer
44 views

Calculating Affine Transformation matrix from 4 corner points

I'm trying to develop a sudoku solver, using image processing, ocr with neural networks and such. I've got the bare solver working, I can successfully interpret numbers and letters from a picture. All ...
1
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1answer
43 views

I have some questions about background subtraction with Gaussian Mixture Model (GMM)

I'm learning about Gaussian Mixture Model (GMM) for background subtraction.. And have some questions about it.. In Chris Stauffer paper "Adaptive background mixture models for real-time tracking" ...
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2answers
76 views

Transformation of coordinate set

I have a problem in which i have a video that was taken from the side of the subject, something like this and i need to transform the coordinates of the subject to be as if the photo was taken from ...
0
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1answer
32 views

Fast Fourier Transformation using parallel processing coding for image processing [closed]

I'm now working in parallel precessing -and i want a full code for fast Fourier transform(FFT) written parallel processing Code for any image processing application
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34 views

How to straighten the edges?

Are there standard efficient ways/algorithms to make edges in an image more straight or axis-parallel (horizontal or vertical) ? I have images that look like this: This is part of a segmentation ...
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1answer
29 views

Medical Image quality assessment

How to objectively assess the quality of a medical image(CT,PET,MRI)? What factors should be considered?
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1answer
29 views

Difference between subsampling and downscaling (image)?

I know that there are many ways to upscale (interpolate) an image using bilinear, bicubic, sinc... Somehow, these same algorithms can also be used to downscale an image. But when it comes to ...
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0answers
12 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 ...
2
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0answers
59 views

Weighted Nuclear Norm Minimization for Image Denoising

Recently, I saw new published papers like this paper about denoising images using Weighted Nuclear Norm Minimization (WNNM) approach and I am wondering what is the physical intuition behind it. The ...
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2answers
52 views

Vehicle detection in matlab [closed]

I am new to matlab and computer vision. I used the code given in the link to detect cars. But the problem is the shadow is also being detected and tracked. Can anyone tell me how to modify the code so ...
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2answers
50 views

Removing the 'red' artifact from my JPEG

I have a JPEG that originally came from a IP Camera. I have converted the JPEG to a bytes and have uploaded it to my server. Upon receiving it on my server I save it to disk. When I view the image it ...
2
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0answers
61 views

Efficient Hessian-Laplace blob detector implementation

As it is mentioned in a paper for SURF, it is possible to approximate hessian determinant using integral images. If I want to implement Hessian-Laplace detector, is it feasible to also approximate ...