Images in the frequency domain..

Started by ndes...@gmail.com in Image Signal Processing10 years ago 1 reply

Hi, I've been trying to understand more on frequency plots of images. 1. Assuming a 1d example of just a strip of an image; in the frequency...

Hi, I've been trying to understand more on frequency plots of images. 1. Assuming a 1d example of just a strip of an image; in the frequency map there are 'same' no. of frequencies as there are pixels. What is the reason for this? Does this have something to do with the Nyquist theorom. 2. What you see in the frequency domain is just a plot of all the spatial frequencies and thier amplitu...


image compression

Started by "amelie.quinet" in Image Signal Processing10 years ago 2 replies

Hi, I m working on image compression for my final training course. I am asked to compress the images 1600*1200 the most I can with the less...

Hi, I m working on image compression for my final training course. I am asked to compress the images 1600*1200 the most I can with the less loss I can... I am working with matlab, and trying to understand jpeg and jpeg2000. In fact my boss wants me to use jpeg2000 but EBCOT is very difficult. So i wanted to know, what makes jpeg2000 so different from jepg except DWT ? And what ca...


pixel values

Started by heidar mhr in Image Signal Processing10 years ago 1 reply

Hello guys, I have a question. I have an image and I am wondering how to use MATLAB to generate a text file that contains the pixel values of...

Hello guys, I have a question. I have an image and I am wondering how to use MATLAB to generate a text file that contains the pixel values of the image? Thanks Haidar


Non Local Mean Algorithm

Started by Benzun in Image Signal Processing10 years ago 1 reply

hello, I am working on a denoising of images by Non Local Mean Algorithim by Antoni Buades. Can anyone please explain me the...

hello, I am working on a denoising of images by Non Local Mean Algorithim by Antoni Buades. Can anyone please explain me the implementation. I am having difficulty understanding it. I would like to write a simple C program implementing it. I am currently Doing B.Tech 2nd year in NIT Trichy, India. -Benzun


How to compute the HSV histograms of a color image?

Started by vash...@yahoo.com in Image Signal Processing10 years ago

Hi all, Can anybody tell me how to generate a HSV histogram for an image. The HUE should use 16 Levels, SATURATION and VALUE should use 4...

Hi all, Can anybody tell me how to generate a HSV histogram for an image. The HUE should use 16 Levels, SATURATION and VALUE should use 4 levels each. Therefore the number of histogram bins to be used should be 16x4x4 = 256 bins. I know how to get the HSV histograms for the H,S and V channels separately(ie, 16+4+4 bins) though using the following code : RGB = imread(imagename); HSV ...


Entropy related criteria used in ICA

Started by zhou...@gmail.com in Image Signal Processing10 years ago

Hi everyone, I just started doing a project based on ICA. After reading the book "Independent component analysis" by Hyvarinen A ect., I have...

Hi everyone, I just started doing a project based on ICA. After reading the book "Independent component analysis" by Hyvarinen A ect., I have some questions which confused me a lot. 1. negentroy is defined as J(X)=H(Xgauss)-H(X). It has the advantage that it is scale invariant. J(X) is used as a criterion of find the mimimum of H(X) so that the signal is as non-gaussian as possible. 2. whi...


Vanishing point detection

Started by swet...@gmail.com in Image Signal Processing10 years ago 2 replies

Hello, Does anyone have information about vanishing point detection? regards swetha

Hello, Does anyone have information about vanishing point detection? regards swetha


Why Gaussian Models ?

Started by fido...@gmail.com in Image Signal Processing11 years ago 5 replies

Hi All, I might be asking trivial question,but i am forced to ask. I need to know why is it most of the application in signals processing and...

Hi All, I might be asking trivial question,but i am forced to ask. I need to know why is it most of the application in signals processing and image processing use Gaussian models . For example in image pattern recoginzation and in Background subtraction which uses Gaussian Mixture model. Please can someone help me out with this. Thanks in advance Fido


Open Source tools for machine vision

Started by vlya...@gmail.com in Image Signal Processing11 years ago 2 replies

Hello, I have to evaluate video enhancement algoritms ( such as image stabilization, contrast enhancement, pattern recognition ) with some pre-...

Hello, I have to evaluate video enhancement algoritms ( such as image stabilization, contrast enhancement, pattern recognition ) with some pre- recorded video sequences ( mpeg2/ts ). Can someone recommend me "easy-to-use" open source framework I can use to stream, filter and display results real time? I am looking to run it on generic PC hardware, OS can be Linux, any 32-bit version of Windows, ...


How does one "determine" the point spread function?

Started by Jeffrey Thalhammer in Image Signal Processing11 years ago 1 reply

Hello- Disclaimer: I have no background in optics or image processing, so I apologize in advance for abusing any terminology. I just...

Hello- Disclaimer: I have no background in optics or image processing, so I apologize in advance for abusing any terminology. I just discovered this mailing list via Google, and I hope that some of you might be able to help point me in the right direction. Here goes... I'm working on a software project that involves recognizing a certain pattern in extremely blurry images. I ...


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