Circular convolution to Linear convolution.

Started by shashanktotre in comp.dsp11 years ago 1 reply

Hi, I am new to this programming world, and i really need some serious help. I have done a program in which i design a filter in frequency...

Hi, I am new to this programming world, and i really need some serious help. I have done a program in which i design a filter in frequency domain, then i take a CT image, which is a 3d image, read each voxel and make a 1d array. then i equal the number of samples for both the data set. so i have equal samples. then i do convolution using fftw3 library. but what happens is that i am doing circula...


optimal linear prediction in image processing?

Started by MBALOVER in comp.dsp9 years ago 7 replies

Hi all, I am wondering if you guys know any paper or book chapter discussing optimal linear prediction for 2D or more specifically for...

Hi all, I am wondering if you guys know any paper or book chapter discussing optimal linear prediction for 2D or more specifically for image processing? I tried to look for it in the library in my university but could not find it. Thank you.


Convolution-based image interpolation

Started by Michel Rouzic in comp.dsp13 years ago 33 replies

I'm looking forward implementing image interpolation in one dimension at once, however I don't really know how to do it. Linear interpolation...

I'm looking forward implementing image interpolation in one dimension at once, however I don't really know how to do it. Linear interpolation doesn't fit me good, I need something better, more like cubic spline interpolation, but the only problem that well implementing it doesn't sound like such an easy thing (I will if I have to, but it definitely won't be my first choice for that precise ...


Re: ANNOUNCEMENT: New image format

Started by Miles Bader in comp.dsp12 years ago

Industrial One writes: > On Nov 22, 10:18 pm, He's Late wrote: > > Doesn't matter, he's way too late. The new HD Photo 16-bit-support >...

Industrial One writes: > On Nov 22, 10:18 pm, He's Late wrote: > > Doesn't matter, he's way too late. The new HD Photo 16-bit-support > > image format is already being supported in programs like PhotoLine > > 32. It's already doing all that stuff. Microsoft has a verrrry bad record of foisting really crappy data formats on the world. Prev


(image process) are there any guidelines on how to design good filters to enhance an image?

Started by walala in comp.dsp16 years ago 16 replies

dear all, I am facing the following problem that I need your help: We have in our experiments some special images need to be processed. My...

dear all, I am facing the following problem that I need your help: We have in our experiments some special images need to be processed. My task is to look at these images and see how to improve/enhance them. In fact we/I have no idea on how much enhancement we can get. So what I've done in the past month is to play with different kind of filters to try on the images. We use PSNR as jud...


Image processing with DSP's

Started by Martin Euredjian in comp.dsp16 years ago 2 replies

Interested in opinions and thoughts as to which DSP's might be good/best for real-time image processing. We currently use FPGA's. It would...

Interested in opinions and thoughts as to which DSP's might be good/best for real-time image processing. We currently use FPGA's. It would be interesting to learn what can be done with DSP's. Are there any that have efficient ways to implement such things as FIR filters, for example, or matrix transforms, etc.? How about dealing with SDRAM/DDR SDRAM frame stores? Are there any that can ...


what are the appearance of aliasing in image and audio processing?

Started by kiki in comp.dsp15 years ago 4 replies

Hi all, I've heard a lot of aliasing. What do they look like in image and audio/speech/music with aliasing? I did not see/hear any real...

Hi all, I've heard a lot of aliasing. What do they look like in image and audio/speech/music with aliasing? I did not see/hear any real aliasing stuff, so the concept of aliasing looks abstract to me, although I know how it occurs in terms of mathematics... I am also wondering about the anti-aliasing filter before downsampling... By filtering, you lose information, right? It is har...


Speed up of 2D Lorentzian filter?

Started by Christian Gollwitzer in comp.dsp3 years ago 14 replies

Hi all, I'm looking for a way to speed up a special image reconstruction algorithm. [*] Actually, the filter is very simple linear filter....

Hi all, I'm looking for a way to speed up a special image reconstruction algorithm. [*] Actually, the filter is very simple linear filter. In essence, the image is Fourier transformed, multiplied by 1/(1+A*(u^2+v^2)) (u, v are the conjugate coordinates of x,y) and transformed back. Realistic images can be as large as 4096x4096, so with padding an 8kx8k FFT is performed on seve...


FFTW image processing frequency value question...(ad nauseum)

Started by dpjones0 in comp.dsp11 years ago 3 replies

Hi, I have been using FFTW to do some image processing, including cross correlations, etc. I have found it to be very useful. I've used the...

Hi, I have been using FFTW to do some image processing, including cross correlations, etc. I have found it to be very useful. I've used the r2c/ c2r combination as well as forward and reverse fftw_plan_dft_1d, based on examples I have found online. I have been reading this discussion group that has helped me figure a lot of things out. However, in my latest application, I still seem to be s...


column problem in image processing

Started by alb in comp.dsp7 years ago 19 replies

Dear all, I am trying to process images which are coming from a frame transfer CCD with electron multiplication which is shooting pictures at...

Dear all, I am trying to process images which are coming from a frame transfer CCD with electron multiplication which is shooting pictures at the sky during the night. My task is to find the stars within the picture and calculate their position - relative to the CCD coordinates - and magnitude. From time to time the raw image looks like showing a big difference of illumination between c...


Phase scrambled FFT - Question from beginner

Started by sam in comp.dsp13 years ago

Hello, I am new to using FFT and I was wondering if anybody could point me in the direction of any scripts (C++ or Matlab) or any algorithm...

Hello, I am new to using FFT and I was wondering if anybody could point me in the direction of any scripts (C++ or Matlab) or any algorithm overviews to perform the following.... Computing the FFT of an image, setting the phase values to random values in the interval 0 - 2pie, while maintaining Hermitian symmetry, then backtransforming to produce a real image. Any help would be much ...


which one is the most successful scheme to reduce blocky artifacts in low bit rate JPEG image?

Started by walala in comp.dsp16 years ago 12 replies

Dear all, After reading more and more and got answers from here, I now am more clear about the interesting problem: Give an image...

Dear all, After reading more and more and got answers from here, I now am more clear about the interesting problem: Give an image encoding/decoding system, in hardware implementation, it will have round-off or finite word-length error; and even with perfect floating-point arithematic, there is still block artifacts. I don't know if they can be treated unitedly or not... I want to ask w...


digital watermarking and cryptography

Started by محمد احمد in comp.dsp7 years ago

i'm working on digital watermarking and cryptography , i'm trying to insert a set of data, containing the signature of the original image, the...

i'm working on digital watermarking and cryptography , i'm trying to insert a set of data, containing the signature of the original image, the data specific to the patient and his diagnostic and then it will be shared in a network. which technique or algorithm to embed that information without affecting the image quality as this may cause misdiagnosis. any help or advice will be appreciated


digital watermarking and cryptography

Started by محمد احمد in comp.dsp7 years ago 1 reply

i'm working on digital watermarking and cryptography , i'm trying to insert a set of data, containing the signature of the original image, the...

i'm working on digital watermarking and cryptography , i'm trying to insert a set of data, containing the signature of the original image, the data specific to the patient and his diagnostic and then it will be shared in a network. which technique or algorithm to embed that information without affecting the image quality as this may cause misdiagnosis. any help or advice will be appreciated


Generating SSB by a DAC with Hilbert image rejection (AD9786)?

Started by MM in comp.dsp16 years ago 2 replies

Hi all, I am again looking at the AD9786 datasheet: (http://www.analog.com/UploadedFiles/Data_Sheets/34595181746736AD9786_prc.pd f) and in...

Hi all, I am again looking at the AD9786 datasheet: (http://www.analog.com/UploadedFiles/Data_Sheets/34595181746736AD9786_prc.pd f) and in particular on Fig.13, trying to understand how the chip works and whether I can generate a SSB signal with it (supposedly I should be able to). I wrote a simple MATLAB script (see below) to simulate the image rejection algorithm implemented in the AD97...


Confusion about 2D DFTs

Started by Michel Rouzic in comp.dsp11 years ago 12 replies

Here's my problem. I have an image to be processed (well, deconvolved pretty much), and a star-shaped impulse response I want to deconvolve it...

Here's my problem. I have an image to be processed (well, deconvolved pretty much), and a star-shaped impulse response I want to deconvolve it with. The impulse response is symmetric in both the vertical and horizontal axis and pretty much centred, but not very precisely. Of course both the image and the impulse response are appropriately zero- padded as to avoid any circular convolution. ...


magical Black Hole image

Started by Steve Pope in comp.dsp4 months ago 5 replies

The Event Horizon Telescope team of course deserves a huge amount of credit for their results. But it's interesting how they got there. ...

The Event Horizon Telescope team of course deserves a huge amount of credit for their results. But it's interesting how they got there. Here's an article with some non-technical discussion: https://fivethirtyeight.com/features/forget-the-black-hole-picture-check-out-the-sweet-technolog y-that-made-it-possible/ Their data is too noisy to actually create a black hole image. So they a


Advice needed for PhD research: MCMC for image analysis

Started by Beihai in comp.dsp16 years ago 2 replies

Hi, I will be embarking on a PhD program. Some supervisors suggested Markov Chain Monte Carlo on medical image analysis. I just know that it...

Hi, I will be embarking on a PhD program. Some supervisors suggested Markov Chain Monte Carlo on medical image analysis. I just know that it can be used to detect cancer cells/blood capillaries et al. Think it branches off from stochastic geometry. Can someone offer some advice? 1. What textbook can I look up? 2. Generally how is this field? Is it at its infancy, with substant...


references for image compression with neural networks

Started by cyril prasanna raj.p in comp.dsp15 years ago 1 reply

Where can i find the recent literature on image compression with neural networks?

Where can i find the recent literature on image compression with neural networks?


TI DSP uP vs FPGA

Started by geoffrey wall in comp.dsp15 years ago 7 replies

I am trying to determine the best solution for real time image/video processing in hardware... Does anyone have any thoughts as to which...

I am trying to determine the best solution for real time image/video processing in hardware... Does anyone have any thoughts as to which solution (FPGA or DSP uP) is better. I would like to run several (roughly 10) convolution filters as well as perform image histogram equalization operations on each frame of a gray 640x480 frame at a rate of about 15 fps. Any comments would be most appr...