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Questions tagged [noise-reduction]

Anything related to noise reduction techniques and tools. This tag may be employed for questions on algorithms (and corresponding implementations) used to reduce noise in digital data and signals.

Anything related to noise reduction techniques and tools. This tag may be employed for questions on algorithms (and corresponding implementations) used to reduce noise in digital data and signals.

298 questions
24
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9 answers

OpenCV - Removal of noise in image

I have an image here with a table.. In the column on the right the background is filled with noise How to detect the areas with noise? I only want to apply some kind of filter on the parts with noise because I need to do OCR on it and any kind of…
clarkk
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20
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1 answer

Which algorithm is used for noise canceling in earphones?

I want to program software for noise canceling in real time, the same way it happens in earphones with active noise canceling. Are there any open algorithms or, at least, science papers about it? A Google search found info about non-realtime noise…
samlowry
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18
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3 answers

OpenCV using k-means to posterize an image

I want to posterize an image with k-means and OpenCV in C++ interface (cv namespace) and I get weird results. I need it for reduce some noise. This is my code: #include "cv.h" #include "highgui.h" using namespace cv; int main() { Mat imageBGR,…
nkint
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15
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2 answers

Remove noisy lines from an image

I have images that are noised with some random lines like the following one: I want to apply on them some preprocessing in order to remove the unwanted noise ( the lines that distort the writing) so that I can use them with OCR (Tesseract). The…
test
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14
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1 answer

Remove noise from wav file, MATLAB

I've only used MATLAB as a calculator, so I'm not as well versed in the program. I hope a kind person may be able to guide me on the way since Google currently is not my friend. I have a wav file in the link below, where there is a human voice and…
user3338501
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14
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7 answers

artifacts in processed images

This question is related to my previous post Image Processing Algorithm in Matlab in stackoverflow, which I already got the results that I wanted to. But now I am facing another problem, and getting some artefacts in the process images. In my…
user261002
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12
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2 answers

Remove known audio output from microphone input

I'm trying to learn how to work with audio in as many different ways as possible. Given a known audio stream (lets call it stream1) and an unknown audio stream (stream2) which are mixed into one single stream (mix1). Now assuming that we know…
m3z
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10
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2 answers

iPhone SDK: How to record voices with ambient noise suppression?

Can anyone point me in the right direction on how I would minimize ambient noise while recording someone speaking using the iPhone SDK Core Audio? I'm guessing a band-pass filter that eliminates any frequencies above and below the human vocal range…
memmons
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8
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2 answers

removing noise in a binary image using openCV

I had read in a video into Visual Studio using openCV and converted it to grayscale then used the function CV_THRESH_BINARY to convert it into a binary image. However, there are holes and noise in the frames. What is a simple way to remove noise or…
sue-ling
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8
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2 answers

How does noise cancellation work in android?

I came across this relatively old post which describes how impressively Nexus One's noise cancellation works and I was wondering where can I find more information about its implementation in the OS software. In particular: How much of it is done…
Android Eve
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8
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1 answer

Android active noise cancellation

I'm working a somewhat ambitious project to get active noise-reduction achieved on Android with earbuds or headphones on. My objective is to record ambient noise with the android phone mic, invert the phase (a simple *-1 on the short-value pulled…
Raevik
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7
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3 answers

averaging mask and laplacian mask in image processing

in a given application I apply an averaging mask to input images to reduce noise, and then a Laplacian mask to enhance small details. Anyone knows if I Would get the same results if I reverse the order of these operations in Matlab?
Glove
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6
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3 answers

How to remove gaussian noise from an image in MATLAB?

I'm trying to remove a Gaussian noise from an image. I've added the noise myself using: nImg = imnoise(img,'gaussian',0,0.01); I now need to remove the noise using my own filter, or at least reduce it. In theory, as I understand, using a…
shwartz
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6
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2 answers

How can I do audio noise reduction programmatically?

I'm developing an iPhone 4 (iOS 4) application that show an level meter. This app measures human voice. But it has a problem. When there is a lot of noise, it doesn't work. It measures also background noise. To measure sound, I use this: - (void)…
VansFannel
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6
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1 answer

C# Adaptive Sound Cancellation

At my work the entire engineering department just got moved into a new seating arrangement that allows sound to travel a bit more than any of us care to enjoy. I wanted to try to come up with a way to solve this in a cool engineering fashion. Is it…
kenetik
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