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1
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1answer
38 views

Thresholding a difference image with a very high kurtosis

I have an difference image produced by substracting two images of a certain location taken a two different time steps. The resulting image of this operation shows a histogram with a very large peak ...
0
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0answers
30 views

What are the various techniques for detecting Walls in the Building(Architectural) floor plan Images?

I have to process building floor plan images to extract Walls from the structure. It is trivial in case of binary images; but the images in our case are colored, and each have different color of ...
0
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1answer
60 views

Otsu Thresholding : Why 'minimum within class variance' gives the optimum threshold?

I was trying to understand the Otsu thresholding algorithm in image processing. For that purpose I found a useful link. I got the algorithm flow, but a fundamental doubt arises. Why 'minimum within ...
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0answers
93 views

GLOBAL THRESHOLDING using histogram

There is a recursive way of finding threshold in the image using histogram that are biomodal, and is as follows: An automated procedure for bimodal histograms : Select an initial estimate of T ...
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0answers
85 views

Shifting of Shift-Invariant Wavelet Transforms

Main Question: Why would iterative wavelet/inverse-wavelet transforms cause a shift along the x-axis for undecimated (shift-invariant) wavelet transforms? I am attempting to remove backgrounds from ...
0
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1answer
41 views

make a treshold frequency based on persentage of frequencies less than that?

Using MATLAB signal processing toolbox, I have created signals like dirichlet, chirp and etc and and obtained their fourier and cosine fourier transform. Now I want to find the frequency where for ...
2
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2answers
154 views

Iterative Hard Thresholding python implementation [closed]

I'm trying to implement the Iterative Hard Thresholding recovery algorithm for compressive sensing in python. It is a very simple algorithm, given $ \mathbf{y}( = \mathbf{A}\mathbf{x}), \mathbf{A}$, ...
1
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0answers
42 views

Thresholding for Movement Classification

I have an application which creates a Gaussian model of the background based on consecutive frame difference and auto-generates a threshold for separating no-changes to movements. The application ...
3
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1answer
328 views

Onset Detection Peak Picking

I have a guitar music signal and I want to detect the onset points via energy. This is the signal example: This is the energy plot: My question is what would be the best method defining the ...
0
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1answer
34 views

Scaling down the modal value when thresholding

I have a piece of code that I am translating and I am trying to understand the reasoning behind it. The application here is thresholding medical (cellular) images. The function in question takes a ...
6
votes
1answer
360 views

Deblurring algorithm to precede thresholding - speed over accuracy

I'm writing an app that recognizes Sudoku puzzles from a camera input. I'd like to remove camera blur from the images to improve recognition. Here is an example image: Since I'm processing a ...
0
votes
1answer
91 views

Image thresholding while retaining “underneath” contents

I have sample images, and I need to extract certain features that depend on color. Images are more like line art, contours, and consist of various line forms, and several colors. I can extract ...
5
votes
1answer
181 views

Adaptive thresholding based on number of pixels

I'm thresholding an image where the threshold value is a count of the pixels such that for instance if the threshold value is 100, any color value which has less than a 100 pixels is classified black ...
7
votes
1answer
251 views

White Road Sign Detection [duplicate]

Possible Duplicate: How to extract traffic signs from a photograph? I am working on a project which involves detecting north american speed signs (black/white) using a 720p HD camera. My ...
2
votes
1answer
127 views

Will binarization / thresholding of image yield better results when performed in a linear color space?

All thresholding algorithms I have read about make no mention about color space, except sometimes using pixel values between 0 and 255 as an example. But since the intensity output by a monitor of a ...
9
votes
3answers
347 views

Segmenting pills from the background

I just recently started out with Image processing and taken up a course related to it in Grad school. But I already have a project to do without too much information about the subject, however I've ...
5
votes
1answer
244 views

DCT and hard thresholding

If I have an Image and i find the DCT and then apply hard thresholding on the coefficients and then IDCT then I have attenuated the noise. Can someone please explain in detail or point me to the ...
16
votes
2answers
8k views

What are the most common algorithms for adaptive thresholding?

Adaptive thresholding has been discussed in a few questions earlier: Adaptive Thresholding for liver segmentation using Matlab What are the best algorithms for document image thresholding in this ...
6
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2answers
2k views

Otsu binarization with value preservation

I'm trying to implement a modified version of the otsu binarization algorithm. I'm trying to binarize document images. But in the binarization procedure I want the object (in this case the text) to ...
7
votes
3answers
350 views

Determining optimal binary decision rule threshold from observations with unknown priors?

Given only observations of a binary signal perturbed by Gaussian noise with unknown prior information, how can I estimate the optimal decision threshold? ( No, this is not a homework question) ...
5
votes
3answers
3k views

How do I compare two resultant images from different binarization algorithms?

I have a binarized image to which i add noise and then try to filter out the noise using various thresholding algorithms such as otsu and niblack.How can i compare the resultant image with the ...
8
votes
4answers
677 views

How to do De-Houghing of a Hough transform'ed Image?

I'm working with code found at Rosetta Code for creating a Hough transform. I now want to find all the lines in an image. To do so I need the ρ and θ values of each of the peaks in the Hough space. A ...
22
votes
3answers
3k views

Best way of segmenting veins in leaves?

I have done a lot of research and found out methods like adaptive thresholding , watershed etc that can be used of detecting veins in leaves . However thresholding isn't good as it introduces a lot of ...