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Questions tagged [threshold]

The starting point for a new state.

715 questions
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OpenCV Select Ink On Scanned Page

Say we have a picture of a page with text on it. However, a threshold is not sufficient. On an example image, the page has a large shadow that covers half the image, such that at some points, there is paper that is darker than the lightest…
Jacob Parker
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How do I apply a standard deviation threshold when calculating a histogram from signal data in MATLAB

I am calculating features from an EMG signal using MATLAB by segmenting the EMG signal into windows of 200 samples and then calculating the features of each window. I need help trying to use a histogram feature please. I can easily generate a…
humbleHacker
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Sharepoint List View exceed threshold but still able to see

UPDATE I acknowledged that the warning only show if the view has filter, count, sort... condition. A default flat view won't be restricted by threshold I am new to SharePoint 2013 and facing a weird issue. I created a List with more than 6k items…
Brian Pham
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Opencv 2 multi-threshold Otsu method

I know how to call binary Otsu method for a greyscale image: threshold(image, opencv_otsu_result, 0, 255, CV_THRESH_BINARY | CV_THRESH_OTSU); But I don't understand how to use this function if I want divide my image into 3, 4,... colors. I am…
Maxim Gotovchits
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How to classify images based on the amount of colors in the image?

I have a problem where all images have the same object; however, these objects can either have number_of_colors<=3 OR number_of_colors>3 and images are not labeled. My attempt starts by converting RGB to LAB and Consider only the A & B to find the…
Nawaf
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Count top elements in a matrix (Matlab)

I have the matrix: A=[ 4 0 0 0 0 0 3 0 0 0 0 0 2 0 0 0 0 0 1 0 0 0 0 0 1 ]; I want to get the top k elements' values in the diag, such that the sum of these elements are larger than a predefined threshold T, whilst k is as large as…
kgk
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How to thresholding image by ourselves without using fucntion in OpenCV

I'm new in OpenCV, and I want to thresholding the image by myself without using Threshold function in opencv, because the time spend on function threshold is to high for me. Here is my code: Mat src = imread("D:\\DataBox\\7.jpg", 0); for (int i = 0;…
HenryChen
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Applying threshold on both positive and negative elements of a matrix in matlab

suppose I have a Matrix like this: A=[-3 -4 -5 -6 0 2 3 3 4 5 8 9 10] Now I want to extract a Matrix whose positive value will be greater than 8 and all other +ve value less than 8 will be zero. And its -ve values will be less than -5 and all other…
sifat
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Threshold voltage for high and low in a BeagleBone

It is said that 0V indicates a LOW and 3.3V indicates a HIGH. I was wondering if there is a threshold voltage for the HIGH and LOW logic level. Tried searching it, but couldn't find anything. Thanks in advance.
Priyadarshini S
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Subtracting double from Mat in OpenCV, Java

I am trying to implement the threshold method, made with OpenCV, posted here. It is written in C++, so I am trying to rewrite it for myself to Java, for Android Studio. In the code here there is a line:res=1.0-res;. "res" is Mat (OpenCV matrix, the…
Dainius Šaltenis
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Better way to apply custom threshold in python

We know that we have thresholds in python, binary, inv binary, tozero, truncate and otsu, but problem with me is i want to apply first of all range threshold that is, i want to change color of pixels that are in specific range say, all pixels having…
AbdulMueed
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"assertion failed (m.dims>=2) in Mat" Raspberry Pi OpenCV

I downloaded a project which allows to get frames from Pi camera module with OpenCV. When I try to run the downloaded code, It works without a problem. I just want to apply simple trheshold operation on frames but I got the error shown below. I…
ffttyy
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Max entropy thresholding using OpenCV

I'm trying to convert the code for using the maximum entropy thresholding from this matlab…
Akash Lad
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Audio segmentantion

What I am trying to do is to "separate" vowels from consonants from an audio file (wav file). For example, a file would be this sentence: "I am fine" and I have to separate the vowel sounds from the consonants one. After the "separation", I can…
Lerul Ler
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OpenCV Template matching against video

Assuming I have a template image and searching for a match in a video,what is the measure to be looked for ? From OpenCV tutorial here 1.loc = np.where( res >= threshold) gives me numpy array.How to infer it on a scale of 1-100,where 100 refers to…
addcolor
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