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Questions tagged [threshold]
715 questions
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Count time intervals for events greater than threshold
I am stuck at something in MATLAB and would appreciate if someone can help. Here is what I would like to do. I have a velocity field data w.r.t. time (see figure attached).
I would like to count number of time intervals (T1,T2,T3,etc) for which…
turbflow
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Image processing : Improved thresholding?
I would like to apply a rotation on image of scanned book.
I use FindContours and approxPolyDP to get the corners of the book and for that I need a perfect white square. Only, when I apply a simple threeshold:
threshold(imgGrayScale, three, 1, 255,…
Guillaume Andreani
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Canny edge detector with a single threshold value
I'm trying to port some Matlab code to C++.
I've come across this line:
edges = edge(gray,'canny',0.1);
The output for the sample image is a completely black image. I want to reproduce the same behaviour using cv::Canny. What values should I use…
protas
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SQL Server datetime and data redundancy
We have a faults table containing a column DATE_ACTIVE with a datatype of datetime2(7). Values in the this column are as follows:
2015-08-16 05:02:46.0000000
2015-08-16 05:13:25.0000000
We need to fetch records (faults) from this table which are…
Umakant
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Find start and end date of when value exceeds a certain threshold for at least X time periods
I have three columns, one of which contains a statistic, the other a critical value, and the final one the date. I would like to know how to find the start and end date when the threshold of the critical value is exceeded for at least n periods. A…
Simon
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Perl: Is it possible to subset a hash passing a value threshold?
Say I have a hash of the form:
%hash = ( a => 1, b => 2, c => 3 , d => 4 , e => 5 , f => 6 );
Can I obtain a subset of such hash passing a value threshold of 3, obtaining the following %subhash
%subhash = ( c => 3 , d => 4 , e => 5 , f => 6 );
and…
DaniCee
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Thresholding an RGB image
We have an RGB image. I want to apply adaptive thresholding on it. How can we find the threshold value??? I think we can separately find the threshold value of each channel but what next is the confusion?? or if you can provide some better solution…
Navdeep
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Thresholds in backpropagation
What is the use of thresholds in backpropagation algorithm. I wrote a java code for class label identification. I used some random thresholds (0-1) for the neurons. I trained the system and tested using some data.It worked pretty good. But what…
mRbOneS
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Removing rows of data in R below a specified value
I was wondering if anybody could help...
I have a data frame which includes a continuous time column and I am trying to remove all rows below a specified time.
The data starts from approx. 11:29:00 but I want to remove all rows before the time…
Student
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Image J spot segmentation
I am trying to use the spot segmentation plugin on an image the I have but whenever I carry out the plugin it picks up a lot of the background noise and I end up with the box with grey segments, where the large segments are what I'm interested in…
Zaid Malhees
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Highcharts variable threshold
Is it possible to set a threshold that changes across the series?
like the picture attached?
I already went through this link ( http://api.highcharts.com/highcharts )and couldn't find anything similar, only static thresholds.
Thanks in advance
Alejandro
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pre-processing to improve feature detector before tracking - Matlab
I am trying to make tracking for soccer player, I need to detect features from this player and then estimate the distance difference of these pixels over number of frames.
first I have to detect the main features of the player and then match them to…
user1217585
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Root Mean Square Error with Matlab
I have an image.How can I do RMSE?
I = imread('cameraman.tif');
Sonia
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Image segmentation with region-based thresholds in Matlab
I have a noisy image with multiple separated circular regions that are blurred out. An example of such image with six Region of Interests (ROI) is :
image source
Segmenting this image with global threshold is easy in Matlab using bwconncomp and a…
Ash3323
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