Questions tagged [roi]

Region Of Interest, a region of an image on which algorithms are executed on.

Region Of Interest (ROI) is a selected subset of a data set identified for a particular purpose and is commonly used in many application areas. The data set could be any of the following:

  • 1D data set: a time or frequency interval on a waveform
  • 2D data set: the boundaries of an object on an image
  • 3D data set: the contours or surfaces outlining an object (a.k.a. the Volume of Interest (VOI)) in a volume
  • 4D data set: the outline of an object at or during a particular time interval in a time-volume

Tag Usage:

An ROI on an image can be defined in different formats, like a , a or a set of . The tag is commonly used in question related to or . An ROI can be defined to:

  • Restrict the region of the data set that an algorithm is applied to and avoid unnecessary calculations. (e.g., in an )
  • Identify/Annotate a part of data set. (e.g., locate moving objects in )
  • Extract additional information from the data set. (e.g., measure size of a tumor on a medical image)

An Example:

ROI locates the boundaries of a registration plate (it's Persian), this area will be used for ANPR:

enter image description here

Additional Reading:

Region of Interest on Wikipedia

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Region of Interest in nighttime vehicle detection

I am developing a project of detecting vehicles' headlights in night scene. I am working on a demo on MATLAB. My problem is that I need to find region of interest (ROI) to get low computing requirement. I have researched in many papers and they just…
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opencv how to visualize a non-rectangular region (roi) in a performant way

I have an image (cv::Mat) and a ROI that can be seen as a mask. I want to show the original image with the ROI blended over it. My mask is smaller than my origiginal image: each element represents a block in the image. Suppose my mask is this (note…
Chris Maes
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Renaming ROIs in ImageJ based on their x coordinate value in order to create a sequence

After I few hours of intensive search, I need to ask you. So, I few days ago I was provided with macro that effectively creates ROIs based on radius and function (Maximum). Link My starting point is the following image:…
JerryTheForester
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Standard deviation of pixel values in a masked image

I have a DICOM image with a mask on. It looks like a black background with a white circle in the middle (area not covered and zeroed with the mask). The code for which is: import numpy as np import dicom import pylab ds =…
Foodaaaay
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ImageJ: How to put label names into results table generated by ROI Manager

I use ImageJ to measure length of different parts of biological organism. I draw straight or segmented line over image, add line to ROI Manager, and set name to it (rename the standard name of a label). After drawing some lines I measure them. The…
Ivan Z
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Continuous Integration ROI/metrics

I've been researching for while on data regarding benefits of CI. But I haven't found any solid data, there few threads discussing this topic example: ROI CI comparison-of-a-project-with-ci but most of them deal with abstract example: "Early…
PotOfTea
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Batch Processing Image Files in MATLAB

I'm a beginner in MATLAB and image processing. I encountered a problem while trying to use the batch processing and hope someone would be able to enlighten me. Thanks. Following the example from MATLAB, I did these: p =…
Veronica
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Custom Region of Interest

I know theres a similar question about this but mine is the continuation of this post. ROI in Video file I already find a way to get the ROI and is now running with my program but only in Rectangular(cv::Rect) Now, I want to get the ROI in this…
mabg
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OpenCV and Android: drawContrours from a ROI at correct position in image

On Android by using OpenCV I try to draw contours I got from a ROI but I am not able to draw them at the correct place at the image. Mat resultImage= ...; // source Rect roi = new Rect(x, y, widht, height); Mat mat = new Mat(resultImage,…
Paket2001
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Possibly a MatIterator_ error in a Region of Interest

I'm working with some object detection using OpenCV 2.4.4 with C++. Unfortunately those objects that I must detect doesn't have unique shape, but they do have some really specific color range in the HSV color space (right now i'm detecting some red…
gustavo-vm
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Get all the points in triangular ROI in a xy plane

Input: I have some 50000 points in a xy plane as shown in the below picture. Now, I need to get all the possible points in a triangular ROI. How to get it. It can can be opencv or Matlab. The below is the sample where I need to get the possible…
2vision2
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Get plot points indicies

If I need to get the indices of some plotted points on a figure or axe by using box selection like the following: load cities education = ratings(:,6); arts = ratings(:,7); plot(education,arts,'+') How to get the indices of these points in the…
Sameh K. Mohamed
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iPhone Objective C: UIImage - Region of Interest

Is there any way to get the min rectangle area which contains all the non-transparent part of an UIImage? Reading pixel by pixel to check where alpha == 0 ...isn't a good way I believe. Any better way? Many thanks for reading
Unreality
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How to obtain a contour from points with OpenCV

I'm trying to obtain a ROI from an image using VC++ and OpenCV. I managed to display an image, get the coordinates of a point when I click on it, store these coordinates in a vector and draw lines between these points on my image. Here is my…
alvinleetya
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Detection of parking lot lines and ROI openCV

I am working on a openCV project, trying to detect parking spaces and extract the ROI(Region of Interest) from an image for further vehicle detection. The image provided will consist of all empty parking spaces. I have read several posts and…
mojorisinify
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