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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Is there a way to detect and quantify the missing area of objects in images?

I am trying to calculate the percentage of leaf damage using R. I am able to do the image segmentation and area calculation using the pliman package, following the vignettes:…
M Sandoval
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Number of non-zero pixels in a cv::RotatedRect

as the title says i'm trying to find the number of non-zero pixels in a certain area of a cv::Mat, namely within a RotatedRect. For a regular Rect one could simply use countNonZeroPixels on a ROI. However ROIs can only be regular (non rotated)…
joekr
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Determine if a point is within ROI with OpenCV

My objective is to determine whether a point resides within a ROI or not. I have managed to crop an ROI and can access its width and height like this width = roi.shape[0] #total rows as width height = roi.shape[1] #total columns as height However,…
Harrison Chong
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Using python to select an area of an Image

I am trying to select an area of an image to do some analysis on that specific area of the image. However, when I searched online, I am only able to find guides on how to select a rectangular area. I need to select an area that is drawn using my…
Ruven Guna
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OpenCV: Concurrent GetSubImage to extract a portion of an image

I've implemented a GetSubImage function in order to extract a portion of an image. I use SetROI, Copy, and ResetROI. But this not works when Parallel Tasks are using the same image because of the SetROI is not parallelizable. Any other way to…
J.CSF
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How to get the actual point when I touch on screen?

I am developing an android application where i can select region of interest(ROI) when i touch two points on screen. However, when i try to change the resolution of image, the thing goes weird. What it shows does not same with what i touched. Here…
Sam
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Which software development practices provide the highest ROI?

The software development team in my organization (that develops API's - middleware) is gearing to adopt atleast one best practice at a time. The following are on the list: Unit Testing (in its real sense), Automated unit testing, Test Driven Design…
Test Engineering Manager
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Proving the ROI of a technology?

How does one prove the ROI of a technology to their manager? The closest thing I have found to a document on how to do this is: http://www.agilejournal.com/pdf/Finding-ROI-in-Build-Automation.pdf There are formulas in this document, but I can't…
leeand00
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How to get array of region drawn with lasso selector?

I'm completely new to Python, but what I would like to do is to draw a region in an image and then analyze it. This shall be done inside a GUI. My program can now draw a region with Lasso Selector (thanks to…
Mianen
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Multidimensional ROI of Multidimesional cv::Mat in OpenCV

I'm using OpenCV in C++ to create a multidimensional mat (to use as an accumulator) over an image. I create the 3d accumulator like this: const int accumSize[] = {sx, sy, sr}; cv::Mat accum(3, accumSize, CV_64F, cv::Scalar::all(0)); I need to…
eculeus
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ways of copying an image into a rotated rectangle opencv c++

I work on Win7 x64, with openCV and Visual Studio 2010, programming in c++. I want copying an image (call it image) to a rectangular area of another image (call it RR_image). This area, however, is rotated. here is image: and here is…
Cristina1986
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Select a ROI (circle and square) in matlab in order to aply a filter

I am working on matlab and I want to do an interactive selection like you do when you use the function roipoly, but I want to select or a circle or a square. I already search for funcion to select a region of interest (ROI) like you select when you…
Pedro Pereira
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Define image ROI with OpenCV in C

I have a question about how to define a ROI with OpenCV. I know what the definition of the function cvSetImageROI but I want to know if is possible to define a ROI with OpenCV with a different shape than rectangle. For example, define a ROI in a…
edsonlp1
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How to make partial screenshot via ADB

Just for curiosity I'm trying to automatically control some app (simple game) which checks user reflex (similar dynamic gauge like in "Burrito Bison"). My approach was to capture game screen via ADB, analyze part of the screen and if some graphic…
voldi
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Activate/deactivate pixel based on predominant color

I'm doing a real time image processing at about 20 FPS. I'm trying to filter 3 colors (using opencv, python). Those are: red, blue and yellow from a frame in which the light is not always constant (meaning sometimes the ambiental light can make my…
Cătălina Sîrbu
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