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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OpenCV C++ set ROI from a rectangular area

Anyone know how to set ROI based on image bellow? I used Hough Transform to detect the white line and draw the red line into the image. What I need to do is to set the ROI in the rectangle. Since Hough Transform unable to get location of each…
user2649244
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Filling a specific region with a colour

As a follow up to my question here, I want to ask if fill could work? I just didn't figure out what would be the values of X and Y be provided the question shown in the link.
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Using imfreehand within your program

For instance, I start my program as follows reading some image: I=input('image name: ','s'); img=double(imread(I)); I'm planning to work only on some portion of that image. So, I noticed that I may need h=imfreehand for this purpose. Thus, I have…
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to draw ROIs and to calculate mean difference

I have two CT image . How can I draw multiple ROIs on both image and calculate mean difference between each the corresponding ROIs with matlab ? I've used the 'imrect' or 'imellipse' but this commands creates the Mask which makes the image as…
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Runtime error message Index was outside the bounds of the array. for Visual Basic 2010

I am computing the ROI with a moving rectangle and extracting the ROI to compute the standard deviation, mean, area and Pixel value coordinates X and Y in a seperate form2 by clicking the mouse. At this juncture I am trying to pass a function from…
dirty_sanchez
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How to overlay a RGB ROI on top of a Greyscale Image in a GUIDE Axes?

I am trying to figure out how to overlay a RGB ROI on top of a Greyscale image. I am able to accomplish this using a figure. Here is my code for accomplishing this. mask=map>0;%map is the ROI im =im2double(dicomImage); …
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Setting roi to eyes and mouth only in camera capture and further processing

I am making a drowsiness detection system. so for that i want to set the ROI of the camera capture to eyes and mouth only and i further want to note their characteristics. i am able to set the ROI manually but i want the ROI to be set automatically…
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Fix Size ROI for all images in Matlab

I have multiple images and I am using imcrop function to take ROI in image. The problem with imcrop is it gives me different size of ROI on each image. I would like to take ROI of same size for each image. There is a option in imcrop by which I can…
user2179080
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Setting a rectangular ROI given a centre pixel value using OpenCV in C++

I am am trying to create a rectangular ROI on an image with the location of a certain pixel being the center of the rectangle . How should I go about doing it ? image=…
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Detecting when a face enters ROI in opencv

I have a face tracking program that reads video from a camera and draws a rectangle around the persons face. What I want to do is have the program recognise when the face enters a particular region of the frame, and initialise some other action.…
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ROI info in DICOM Images using Evil Dicom

Currently I am able to open, display and do some image processing on DICOM images. I can also use the mouse to draw polygons. Can someone give me an indication on how I can make the inside of the polygon 1's and the outside 0's. What I would like to…
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Why my OpenCV ROI does not change?

I try to loop on an image to create several ROIs (their number can be changed) but it appears that the system can only chose one. I need that because I will try to make a LBP face detector. Here is my loop and the displaying (it's the forst time I…
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how to Extract rois as induvidual roi images

I have an image that contains more than one rois //non-rectangular// in a transparent image.. plz help me how to extract those rois as induvidual roi image
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examine the pixel values of certain region of Interest in an image through 'statement'

I need help with a trivial problem. I have an image in which i defined a region of interest in that image. now i want to examine the pixel values of my ROI, so that if the ROI color range e.g.between (105,105,105) and (255,255,255) then print 'left'…
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How can I draw a rectangle from the points I want, using ROI?

Hello I am beginner in OpenCv. I have a maze image. I wrote maze solver code. I need to get the photo like the picture for this code to work. I want to choose the contours of the white area using ROI but I could not When I try the ROI method I get a…
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