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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selecting multiple ROI in an image

hey guys i am using opencv 2.4 with python 2.7 on ubuntu14.04 I want to select multiple Region of Interest in an image is it possible to do so. I want to do motion detection in only the area i have selected to do so any of the following theory can…
vasu gupta
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Best way to detect a light blinking from video footage via python

I have some video footage and wish to analyse when a light source blinks. The light source is at the same location, so should easy to work with the ROI. I'm used to working with python, but not very strong when it comes to video analyzing - don't…
Norfeldt
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OpenCV 2.4.9 function findContours() causes program to crash

The code looks like that: #include #include #include #include using namespace cv; using namespace std; int main() { Mat image, edges, src_gray, output; int…
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How to fill bounding boxes in image?

How to fill region inside bounding box with white and outside with black i? case of one bbx or many bounding boxes for one image.
matlab22
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which method is the best for finding region of interet for hand gesture recognition

I am testing several methods for finding region of interest in hand gesture. in opencv for example I found some methods like camshift (for tracking a interest object), some background extraction methods (MoG, MoG2, ..) which specially are used in…
Maryam
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Select ROI in equirectangular image

I want to apply some image processing operations on an equirectangular image. (shown below) For this purpose i want to select a region of interest such that the half circles on both ends (represented by green color) should be discarded whereas the…
Saleh
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How to extract the text part only from an image using opencv and python?

Here is the image after the Pre Processed of a water meter reading... But whenever I am using tesseract to recognize the digits its not giving an appropriate output. So, I want to extract/segment out the digits part only as an region of Interest…
Ankit
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OpenCV detecting ROI, creating submat and copy to original mat

i'm trying to gray the faces of all people in an image. While I can detect their faces and gray them into smaller mat(s), I'm unable to 'copy' the grayed faces to the original mat. Such that the end result will have a mat with all faces in gray. …
adhg
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how to set region of interest?

Right now I am trying to make a movie, whose size is 640 x 480(4:3 aspect ratio).And I am editing a composition whose size is, 1024x1024, 1k resolution, and I want to make a proxy of this 1k compositon, but I want to make the proxy size 640 x 480.…
yzahiri
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Building OpenCV3.1.0 error: use of undeclared identifier 'selectROI'

Building OpenCV 3.1.0 from Github. Which fails when it comes to compiling the tutorial example: features2D. First, it complaint it did not find #include //for ROI So, I added video: #include
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Extract set of mat from another mat with OpenCV

I'm new in OpenCV. I want to know how is posible to extract a set of Mat from a original Mat like next one: As you see on the image, I divide the Mat in different regions. Now I want to get the different "subMats" or regions individually. My…
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Error ROI image in OpenCV

I have a binary image with some noise. I want to reduce the noise by using a rectangle size(10x10) sliding along the image. If the rectangle consists of more than 20 nonZero pixels, I will copy ROI to the destination image. for (int i = 0; i <…
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MATLAB: applying filter to ROI or mask in greyscale image

I have a greyscale image (I), and would like to apply different filters to different regions of that image in matlab (R2015b) (random and irregular shaped regions). I have a binarized version of what I would like the first filter applied to…
user3470496
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MATLAB Brush and Region of interest data

In MATLAB 2014b, using the brush tool on the figure, I can create a rectangular region of interest. The coordinate X and Y are updated while holding the left-click button of the mouse. When I release the mouse, is it possible to retrieve the last X…
oro777
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ImageJ if statement won't execute roiManager("Select",#);

Finally got my code working except for one if statement that I cannot fix. I am selecting ROIs 3 and 4 in the first step, and then if the "if" statement is satisfied I want to select just the 4th ROI and delete that. For whatever reason it skips the…
user3470496
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