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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How to get each value of x,y,w,h in this crop image?

i want to ask something. In opencv there is cv2.rectangle to build a rectangle of object interest. After I got the object interest which is represent with rectangle, I want to get the region of interest box. To do that I used crop = frame[y:y+h,…
Ines
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Object Tracking on a video using bbox, opencv and python

I am trying to create an robot that can follow a human that I chose, for that I am usig raspberry pi with python and openCV. I want to create bbox around a human, and I want my camera to track that human, I found pieces of codes on internet and I…
Antonio
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Detect High density pixel areas in a binary image

I am doing background subtraction, and I obtain a binary image with foreground objects and with some noise. I want to obtain a ROI for each object on the binary image and them analyze it to ensure that is the object that I want. How do I segment…
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Applying an algorithm to a specific region of an image

I'm trying to apply an algorithm only to a specific region of an image. I tried imfreehand, but not able, at least for me, to do that using this function. So, is there some way when running my code for the operations to be applied only to some…
Simplicity
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How to extract and locate the specific region of image by using OpenCV?

I am a newbie to OpenCV. I would like to work on a small project for tracking the rotation speed of a gear (by using webcam). However, until now, I have no idea how to work on this. The posted image shows a machine which contains two 'big' gears.…
joe shum
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Region of interest extraction in MATLAB

I am writing a MATLAB code to implement a specific filter on a selected (from auto ROI) grayscale region of a forearm image which consists of veins. I also uploaded the forearm of a subject (after foreground has extracted). Basically, I have NIR…
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