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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

441 questions
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OpenCv : draw a white filled polygon

I'd like to draw a white filled polygon, with arbitrary angle, in a black IplImage. I know there exists function such as createCircle, but I can't find something similar for polygons. I found this , but the use of it is awful, I mean I shouldn't…
CTZStef
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identifying code improvements

We've just gone through a pretty major system rewrite and I have been asked to find and identify areas of the code that have been improved. as a way to justify to the customer that the effort we've spent was worthwhile. Identifying the areas isn't…
Shane
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My circle detection opencv program which calculates flow rate is getting stuck on an IndexError: "index 1 is out of bounds for axis 1 with size 1"

My program is supposed to use circle detection in order to detect droplets falling through the drip chamber of an IV setup. It's then supposed to calculate the flow rate per minute based on the number of circles it detects. I got this code from a…
Crim
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Create tensor with a single ROI from cv::Mat and cv::Rect with OpenVINO API 2.0

OpenVINO API 2.0 changed how images are preprocessed. Documentation describes an overload used to construct a region of interest tensor from another tensor. Tensor(const Tensor& other, const Coordinate& begin, const Coordinate& end) I found a brief…
Jared
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Finding number of ROI Groups entered into Roi-Group Table plugin

I have been using the Roi-Group Table plugin, which i have cited at the bottom of this post. I am writing a macro and need to get the number of groups that were entered into the plugin, so that I may enter them into a loop that sequentially leads…
Sharon Daniel
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error occurred when binarization based ROI algorithm with OpenCV in JAVA

when implementing ROI algorithm to binarize images in JAVA by using OpenCV，exception threw. can anybody help me figure out bugs among my code snippets? System.loadLibrary(org.opencv.core.Core.NATIVE_LIBRARY_NAME); String filename =…
biotech7
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using try except with itk on OTB

I want to extract ROI of Sentinel 2 images, several of them aren't on my ROI. I have treatment to do afterwards in the same loop; for it to be faster I'd like to pass to another image if the error : 2020-02-12 12:06:10 (WARNING) ExtractROI: Could…
sam
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Divide the region of interest into blocks

I am working on image breast cancer classification using Deep learning. I want to divide the region of interest (ROI) in the image into multiple blocks. The dataset contains 1000 images of the right and the left breast as show in Figure 1. First, I…
Eda
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Optimisation problem to maximise profit of fleet allocation given profitability matrix of plane type to route & constraint of block hrs

I am trying to create an optimisation algorithm to allocate plane types to most efficiently to my routes for fleet optimisation. My input: a 150 x 6 matrix, with 150 routes which must all be flown, and 6 possible plane types, with the variables…
Sarah
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How to extract values from all voxels in a mask using FSLutils?

I've created a mask for a brain region of interest (2D 3x3 voxel square) and use that mask to extract values from different maps (i.e. FA map) of the whole brain. With fslmaths and fslstats, I can extract the range of values within my mask, mean…
Eva
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Extracting highest level of nested segments from a contour plot in Python

I am working with a contour plot in Python and each nested segment of the plot represents a region of interest (ROI) for me. I would like to extract the highest level of the nested segments in a pythonic way. Please find attached an image of the…
Mario Bernardi
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Problem with NumPy Arrays when creating Face Filters

I am currently working on a project where I detect a face with a haar cascade classifier. In the code, I have created Rois with a cv2 rectangle and the goal is to apply images to the ROI. On some images the code works on others it doesn´t, also…
hubermann
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How do I target a specific area for HoughLinesP in OpenCV?

I'm trying to target a specific area of a video so that the HoughLines don't show up on other parts of the video. I don't know how to do this but here is my code so far: import cv2 import numpy as np import window_names import…
Isaac_E
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Using a live stream instead of video file in this Tkinter Code

I need to select the ROI of a video stream in my Tkinter application. This code fits exactly my needs: https://github.com/anandpr1602/TKinter_ROI_Frames_Selector Except it uses a video or collection of images as source. As I'm new to Python and even…
Daniel do Amaral Denardi
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Adding a border around Region of Interest using python

I have a code which takes images from a folder, crops the region of interest around it using the ROI function, and then removes the background using the rembg library. But I want a border around that image, around that specific object itself, like…
Atharav Jadhav
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