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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c# Image processing Detect - save and match ROI

I have a image processing project to work on it on C# with emguCV and openCV with Microsoft SQL Server. Our production line is like this; My products shows like this. I want to detect just the phone as ROI* and save it on my server. While the…
Guest
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relation between ROI and wavelet transform output in jpeg2000

Consider a single tile image. I read that ROI involves scaling the coefficients in matrix obtained after wavelet transform. My understanding is - we shall multiply ROI related coefficients by power of 2 so that they will have greater precision then…
user1371666
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How can I get information from circular ROI using dm script?

After making a circular ROI in an image, how can I get the information (average, standar deviation, variance) from that image region using script? Can I link the position in the ciruclar ROI with original image?
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How to denoise and extract ROI of binarised animal footprint images

I am currently working on an animal identification using footprint recognition project. My main task is to process an animal footprint taken from natural substrate and identify the animal the footprint belongs to. The first step is to preprocess the…
user6913557
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Tensorflow: how to install roi_pooling user_op

I read in this post by HediBy that this ROI_POOLING user_op implementation works: LINK I used bazel build -c opt //tensorflow/core/user_ops:roi_pooling.so to generate the so file (after installing tensorflow) But when I use tf.load_op_library to…
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How to use hog detector to Know if a preselected ROI is a person?

I want to use hog detector in order to know if a ROI is a person or not, I already coded a filtering technique allowing me to select ROIs that can contain a person. for instance this is what I'm doing: 1.saving my rois as rectangles 2.for each…
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How to convert ROI from/to QImage to/from cv::Mat?

I cannot properly convert and/or display an ROI using a QRect in a QImage and create a cv::Mat image out of the QImage. The problem is symmetric, i.e, I cannot properly get the ROI by using a cv::Rect in a cv::Mat and creating a QImage out of the…
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Calculate object area inside ROI in OpenCV

I want to calculate area of detected object (that blue marker I used) inside actual ROI. I mean one of those two rectangles that are my Regions Of Interest in Threshold image (which is black and white). How to calculate area of object (I think - sum…
ScriptyChris
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Clear (not crop) the non-ROI part of image in OpenCV

I have a Mat and I successfully cropped the ROI (lower-half part of image). But the problem is, I want the upper-half part of image to be blank(white in color) and the cropped image in the lower-half. Here is my existing code - Rect imgROI(0,…
FadedCoder
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OpenCV Image Matching

I have two images from a stereo camera of the same scene, but few different perspectives (imgLeft and imgRight). Now, I want to find a ROI (red rectangle in the image below) of the right image in the left one. I need to do this very fast, because…
user5671855
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Crop Image in Emgu.CV

I have ROI of the image and I need to create new image that would be subpart of image. How can I do that? (I want to make pieces an array of images, not rectangles.) Image img = frame.Copy(); pieces = new…
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How to Zoom in multi-axes in the same time in matlab GUI?

I have a GUI with two axes. The first one for original image while the second one is for interpolated image. First in my code, I use imrect to select part of the original image and then I crop that part using imcrop . After that I display the…
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How can I find the thickness of a ROI traced via imfreehand in Matlab?

I am faced with a task to take a ROI on an image that was traced via the imfreehand function and determine the thickness of that ROI, preferably at all points. Has anyone ever faced similar tasks before, or implemented something like the ImageJ…
Michael
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How to create rotated rectangular or polygonal ROI/mask?

Let's say i have the following image: And my region of interest looks like this: And i want to have the following result: How can i achieve this knowing that the ROI is denoted by four points: Point pt1(129,9); Point pt2(284,108); Point…
Apastrix
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Opencv unable to get ROI of highest intensity part

I have tried this code. import sys import numpy as np sys.path.append('/usr/local/lib/python2.7/site-packages') import cv2 from cv2.cv import * img=cv2.imread("test2.jpg",cv2.IMREAD_COLOR) gimg = cv2.imread("test2.jpg",cv2.IMREAD_GRAYSCALE) b,g,r =…