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 Region of Interest

I have a program that detects a face when the the web cam i recording. I've created a region of interest and i want to only detect faces only within the roi. Im trying to instruct my program to operate only in that region. Have no clue how to cap =…
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How to calculate return of investment in powerBI using DAX?

Hi everyone, I have 2 columns as shown in the screenshot above, Date and Cumsum P/L. I want to calculate the return per month by using this formula: (Last Cumsum P/L of the month - First Cumsum P/L of the month) / First Cumsum P/L of the month For…
weizer
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How can i use Viola Jones Algorithm to detect the Face as a region of interest and crop it till the rectangle box?

I want to detect the face in the video frame and remove the other elements such as background etc. and just want to focus on the facial region, for this i need to use viola jones algorithm, czn anyone give me a hint or suitable answer for…
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How to check if X,Y coordinates fall within the range of a rectangle in python

I have a 1920x1080 monitor and some X,Y coordinates (black dots) based on the Cartesian coordinate system (center of the screen=0,0). What I want to achieve is to check whether any of these X,Y coordinates fall within a prespecified rectangle region…
Phoenix
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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
Bharath Kumar
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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'…
Khaled
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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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Python 3.6 OpenCV real-time capturing and processing

I am in the process of making a Real-Time feedback program using Python and OpenCV: a webcam will be observing a process and generating feedbacks based on what is happening. Here is my code: points = get_points_xml() rect =…
Athylus
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How to select ROI in binary threshold area using opencv in python?

I'm trying to crop the image from the binary image which is already processed from the original, suppose I have the original image and I got the binary image from the original and I want to crop the image only the white area using blob…
Alpha9
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Define region of Interest in image file to crop/scale dynamically

I am looking for a kind of tool that gives me the possibility to define a certain region of interest (ROI) (maybe a rectangle area) within an image file. The ROI should be stored somehow within the metadata of the image. Further I am looking for a…
Hape
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imfreehand data type issue

I'm using imfreehand in my program, and when I came to erosion, I got the following error (I didn't paste the whole error): Error using imerode Expected input number 1, IM, to be one of these types: numeric, logical Instead its type was…
Simplicity
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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…
Adolf
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How to extract region of interest after watershed segmentation algorithm in matlab

I have applied watershed segmentation algorithm on occluded leaves and found out the region of interest (ROI) for a single leaf. The regions have been labeled with different colors, as shown in the image given below. Now the main task is to extract…
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How can I get the ROI frame in the full frame?

I try to play a ROI of the window as shown in the picture by receiving the image with the Webcam. - Conditions 1) The size of the main window is 400x300. 2) ROI is set to 320x240 at (30,30). 3) Put a red border on the ROI. enter image description…
Joon
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function call rect for roi

Mat img1 = imread("hello.jpg", 1); Mat img2(img1.rows, img1.cols, CV_8UC3); img1(Rect(0, 0, 200, 200)).copyTo(img2); I am learning opencv using c++. but I don't understand the syntax that img1(Rect()). From my understanding, for…
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