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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get Original image from ROI image in opencv

is it possible to get back original image from image ROI? for example say we have cv::Mat image = imread("image.jpg", 0); cv::Mat imageROI = image(0, 0, 100, 100); myFunction(imageROI); and in myFunction I want to work with original image. is there…
Saeed.Torabzadeh
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ROI with SURF invalid argument

I have the following line of code: x=ginput(1); y=ginput(1); limits = [x(1) x(2) abs(x(1)-y(1)) abs(x(2)-y(2))] boxPoints = detectSURFFeatures(boxImage, 'MetricThreshold',100,'ROI',limits); And this gives the following error: Error using…
bcr
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Mat OpenCV Rect ROI: access violation

I am new to OpenCV image processing. My task is simple. I have to get 1/4th of an image (lower 1/4). The size of the image is 320 x 240. I used ROI Rect in a Mat object to get it. Mat img_roi; img_roi= image(cv::Rect(0,180,320,240)); I get the…
Karthik_elan
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OpenCv assertion failed

I am working on application for finding face in 2D image and later inside same image I want to find mouth, but I have some problem right now. This is my code so far: for (int i = 0; i < faces.size(); i++) { Point pt1(faces[i].x,…
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Image Cropping using Predefined ROI Matlab

Basically what I'm trying to do is using predefined ROI's to crop and image into multiple new images. Longer is that I have a map of brain, with sections of it defined. using that I define many ROI's from it in MATLAB using imfreehand or roipoly.…
Gbru
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Saving imfreehand ROIs in a script

What I need to do is predefine a lot of ROI within MATLAB using imfreehand and then put these ROIs into a script. This really isn't that hard as I can name them and just keep drawing. But the thing I'm lost on is how to save these ROIs within a…
Gbru
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Submatrix out of bounds (OpenCV)

I'm trying to divide an image into a grid, and save the individual pieces. At the moment I loop through the piece number and get a sub-image, which I then save. Can someone explain how to get the sub-images properly? I've been following similar…
Mirror318
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To convert a matix to vector in opencv

I have written a code for creating a matrix which describes the features in a video.I use ROI for cropping the feature in images and saved it in a matrix.The whole program is inside a for loop.Now how to plot these matrix using imshow.. Mat…
Sam M Mathew
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Opencv: zero pixels outside of region of interest with rotated rectangle?

I have a rotated rectangle representing my region of interest: [[634 547] [353 504] [436 -41] [717 1]] I'd like to quickly filter out all pixels not inside of that rotated rectangle. Note that the rectangle actually is beyond the bounds of the…
Wesley Tansey
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Cost of system integration?

On the software development projects that you have worked on, what has been the approximate cost (expressed as a percentage of total system cost) of system integration? System integration includes integrating with other software, databases, etc.
user128807
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OpenCV, dynamic modifying of webcam display

Sorry if the title gave you the wrong idea, I tried to make it as brief as possible. In short, what I am trying to do is detect a face with Viola-Jones algorithm (already implemented), save it in a separate image, convert that image to grayscale,…
MrLinjak
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Interrupting/Disabling ROI drawing functions in a GUI

I am programming a GUI for the selection of regions of interest (ROIs) in an image. Several kinds of regions may be chosen using built-in MATLAB functions such as impoly/imellipse. Below, I provide a minimal working example of a GUI where my…
fnery
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open cv, rectangle region of interest referencing

I want to create a rectangle with particular coordinates width and height from an image. And then splitting the channels and finally to thresholding the given channel in this area. My problem is I want to reference to a area (rectangle) on the…
user1844505
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Dilation Gradient w/ different ROI's (blob optimization) OPENCV

I'm working on a dilation problem in c++ with opencv. I've captured videoframes of a car park and in order to obtain the best blobs I came up with this. Erosion (5x5 kernel rectangular), 3 iterations Dilation GRADIENT (think of it like a color…
Bert Dewaele
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Copying a portion of an IplImage into another Iplimage (that is of same size is the source)

I have a set of mask images that I need to use everytime I recognise a previously-known scene on my camera. All the mask images are in IplImage format. There will be instances where, for example, the camera has panned to a slightly different but…
ha9u63a7
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