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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Change the color of selected ROI in an image

I have an image shown as below, I choose three region of interest (ROI) labeled by the red box and I want to remove all yellow colors and replace them with white color (background color). My code is, a=np.copy(img) a[0:0,…
Jeremy_Tamu
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Cropping snippets from a image on the basis of coordinates from csv file

I have image which comprises of several cells (like any general form). I was provided with coordinates in csv file which have roi of part of image which i need to crop and save it as a new file with the image file name as folder name and the…
Aks
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How can I select ROI in a separate image in opencv-python?

I'm using python 2.7.13 and opencv 3.4.0. I have a videostream with 2 green dots. I'm tracking them using color detection. I need to select a two ROIs(region of interest), each of which will contain one dot, in two separate images for further…
J Dow
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Quality vs. ROI - When is Good Enough, good enough?

UPDATED: I'm asking this from a development perspective, however to illustrate, a canoical non-development example that comes to mind is that if it costs, say, $10,000 to keep a uptime rate of 99%, then it theoretically can cost $100,000 to keep a…
Troy DeMonbreun
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Python OpenCV: Obtain the region of interest on an RGB image

So, I'm fairly novice to OpenCV, but I've done lots of searching and don't think I can find the solution anywhere online. I have a three channel RGB image that I would like to find the ROI of. To clarify, everything but a small rectangular subset of…
Polyrogue
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Histogram of a region of an image

I want to get the histogrm of a region in a numpy image in python. I found a solution on how to use a mask here. this solution didnt help me because if i use it I will loose the real number of black pixels. Also, the region that i want to get is not…
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Compare cropped images python opencv

I want to compare two images to check if they are equal or not, but for that i need to compare a specific region (ROI) of both images. I've cropped the areas i want to compare, but now i would like to know how can i do that process, because i can't…
vallete7
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Tableau - Display last number in a window calculated list as a text label to be presented as a headlining number

I have a window calculated list in Tableau [img 1] that is the accumulation of savings and costs over months based on a number of parameters that calculates my ROI. I want to take the last number in the column shown and use the value as a headline…
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Taking ROI of a MR image and get the mean intensity of that ROI

We are doing a laboration study and we want to take a ROI (decide an area in the image) of the bottles in the MR image using MATLAB to get a mean intensity value. We have tried roipoly, a function in MATLAB, but the thing is that the output will…
Mazz Ebra
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Capture area of interest

Using OpenCV, how can I draw a similar interface and, caputure the ROI inside it ? How this is called ? It's a opencv mask ? I would like, more than code, know the terms/steps I have to search to achieve this.
lucians
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Masking image and video in opencv c++

I am a beginner in image processing especially in openCV C++. I have a problem on my work. In C# with EmguCV it is possible to make masking in image and video files based on ROI. My question is, is it possible to make masks the same way in OpenCV…
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Image analysis with Roipoly. Getting ValueError

I have been trying to use RoiPoly to draw a ROI and find the mean pixel grey value inside a ROI in the image. However, I keep getting the following error: Traceback (most recent call last): File "example.py", line 22, in
Ruven Guna
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Apply function to masked region

I have an image like that: I have both the mask and the original image. I would like to calculate the colour temperature of ONLY the ducks region. Right now, I'm iterating through each row and column of the image below and getting pixels where…
Reine_Ran_
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python + opencv: how to extract a ROI of unknown shape and analyse it?

I have an issue which I can't work around since I'm not very fluent with python and opencv. Suppose I have an image, I convert to grayscale, I threshold it, perform some dilate and erode and finally I am able to retrieve a list of contours. Some…
gabt
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Measuring the length of a fraction of a pixel

I have a disk that I want to cut it in wedges, just like a pizza, I did this with ImageJ, Disk but as you can see in the picture, there are some pixels that has a fraction inside a ROI and the other fraction inside the other ROI. Fractioned…