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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ROIs in Digital Micrograph EELSspectra behave strangely after command "EELSSubtractPowerlawBackground()" - Bug? (GMS 2.3)

When I run the script below on a DM EELS spectrum that already contains background and signal ROIs, it is ok if I don't show any images. ImageDocument imdoc = GetFrontImageDocument() image i0 = ImageDocumentGetImage(imdoc,0) image subt =…
Mike Walls
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Geometrical transformation of a polygon to a higher resolution image

I'm trying to resize and reposition a ROI (region of interest) correctly from a low resolution image (256x256) to a higher resolution image (512x512). It should also be mentioned that the two images cover different field of view - the low and high…
tehm0n
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Detect color in the middle of image (OpenCV, Python)

I have these 3 images (consider "image" the whole square not only the figure inside - this is just for demonstration purposes): What I want to do is detect the colour in the middle (center) of each one. So, having an area (square or circle) in…
lucians
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Iterate over regions and take mean pixel value in OpenCV?

So Im basically trying to divide up a gray scale image (in this case 32x32) by resizing the initial image. Once the "regions" are divided up, I need to take the mean pixel value of each one and then add to a string a 1, 0, or X. For example:…
CrowHop
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How to get the Daily Income data of masternode

I am going to calculate the daily income of masternode, but I am a new in this field so I don`t know how to get the data from which. I am going to obtain them using transaction history(They are provided from API), but I am not sure I am correct or…
Eric Lee
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Lines drawn around Region of Interest (ROI) using OpenCV

The role of this program is to draw Houghlines on an external window, when lines are detected in a game. However, when I implemented the ROI to avoid having useless lines detected, the border of the ROI is still detected as a line (obviously it…
hurkaperpa
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Finding image area covered by balls using wavelets

I have an image of pellets (balls). I need to find part of image, where balls are. My testing image looks like this: I have an idea using wavelets. In 1D, ball could be quite well recognized by Continuou wavelet transform. Here is example 2D…
google2
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Finding ROI in image using wavelets

I have an image obtained by phone camera and I need to find regions, where balls are. An image can for example look like this: I tried segmentation, but results are not as good as I would like. My current idea is: In 1D, when i have ball, I can use…
google2
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Find Contours inside ROI

I was searching for this question and haven't received any specific answers. I am already finding my contours and also i have defined my ROI. QUESTION: How can i find these contours only inside my ROI? I have defined my ROI at the beginning. Here is…
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corner coordinates of rectangular pyqtgraph roi

Suppose you have a rectangular pyqtgraph roi instance with some data: import pyqtgraph as pg from pyqtgraph.Qt import QtCore, QtGui import numpy as np data = np.random.random(size=(50,50,50)) app = QtGui.QApplication([]) w = pg.ImageView() roi =…
a.smiet
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How to use the integral image to detect intensity changes inside a ROI?

I am researching about ways of detecting changes in grayscale levels in images, but only working within a certain area of them, and I have come across the integral image. I think it can be used for this, just selecting an area from the image and…
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Tensorflow, probability of predicted value (ROI)

I've got your same problem, Tensorflow, probability of predicted value? but i use the predict 2 and i don't know how to print the percentage(confidence level) of a prediction. My question is, i can reuse you're code (or part of it) in mine? Or how…
Riky Proti
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Selecting ROI for high resolution images with Qt and Opencv

I am working on a project that involves selecting an ROI from high resolution image(more like 5187x3268 like that). Right now i am using findContours in OpenCV to detect a round object(since hough circles is kind of slow for high res images). The…
the_parzival
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Extract image from ROI (OpenCV)

Given the following code (python)... # Import the modules import cv2 from sklearn.externals import joblib from skimage.feature import hog import numpy as np from scipy import ndimage import PIL from PIL import Image # Load the classifier clf =…
Riky Proti
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Use ROI to find a ball (Python/OpenCV)

As described here: Tracking white ball in white background (Python/OpenCV) I need to track a white/black ball on a white field. The problem is that the functions in OpenCV are not 100% accurate, that's why I need to use an algorithm to find if the…
Aziz zeGeek
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