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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How can I create a RoI pooling layer in tensorlfow/keras?

I've programmed a VGG16 based CNN and now I want to create a faster R-CNN from it. In all the architecture photos I've seen it is needed to have a RoI pooling layer but I don't know how to implement one. Is there an function to do this?
Intonet
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How to overlap the ROI into the original scan image in python?

I have two medical images. One is the "scan image" and the other is the "region of interest" (ROI) of that scan image. Now I need to overlay on top of the other. Here is the original scan image. Scan image ROI image How can I overlay, such that…
Mass17
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Assigning color to the region outside of roi in image in opencv-python

I have to make the outside region of roi as black color. I have been stucking with this for days! Thanks in advance :-) In the below image I want to make the region outside the rectangle as black color, so how it can be done using opencv ? roi in…
santhosh136
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How to improve the dynamic detection of the center of region of interest

I have MRI images grouped in 3D array shape(2D and slices) the images come from different machines so the spatial resolution is different from one to another, I do like to cut a ROI from all of them dynamically. The cut will be depending on the…
Bilal
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PCL:: CropBox doesn't work, means it doesn't filter the points I want to

I would like to find out what I am doing wrong. Steps Load .pcd inout file Limit that input file as follow typename pcl::PointCloud::Ptr cloudROI (new pcl::PointCloud); pcl::CropBox
user11967010
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How to draw bounding boxes on ROI using opencv

This is the image: And these are the key-value pairs in a text file: camera: LG G3 D855 reading: 05501 position: 843 1492 572 119 digit 1: 855 1513 54 98 digit 2: 971 1512 61 100 digit 3: 1092 1512 61 100 digit 4: 1207 1501 64 99 …
meu
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Google Sheets Calculate ROI in days

im trying to calculate the ROI in days for a specific case. I start an investment amount with value X and every day i get different profits. All this separate profits get added everyday until the amount of the investment X is reached. The output…
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OpenCV4 locateROI / Offset in Python

I'm trying to select the roi offset in a image in opencv 4.2, but i don't get it working. (I'm doing a recognition in the roi and want to mark it with a line in the original image.) I thought that I could use on "roi" in the following code the…
f4bi4n
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ROI extraction from Opencv Videoframe

How to extract ROI from an OpenCV Video frame? I have developed a code for tracking and counting system. I need help in implementing some more logic in my code. Help Required Section: Extract the images of the object when it crosses the Reference…
shantmanu
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OpenCV assertion error problem with Rois by blurring

in the lower code section I want to blur the rectangles of a face recognition with the help of the function Gaussianblur(frame(roi)). void drawPred(int classId, float conf, int left, int top, int right, int bottom, Mat& frame) { //Draw a…
deptrai
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How to calculate the area of a roi applied on an image using python by a known distance of line segmenton the ground?

The length of the line segment(white color line) in the frame is known with respect to the ground
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Is there any way in Python to let a user select bounding box (from mouse clicks) of the windows region?

Let suppose a bounding box should be the output (x,y,x+w,y+h), such that x,y is the point clicked on windows screen area. And then keep holding, drag and leaving click will determine x+w,y+h. Please help me. Thanks in advance!
Trees
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Roi custom OpenCV

I have a video stream where I do the detection of people using Opencv and python. My ROI is rectangular, but I would like to make a custom shape as in the figure.
Márcio
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find original coordinate of a point in Cropped image

I have an image. Using opencv .selectROI to extract the region of interest without any rotation gives me: r=cv2.selectROI(myImage) ROI=[int(r[1]):int(r[1]+r[3]), int(r[0]):int(r[0]+r[2])] In the ROI new image, if given a point (x_new,y_new) how…
Totally New
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How to increase size of ROI rectangle to 100x100 if it's smaller than that?

I am detecting objects and sometimes the ROI area is smaller than the 100x100 and I want to use min 100x100 ROI area even if the object is smaller . I don't want to resize resulting cv::Mat because if the ROI is small area then it looks bad. It's…
Lisa
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