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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Macro on imageJ, loop does not move to the next ROI

I'm trying to crop sections in an image and then averaging all of them. I'm recycling my previous macros on imageJ. Previous macros work well by doing loops in a list of ROIs. But, for this one, I can't understand why the loop does not move to the…
Jonathan Pacheco
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How to remove part of images around board - opencv

I am working with ROI and this center element is what I am looking for. But this part of image above I need to remove. smooth= cv2.GaussianBlur(gray, (3, 3), cv2.BORDER_DEFAULT) T, thresh = cv2.threshold(smooth, 32, 255, cv2.THRESH_BINARY) #roi =…
user1801745
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'drawcircle' and 'roi.cricle' do not respect preset Radius

I am trying to make a circular roi with a specified R,but allowing to set the center and the position. I first thought of doing it with 'ginput' and later drawing the circle, but since I need to allow for interactive reposition, I switched to 'roi'…
Tamara
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How to get the ROI for eyes to be a single rectangle

Hi I need help with the boundary of the eye roi since it is so to the left, to get it in the middle.A lot of examples for eyes are separated and/or in a circular shape. img = cv2.imread('man1.png') newImg = cv2.resize(img, (600,600)) #gray =…
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Create Mask Inside ROI selection

Hi I am trying to make the eyes that is circled to be white. I know we cant delete the eyes so i wanted to mask it, but i couldnt figure out a way. Below is my code. import cv2 import os cascPathface = os.path.dirname( cv2.__file__) +…
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Compute the optical density of a subimage in Matlab

I have a RGB image. I want to compute the Optical Density of a region of that image. I have converted the Image to grayscale and I know the formula for Optical Density is log(1/illumination). My procedure is to use roiploy to specify the ROI. But…
Sista
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Can I use ROI Pooling to extract region features from a feature map of the entire image in any task?

Is ROI pooling (e.g. in Pytorch) suitable for any tasks instead of object detection? For example, a pre-trained VGG16 on ImageNet. I use this image example as the input with the size of 640*640, and I will get a feature map with a size of 40*40…
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OpenCV circle ROI with transparent mask?

I'm trying to replace a detected face in an image with a modified one. I have no issue utilizing a regular rectangular roi. However, to be a bit more precise, I'm trying to use a circle ROI. I know you have to create a rectangular mask to do this.…
chris
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Opencv error: (-215:Assertion failed) (mtype == CV_8U || mtype == CV_8S) && _mask.sameSize(*psrc1) in function 'cv::binary_op'

I'm trying to paste a picture on the face detected through a haarcascade. While I was writing the code, I came across this error.. error: (-215:Assertion failed) (mtype == CV_8U || mtype == CV_8S) && _mask.sameSize(*psrc1) in function…
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How to Crop Stacks in ImageJ without first Duplicating

I am using imageJ for automated microscopy of live cells. The microscope centers the stage on a desired cell, takes a Z-stack, and passes this stack to imageJ. I want to then use Analyze Particles to output the area of the cell in each Z-slice.…
dlight
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Is Picture-in-Picture possible using OpenCV?

I would like to add a smaller image on top of a larger image (eventually for PiP on a video feed). I can do it by iterating through the relevant data property in the large image and add the pixels from the small image. But is there a simpler and…
Pedro Cunha
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How to design a label for visual recognition?

Sorry if this is a recurring question, but I can't find the right keywords for this search. I need to develop a system for visual recognition of labels attached to products from a warehouse. I'm using a fixed focus camera, so the idea is to use a…
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When using torchvision.ops.roi_align, I got the error:Process finished with exit code 139 (interrupted by signal 11: SIGSEGV)

My environment:torch-1.2, torchvision-0.3, python-3.7. I also tried other visions like torchvision-0.5, torchvision-0.6, but always got this error. What should I do could sovle this?
南琴歌
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Masking output of object detection (YOLO) on the corresponding images processed by the object segmentation model (U-net)

I used UNET to segment cracks on the road, and used YOLO to detect them. images were processed through the proposed YOLO and U-net models individually and the detected objects in the proposed yolo model image should be masked on the corresponding…
Max
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How to capture mouse movement for the whole window in opencv python?

I know and have seen tons of documentations explaining about how to capture mouse movement within a given window using mouseclick events in opencv. What I want to know is that if is there a way to capture mouse movements (x,y co-ordinates) for the…
Shivam Sahil
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