Questions tagged [opencv]
OpenCV (Open Source Computer Vision) is a cross-platform library of programming functions for real time computer vision.
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Salt and Pepper impulse Denoising opencv
I am creating a generic method to work on salt and pepper noise and variants. The example images are as shown below :
I tried few methods, such as
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Finding defects in wall paint (finding difference in textures)
I have been experimenting with computer vision techniques to find defects in paintings, more specifically defective brush strokes. I have tried a handful of techniques such as different filters, One ...
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Finding point height on a cup using OpenCV
Suppose that I want to find the 3D position of a cup with its rotation, with image input like this (this cup can be rotated to point in any direction):
Given that I have a bunch of 2D points ...
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How to find position, scale and rotation of a known shape/contour in an image?
I have an image of an object.
The image shows a high contrast outline of the object.
It is guaranteed that the image shows exactly one object.
The shape/contour of that outline is known.
It is not ...
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Licence plate enhancement
Is it possible to enhance the image below and make it more readable?
I have tried apply binarization but there is some kind of shadow.
So I have tried to convert image to gray scale and then ...
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How to find location of minimum dimension of contour using opencv?
suppose this is our input image and now we have to detect the point of minimum dimension, which I show as the red dot in an output image
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Running the BM3D Denoising Algorithm in Python
I am looking for a strong baseline in image denoising and therefore wanted to have the BM3D algorithm in my benchmark.
These 2 python implementations:
https://github.com/ericmjonas/pybm3d
https://...
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1
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Looking for a way to fill holes in objects, and break bridges between them
I am trying to extract building footprints from satellite images. Using a series of morphological operations i.e erosion and opening by reconstruction, I'm able to obtain the footprints, albeit with a ...
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SIFT between 1 image and dataset (2 images)
I use SIFT, and I want to find the angle of inclination of an image compared to two reference images, in short:
I have 3 images :
Image x: input image
Two images 1 and 2, reference images that are ...
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1
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How to produce color image using edge detected images?
Hi I am trying to produce an image which is a combination of multiple images such as in focus stacking. Now I have 6 photos and I want to produce a final image such that the final image uses blocks of ...
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Detect valve position without colors
I can't find a solution for my problem and I need your help.
I have to create an application to detect if a valve is open or close like this :
https://www.youtube.com/watch?v=VY92fqmSdfA
Some ...
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Face image quality assessment
I'm trying to filter out bad face images (with artifacts) generated by StyleGAN.
Is there a good image quality measurement mechanism in python for doing this?
I've tried using BRISQUE but it is not ...
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How do I filter out this horizon from my contour?
I am trying to identify the T-rex and obstacles (cactus and bird) from Google's no-internet game.
What I have done is:
Apply GaussianBlur filter
Apply Canny
Apply Dilate
Apply erode
findContours ...
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3
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Recommended Order of Performing Denoising, Deblurring and Super Resolution on an Image
In the normal workflow of image processing, there are multiple operations, increase image contrast, image denoising, image deblur and image super-resolution. What are the sequence/order of performing ...
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Finding Homography Matrix Using Lines
I have some Points and Lines from original image and the corresponding points and lines from top view image.
-> I tried to find homography using points
Used OpenCV function findHomography(...
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1
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Gender classification using Periocular Region [closed]
I have a dataset of the periocular region, I have images of the male and female periocular region but they are only labeled as left and right periocular region, Folder is a mixture of male and female ...
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Size filtering on binary images
I have noisy images from which I extract the contours using OpencCV's findCountours, which performs binarization internally. This results in innumerable small ...
user7657
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2
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Camera image pixel structure origin
I am using machine vision for industry task with opencv. I have images from a camera monitoring the process. The detailed look at the small part of the image follows:
Enlarged:
In the detail, it ...
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How do I detect the sharp edges in the following image?
I am looking to count the sharp pointy triangular things in the image. However I was unable to do so. One approach I did try was take a convex hull of the contour and then find convex defects but it ...
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Outlined text extraction from image using OpenCV
I have some video frames I'd like to extract some text from (for making softsubs from hardsubbed video for learning). The text in question is mostly in Chinese script (some numbers and Latin letters) ...
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2
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What impact have different types of border-handling on high pass or low pass filtering?
When high or low pass filters are being applied to an (grayscale) image, the borders need to be handled separately. They could be filled with 0's or 255's (b/w), repeat the nearest pixel value, or ...
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How can I calculate homography from the room height and camera calibration matrix?
EDIT2: I've added an assumption that the camera calibration matrix is given. Other factors (rotation, camera pose) are still not given.
I want to measure actual lengths of floor edges (blue lines in ...
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1
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4k
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OpenCV warpPerspective implementation
I've implemented the least squares method to find the homomorphic image to fix the rotation and projection in an image.
Now I'm trying to implement the OpenCV warpPerspective method in order to "fix" ...
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0
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KLT tracker, reject tracked occluded points
I want to use KLT tracker for a visual odometry application. Thus, I only want to track object features. Currently I'm using OpenCV's implementation ...
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0
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Implementing Edge Preserving Diffusion (Anisotropic Diffusion)
I am trying to implement edge preserving diffusion. Recall the general diffusion equation to be:
$$\DeclareMathOperator{\Div}{div}\delta_t u = \Div(g \nabla u)$$
Where $g$ is the speed of the ...
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Sum of Squared Intensity Difference for block matching with ORB features, c++
I am trying to implement feature matching algorithm between image reference and image current.
The pipeline is as follows:
...
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1
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What principles to use, in order to create field that will be read by OCR?
I currently have an invoice, where some numbers are written by hand, and I would need to read them automatically.
My past experience is that people who write numbers will them write in so many ...
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3k
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python: how to compute the sharpness features of image
I am extracting the sharpness features of image as shown in the following image mentioned in a paper.
I have done with the following code.
Firstly, use the open cv convert the RGB to HSL (luminance ...
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1
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python: how to compute the gray level histogram features as mentioned in the paper, and
Hi I am extracting the grey level features of image mentioned in this paper (part 4.5 low level features).
"We describe two low level features that are particu- larly important for photo quality ...
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1
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How can I detect pipeline cracks using OpenCV and Python?
I have developed a robot that captures images of the pipeline interior as it moves. The requirement was to be able to detect cracks inside. So far i tried several OpenCV codes that find the crack ...
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Segmenting an image into columns
I want to segment the image below (click for bigger image) into columns based on the natural gaps that exist in the columns. The columns should be perfectly vertical and need not be the same size, but ...
user38841
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How to segment multiple overlapping coins (ellipses)
I am doing a program that counts coins (and tells their value by their size) with OpenCV (C++).
Let's say we have an image of some coins.
If there is an overlap of two coins at the same time, it is ...
Cacahuete Frito
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Is it possible to generate depth map from graycode sequence without using printed calibration patterns?
In a camera-projector system, if only the camera's intrinsics are known, is it possible to generate the depthmap fully automatically through a graycode sequence without any manual calibration process (...
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Image processing based on wavelet transform in python [closed]
I take the dwt2 for an image and saved it's coefficients (LL,Lh, hl,hh) using pywt.dwt2 (image,'haar'),in my project I have to change them to uint8 but when I change their types and reconstruct the ...
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Signal in frequency domain with OpenCV dft
I am experimenting with cv::dft: a 1HZ sinus signal is generated, and displayed in the frequency domain. But for some reason it hasn't got the maximum component at ...
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Removing noisy lines from image - opencv - python
I want to process different type of image to extract actual text from noisy image .I am using open cv to do this job it is working fine but the problem is I need to set different lower threshold to ...
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What does opencv `mean` function do when passing a mask of zeros?
INTRO
I am looking at this project to implement some changes.
The project is written in C++ using openCV library. Its goal is to detect cars in parking area to calculate the number of free spots. It ...
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Scale and Rotation invariant color based feature descriptors
SIFT/SURF/ORB etc are grayscale based, if the two grayscale bitmap is very similar, but the RGB channel is quite different, how to classify them? So, I think there should be some color based feature ...
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How to Find the Probability of Kalman Filter States?
I am working on a video object tracking problem. I am using Kalman filter to predict and correct the object position return by an algorithm such as CamShift. I want to adjust the likelihood ...
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blur detection using opencv
I'm writing a script to detect blur images using OpenCV by applying Laplacian filter and calculate the std but there is a problem the std for images that contain motion blur is very close to those ...
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Is the behaviour of the following filter plausible?
I've designed a filter based on this equation
$$
E(u) = \frac{1}{2}\int_{\Omega} \left[(u-f)^2 + g(\lVert \nabla u \rVert)\right]dxdy
$$
Euler-Lagrange equations in this case are (should be) given ...
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997
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Automatically detect an image collage
I'm trying to automatically detect if an image is a collage vs a single photograph. I'm not too concerned with difficult cases of artistic collages. What I'm trying to solve is rectangular collages ...
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API/ Library for re-orienting 360 degree camera frame efficiently
I am trying to correct the orientation of a 360 degree camera frame using roll, pitch and yaw estimates coming from my C++ Extended Kalman Filter (EKF) code. I am interested in using libraries and ...
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opencv otsu binarization not working
I tried to apply opencv OTSU binarization on the following image, but it generate a black image.
Here is the following python code:
...
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1
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657
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Wiener deconvolution in cpp giving back the same image
I was trying to deblur a noisy image using wiener deconvolution.
I found this code which added noise to an image and removed it as well.
Modifying this code only i tried to implement the exact formula ...
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Gaussian Equivalent of Convolving an Image 50 Times with a Box Filter
I have a image that I'm convolving 50 times with a box filter, and I like to replace this with a single gaussian filter. Because both box filter and gaussian filter are separable I can just study the ...
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How to detach overlapping contours but not to remove small ones. Alternative to erosion-dilation cycle
Background:
I'm trying to detect trees on a sequence of aerial images by calculating a stereo disparity for consequent pairs of images. This is how disparity looks like. White spots are trees:
Next, ...
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How to recognize speech bubbles in comic strips (Ideally OpenCV)
I need to recognize speech bubbles to send to OCR and also to know where they are in the strip.
How could I do this with OpenCV?
I'm using OpenCV 2 and Python 3.6
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Techniques for recognizing white rectangular labels in these pictures? (Ideally OpenCV)
I need to recognize these two types of labels.
zBar does recognize some of the barcodes sometimes, but I'd need to catch the ones that it doesn't and detect the label, so I can try and straighten up ...
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Skewed rectified aerial images
I have a series of aerial images from which I would like to get disparity maps for every consequent pair. In order to do that I do a stereo rectification.
The problem is that sometimes rectified ...
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