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Questions tagged [computer-vision]

Use this tag for questions related to Computer Vision -- any aspect of software that enables computers to perceive, understand and react to their environment using cameras. For questions related to image filtering and quantification, use the tag [image-processing] instead.

Computer vision enables images, or sequences of images, to be processed by a computer using algorithms. There are many aspects to computer vision, including mathematics, physics (especially optics), imaging hardware, , and .

Some basic techniques used in computer vision are:

  • Image acquisition
  • Pre-processing
  • Feature Extraction
  • Detection/Segmentation
  • High-Level processing
  • Decision making
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Image comparison - fast algorithm

I'm looking to create a base table of images and then compare any new images against that to determine if the new image is an exact (or close) duplicate of the base. For example: if you want to reduce storage of the same image 100's of times, you…
meade
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Simple Digit Recognition OCR in OpenCV-Python

I am trying to implement a "Digit Recognition OCR" in OpenCV-Python (cv2). It is just for learning purposes. I would like to learn both KNearest and SVM features in OpenCV. I have 100 samples (i.e. images) of each digit. I would like to train with…
Abid Rahman K
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How to detect a Christmas Tree?

Which image processing techniques could be used to implement an application that detects the Christmas trees displayed in the following images? I'm searching for solutions that are going to work on all these images. Therefore, approaches that…
karlphillip
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Simple and fast method to compare images for similarity

I need a simple and fast way to compare two images for similarity. I.e. I want to get a high value if they contain exactly the same thing but may have some slightly different background and may be moved / resized by a few pixel. (More concrete, if…
Albert
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How to remove convexity defects in a Sudoku square?

I was doing a fun project: Solving a Sudoku from an input image using OpenCV (as in Google goggles etc). And I have completed the task, but at the end I found a little problem for which I came here. I did the programming using Python API of OpenCV…
Abid Rahman K
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OpenCV C++/Obj-C: Detecting a sheet of paper / Square Detection

I successfully implemented the OpenCV square-detection example in my test application, but now need to filter the output, because it's quite messy - or is my code wrong? I'm interested in the four corner points of the paper for skew reduction (like…
dom
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How to verify CuDNN installation?

I have searched many places but ALL I get is HOW to install it, not how to verify that it is installed. I can verify my NVIDIA driver is installed, and that CUDA is installed, but I don't know how to verify CuDNN is installed. Help will be much…
alfredox
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Face recognition Library

I'm looking for a free face recognition library for a university project. I'm not looking for face detection. I'm looking for actual recognition. That means finding images that contain specified faces or libraries that calculate distances between…
Janusz
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How to train an artificial neural network to play Diablo 2 using visual input?

I'm currently trying to get an ANN to play a video game and and I was hoping to get some help from the wonderful community here. I've settled on Diablo 2. Game play is thus in real-time and from an isometric viewpoint, with the player controlling a…
zergylord
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Converting RGB to grayscale/intensity

When converting from RGB to grayscale, it is said that specific weights to channels R, G, and B ought to be applied. These weights are: 0.2989, 0.5870, 0.1140. It is said that the reason for this is different human perception/sensibility towards…
ypnos
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How can I extract a good quality JPEG image from a video file with ffmpeg?

Currently I am using this command to extract the images: ffmpeg -i input.mp4 output_%03d.jpeg But how can I improve the JPEG image quality?
Daniel Gartmann
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What is "semantic segmentation" compared to "segmentation" and "scene labeling"?

Is semantic segmentation just a Pleonasm or is there a difference between "semantic segmentation" and "segmentation"? Is there a difference to "scene labeling" or "scene parsing"? What is the difference between pixel-level and pixelwise…
Martin Thoma
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What is the mAP metric and how is it calculated?

In computer vision and object detection, the common evaluation method is mAP. What is it and how is it calculated?
cerebrou
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How do I choose between Tesseract and OpenCV?

I recently came across Tesseract and OpenCV. It looks like Tesseract is a full-fledged OCR engine and OpenCV can be used as a framework to create an OCR application/service. I tried using Tesseract on some of my images and its accuracy seems…
Legend
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How to draw a rectangle around a region of interest in python

I'm having trouble with import cv in my python code. My issue is I need to draw a rectangle around regions of interest in an image. How can this be done in python? I'm doing object detection and would like to draw a rectangle around the objects I…
user961627
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