Using their software I can make the appropriate settings in both of the cameras. When closing the software, and restart python and running the script, the captured images appear exactly according to the settings that I have set in the Logitech Webcam Software. Learn more. Asked 3 years, 3 months ago. Active 3 years, 3 months ago. Viewed 7k times. VideoCapture cap1. Can you elaborate more on that? Do you mean that when I call cv2.
It is possible that your camera is not entirely supported by OpenCV, not all features of all cameras are enabled in OpenCV. You may set some of this things, but not all. How do I make a patch in order to make it supported? Can you detail the procedure of patch making?
Sorry but I am really a new user of both Python and Opencv. Active Oldest Votes. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.
Try to use VideoCapture 0, cv. I've tried this sample with modified constructor and cap. I've found that focus values should have range even maybe ? Forgot to mention, I was using virtual box to run on windows. If I run the same code on windows machine directly everything works Must be some problem with virtual box. Though there are two black bars on sides and actual image has aspect ratio.
Looks like all resolutions have black bars e. Asked: Video Playback via Microsoft Media Foundation msmf. First time here? Check out the FAQ! Hi there! Please sign in help. How to disable autofocus of a webcam on Windows 10? Closed for the following reason the question is answered, right answer was accepted by ZubenkoMikhail close date Are you able to get 4k resolution on Windows?
At what fps? Can you change the FOV angle? I've been able to get x and x at 30 FPS.
Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub?
Sign in to your account. We use optional third-party analytics cookies to understand how you use GitHub. Learn more. You can always update your selection by clicking Cookie Preferences at the bottom of the page.
For more information, see our Privacy Statement. We use essential cookies to perform essential website functions, e.
We use analytics cookies to understand how you use our websites so we can make them better, e. Skip to content. Dismiss Join GitHub today GitHub is home to over 50 million developers working together to host and review code, manage projects, and build software together.
Sign up. New issue.
Jump to bottom. Conversation 3 Commits 8 Checks 0 Files changed. Copy link Quote reply. Contributor Author. This also fixes passing boolean values. Hide details View details opencv-pushbot merged commit b into opencv : master Oct 23, 1 check passed. Merge pull request from paroj:v4l2ctrls.
Python samples adapted for Python3 compatibility …. Python samples adapted for Python3 compatibility Sign up for free to join this conversation on GitHub.
Already have an account? Sign in to comment. Linked issues. Add this suggestion to a batch that can be applied as a single commit. This suggestion is invalid because no changes were made to the code.Recently, one of my colleagues mentioned to me that he takes large numbers of pictures and wanted to write a program to automatically determine which was in the best focus, out of a group of pictures that were taken of the same scene. He mentioned that he expected the algorithm to be computationally intensive.
So I checked out the Wikipedia article on autofocus. Two general algorithms are described, active autofocus and passive autofocus. Within the category of passive autofocus algorithms, Wikipedia describes two methods, phase detection and contrast measurement. Again, since my images have already been captured, I will use contrast measurement. So what does an autofocus system using contrast measurement consist of?
I imagine a lens system, a sensor and a processor that reads the sensor, which can then adjust either the positions of the optics in the lens system or the position of the sensor relative to the lens system.
Subscribe to RSS
When the user wants to take a picture, the processor will read the sensor, make a contrast measurement and repeat this process, sweeping the variable position part of the system through its range. Then it will select the position that gave the best contrast measurement. Thinking about this, I imagine a picture with many black-and-white stripes — if the stripes are in perfect focus, there will be many large transitions in brightness high contrastand if the stripes are blurred, then we would expect the transitions in brightness to be less dramatic.
So how to measure the contrast in a picture in a way that works quickly on a tiny low-power processor? The simplest method that came to mind was to sum the differences in pixel values across the image.
This is a nice O N algorithm. So if we inserted the autofocus algorithm after this conversion in our low-powered camera, we could run it on just the luma plane. In addition to being less computationally intensive, that might be more accurate because the human eye has different sensitivities to different wavelengths of light, and using the luminance values would come closer to what we really want. In this case, I want to concentrate on contrast detection and not the mechanics of reading and decoding JPEG files.
As you can see, Octave let me express this algorithm very concisely. First, I read in the image into the variable img. I then iterate over the image, and each time i contains a vector of pixel values.
Octave iteration and subscripting is a bit mysterious to me, and I always have to read the manual, but this is what it does in this case. It turns out that each of these vectors is a column vector of the image. Then, for each of these column vectors, I accumulate the sum of the absolute value of the first differences in pixel values. At the very end, I print out the value accumulated over the whole image. I should be able to use this program to evaluate the focus of two images, where the one with the larger result at the end should be more in focus because it has higher contrast.
My first attempt at this program left out the uint64and I got results of for the first images I tried. It turns out that Octave is doing saturation arithmetic, and so I need to cast the values to a wider integer. If we computed a combined brightness value for each pixel, we could use a bit accumulator instead.
The horizontal stripe image works as one would expect, the in-focus image generating a higher metric than the blurred one.
My camera must be looking at contrast across rows, so it has the same behavior of my Octave code, albeit in a different direction. This is further confirmation that my digital camera actually uses something very similar to this algorithm to autofocus. As we expect, the unblurred image gives a higher contrast measurement, so the algorithm is detecting that it is more in focus. This would involve just running the algorithm over a subset of the image, such as the center of the frame.
Many cameras also offer the option of automatically detecting human faces and autofocusing there.GitHub is home to over 50 million developers working together to host and review code, manage projects, and build software together. Work fast with our official CLI. Learn more. If nothing happens, download GitHub Desktop and try again. If nothing happens, download Xcode and try again. If nothing happens, download the GitHub extension for Visual Studio and try again.
We use optional third-party analytics cookies to understand how you use GitHub. You can always update your selection by clicking Cookie Preferences at the bottom of the page. For more information, see our Privacy Statement. We use essential cookies to perform essential website functions, e. We use analytics cookies to understand how you use our websites so we can make them better, e.
Skip to content. Autofocus using opencv and python 1 star 0 forks. Dismiss Join GitHub today GitHub is home to over 50 million developers working together to host and review code, manage projects, and build software together. Sign up. Go back. Launching Xcode If nothing happens, download Xcode and try again.
Latest commit. Git stats 22 commits. Failed to load latest commit information. Haar Transform's. View code. About Autofocus using opencv and python. Releases No releases published. Packages 0 No packages published. Contributors 2. You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window.
How can i set from openCV the focus of a webcam or any other camera? I would like to find the distance of on object, but I want to write the program, so I need to manually be able to focus, manually meaning from code. You can't set focus from opencv, but windows SDK allows it. I'm using Logitech webcams tested C, C and Ce.
The key 28 is for setting focus. Note that the focus value should be multiples of 5 0, 5, Learn more. Manually focus webcam from openCV Ask Question. Asked 6 years, 11 months ago. Active 3 years, 7 months ago. Viewed 10k times.Autofocus Test - Panasonic Lumix S5
Apahidean Iancu Apahidean Iancu 1 1 silver badge 6 6 bronze badges. Active Oldest Votes. All Rights Reserved. Andrey Smorodov Andrey Smorodov 9, 2 2 gold badges 28 28 silver badges 36 36 bronze badges. It is better to use cv2. Makes it much more cleaner and readable. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Ben answers his first question on Stack Overflow.
Detecting Well-Focused Images
The Overflow Bugs vs. Featured on Meta. Responding to the Lavender Letter and commitments moving forward. Linked 0. Related Hi, I'm using some very simple web cam, during the chessboard calibration I got every time very different intrinsic matrix especially the part with focal lengthsis it because the camera has auto-focus?
If I take the pictures of multiple chessboard position the undistorted image is afterward more distorted then the originalhow can it be? Is it possible the auto-focus is disturb somehow the distortion parameters calculation? When I want to calculate projection matrix I need non-variable focus lengthneedn't I? But I don't understand how such a camera can have auto-focus, when the there is need to screw the lens to make the picture sharp?
I thought auto-focus is moving some lens to focus?? And second question is if I want to make a laser scanner. I need to somehow calculate the homography to laser plane is it right? So probably I can directly find the laser line on the chessboard during the calibration. But do I need to measure the distance of the chessboard or can I somehow calculate the distance from the chessboard?
Subscribe to RSS
Do I need chessboard 3D coordinates to calculate the extrinsic matrix? To determine intrinsic parameters, you need to capture many images of the same chessboard, in different positions. If the auto focus seems to be a problem, try to put your chessboard always in the same distance from the camera. To evaluate the extrinsic parameters, you need the 3D coordinates of chessboard. For the laser line, you can evaluate the coordinates of the line with the extrinsic parameters, with the chessboard, but what is your purpose?
If you move the camera, the 3D coordinate extrinsic parameters will changed.
Could you please describe your setup with the laser? Where the objects will be, is the camera moving, is the laser line moving? Thanks for quick answer. I thought it is important the chessboard position will vary.
I understand you want to neglect the influence of auto-focus, will try anyway. Is it correct the intrinsic matrix should be always nearly the same for the same camera setup? It will be line laser shining on the scene, this line creates the laser plane, so my idea that there will be some matrix chain that will give me for specific 2D point of laser line in picture it's 3D coordinate on the laser plane.
Just now I only want to convert the laser line to 3D point. I need to confess I'm little bit lost in here:. I wanted to start with moving object, but afterward the camera with the beam will move.