Skip to main content

Stretch the dynamic range of the given 8-bit grayscale image using MATL...

Why webcams won't work with Image Acquisition tool when connected via USB hub?

 Hi,

 
I am currently doing a project that involves 3D reconstruction using a camera array.
 
I have 16 Microsoft HD-3000 webcams, Matlab R2017a on Windows 7 (64bit) OS.
 
I need the pictures to be taken simultaneously, which I found out is impossible with those webcams. Therefore I am recording short 'overlapping videos', measuring time difference between individual cameras triggering and ultimately extracting specific frames from the videos.
 
So far I have wrote a matlab code which detects how many cameras are plugged to the computer, then set camera parameters, records videos, saves them into the folder and measures time differences.
 
The code works fine when the cameras are plugged directly via computer's USB ports (tested on max. 8 cameras at a time since that is how many USB ports my computer has). However when I try plugging in the cameras via USB hub (StarTech), it won't work. It detects the cameras, sets parameters for each of them and 'tries' to take a video (it even gives me time difference), but the videos never appear on the drive. I am also getting following warning at the very beginning of running the code:
 
"Warning: An object in OBJ could not be started, was already started, or is invalid. "
 
All cameras are accessible and available for the preview in Image Acquisition Toolbox.
 
FYI, the USB Hub was supposed to be socket-powered, however it doesn't seem to work and I was testing it while powered from the computer.
 
Do you have any idea how to make it work? I have been struggling with this for the last couple of days.



NOTE:-

Matlabsolutions.com provide latest MatLab Homework Help,MatLab Assignment Help for students, engineers and researchers in Multiple Branches like ECE, EEE, CSE, Mechanical, Civil with 100% output.Matlab Code for B.E, B.Tech,M.E,M.Tech, Ph.D. Scholars with 100% privacy guaranteed. Get MATLAB projects with source code for your learning and research.

In my experience, it would not be uncommon for a computer with 8 USB ports to internally have 3 USB busses split over 2 USB controllers, with the second controller also handling the keyboard and mouse and Bluetooth.
 
 
For frame-level synchronization, ideally each camera should be on its own USB 3.0 bus. I would not consider putting more than 2 cameras on the same USB 2.0 bus (and would expect occasional glitches); I might generally be willing to test with 3 cameras on the same USB 3.0 bus but certainly not for real-time work -- and since those particular webcams only have USB 2.0 capacity, USB 3.0 ports would have to hold their speed down to USB 2.0 so with a USB 3.0 bus you would, in such a case, only get the benefit of a faster controller that might have more memory.
 
 
USB hubs are not really transparent to the USB process. You can examine your USB configuration and you will see each hub and you will see the ports attached to each of its ports.

Comments

Popular posts from this blog

https://journals.worldnomads.com/scholarships/story/70330/Worldwide/Dat-shares-his-photos-from-Bhutan https://www.blogger.com/comment.g?blogID=441349916452722960&postID=9118208214656837886&page=2&token=1554200958385 https://todaysinspiration.blogspot.com/2016/08/lp-have-look-at-this-this-is-from.html?showComment=1554201056566#c578424769512920148 https://behaviorpsych.blogspot.com/p/goal-bank.html?showComment=1554201200695 https://billlumaye.blogspot.com/2012/10/tagg-romney-drops-by-bill-show.html?showComment=1550657710334#c7928008051819098612 http://blog.phdays.com/2014/07/review-of-waf-bypass-tasks.html?showComment=1554201301305#c6351671948289526101 http://www.readyshelby.org/blog/gifts-of-preparedness/#comment_form http://www.hanabilkova.svet-stranek.cz/nakup/ http://www.23hq.com/shailendrasingh/photo/21681053 http://blogs.stlawu.edu/jbpcultureandmedia/2013/11/18/blog-entry-10-guns-as-free-speech/comment-page-1443/#comment-198345 https://journals.worldnomads.com

USING MACHINE LEARNING CLASSIFICATION ALGORITHMS FOR DETECTING SPAM AND NON-SPAM EMAILS

    ABSTRACT We know the increasing volume of unwanted volume of emails as spam. As per statistical analysis 40% of all messages are spam which about 15.4 billion email for every day and that cost web clients about $355 million every year. Spammers to use a few dubious techniques to defeat the filtering strategies like utilizing irregular sender addresses or potentially add irregular characters to the start or the finish of the message subject line. A particular calculation is at that point used to take in the order rules from these email messages. Machine learning has been contemplated and there are loads of calculations can be used in email filtering. To classify these mails as spam and non-spam mails implementation of machine learning algorithm  such as KNN, SVM, Bayesian classification  and ANN  to develop better filtering tool.   Contents ABSTRACT 2 1. INTRODUCTION 4 1.1 Objective : 5 2. Literature Review 5 2.1. Existing Machine learning technique. 6 2.2 Existing

Why are Fourier series important? Are there any real life applications of Fourier series?

A  Fourier series  is a way of representing a periodic function as a (possibly infinite) sum of sine and cosine functions. It is analogous to a Taylor series, which represents functions as possibly infinite sums of monomial terms. A sawtooth wave represented by a successively larger sum of trigonometric terms. For functions that are not periodic, the Fourier series is replaced by the Fourier transform. For functions of two variables that are periodic in both variables, the trigonometric basis in the Fourier series is replaced by the spherical harmonics. The Fourier series, as well as its generalizations, are essential throughout the physical sciences since the trigonometric functions are eigenfunctions of the Laplacian, which appears in many physical equations. Real-life applications: Signal Processing . It may be the best application of Fourier analysis. Approximation Theory . We use Fourier series to write a function as a trigonometric polynomial. Control Theory . The F