Image aquisition with high speed camera
21 次查看(过去 30 天)
显示 更早的评论
For my application, I want to use the image aquisition toolbox (with the NI Frame Grabber Support) to save images of fast moving objects taken by a high speed camera. These should be processed (recognition of object size and position using regionprops command)
The camara is recording with ~ 1000 fps, recording time min. 10 min.
The approaches I thought on:
Plan 1: Use shapshot function (https://de.mathworks.com/help/imaq/examples/acquiring-a-single-image-in-a-loop.html) in a loop, process image and only store required information (output from regionprops) in a cell.
Problem 1.1: Camera will be faster than loop and I need the high frame rate. Any ideas how to still get all informations?
Plan 2: Use imaqtool to create and save video, read in video later.
Problem 2.1: How to stop aquisition if video is "full"? (e.g: Maximal file size and size per frame- how do I get this? Or is there an automated possiblity?)
Problem 2.2: How can I set the framerate constant? (I need the object velocity so time interval between frames is important- when testing the image aquisition toolbox with my normal webcam, I had set the framerate to 30 but the shown framerate in the toolbox was 30 - 40. I need the framerate to be constant or at least the time stamp for each frame to calculate the error)
Thanks for your help! :)
0 个评论
采纳的回答
Walter Roberson
2019-5-21
The approaches you describe cannot work.
You need a hardware trigger for constant frame rate. However if you were using an ni CompaqDaq chassis you might be able to use software control to tell the chassis what trigger rate to set.
You need a big frame buffer attached to the frame grabber.
In theory you could use a standalone device with SSD and hardware trigger to record everything for later transfer.
I would not even try to do this without using an interface that was one of USB 3, or Thunderbolt 3, or Gigabit Ethernet, or pci express (in which case you should consider Thunderbolt 3)
Perhaps it might be feasible with a GigE camera; I would have to know more about the image sizes (and do a bunch of research)
Any attempt to use software triggers such as snapshot will have too much jitter, too much latency.
(At 1000 fps I wonder whether you are going to have sufficient brightness for imaging.)
4 个评论
Walter Roberson
2019-5-22
National Instruments does not appear to make any frame grabbers that work with that device, as it uses Coaxpress interface.
更多回答(0 个)
另请参阅
类别
Test and Measurement
Image Acquisition Toolbox
Image Acquisition Toolbox Supported Hardware
GigE Vision Hardware
Image Processing and Computer Vision
Image Acquisition Toolbox
Image Acquisition Toolbox Supported Hardware
GigE Vision Hardware
Test and Measurement
Image Acquisition Toolbox
Image Acquisition Toolbox Supported Hardware
National Instruments Frame Grabbers
显示更多
在 Help Center 和 File Exchange 中查找有关 GigE Vision Hardware 的更多信息
产品
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!