Crop video while Capturing

[seancassidy]

Hello Sirs,

For my project I am undertaking non-contact PPG acquistion. I am trying to capture my webcam but with the whole image I am getting a lot of noise in the signal. I have found using some example code provided by my supervisor in MATLAB that my webcam is capable of recording at 30fps.

I have integrated a video capture for processing in other programs. The VI currently records in a text file.

How would you suggest I crop the video frames before they are captured or processed, I need this for two reasons, 1. the whole image generates noise and 2. reduce the output file footprint.

 I have attached the VI for reference. To make it run a text file file path needs to be designated for the VI to run and a session for your WEBCAM.

Regards Sean 

P.S Vision Required.

[VintageWillis]

Hey,

i would have a look at this example:

https://decibel.ni.com/content/docs/DOC-11222

Hopefully that will help you

James

[seancassidy]

I'll give it a go.

[Gregory · Accepted solution]

If you open your camera in MAX, there may be properties for the width and height. You can create a property node on your camera session and use these names as the "active attribute" and then set the "value" with a string or numeric.

[seancassidy]

That is the best solution. What I have reverted to doing was to capture video, then crop it outside labview, then process it by each frame

[CarlosOtiniano]

 In this example, we will create a program in Labview to capture images from a USB camera to your application for further processing using the NI Vision module.

You can perform image acquisition only drivers from VAS , but for any treatment or handling or VDM VBAI you need , plus VAS . You can download the evaluation software from the following links :

Módulo NI Vision Development https://lumen.ni.com/nicif/us/evalvisiondevmodule/content.xhtml NI Vision Builder para Inspección Automatizada (AI) https://lumen.ni.com/nicif/us/machinevisionbrochure/content.xhtml NI Vision Acquisition Software http://joule.ni.com/nidu/cds/view/p/id/3818/lang/en

https://decibel.ni.com/content/docs/DOC-30531

7. RGB to 8_Bits.vi ‏50 KB

6. Webcam to RGB.vi ‏46 KB