Had the same problem and solved it - The Matlab didn't recognize my camera - pointgrey Blackfly S Monochromatic cased camera BFS-U3-200S6M-C with USB3 connector. After many tries it worked, propably because I didn't downloaded the full SDK. I installed with 'winvideo' adaptor (might work with 'pointgrey').
1. Check installed 'winvideo' (in Matlab command window - '>>imaqhwinfo' ) and image acquisition toolbox for pointgrey hardware (or any other imaqtoolbox required).
2. download the full SDK from:https://www.ptgrey.com/Downloads. I specifically downloaded for my camera from https://www.ptgrey.com/Downloads/GetSecureDownloadItem/11099
Make sure to install the directShow in the installation progress of the SDK developer, and that the download is of full SDK.
3. Manually register the DLL, run as administrator: Start Menu>All Programs>Point Grey Spinnaker SDK (64bit)>DirectShow_vs201X>Register DirectShow Dlls