Image capture with RPi camera

I would like to capture the image (preferably in grayscale) with MATLAB script, not from Command Window. (Unless it's the only way to capture the image ...) Then I would save it on RPi and compress it (still with MATLAB code) there. As far as I know snapshot command is working from Command Window and it automatically fetches the image to MATLAB. How can I capture and save the image directly on RPi (not sending it back to RPi from MATLAB)?

[Nipuna]

I used this approch

% Create a connection to the Raspberry Pi hardware

raspiObj = raspi;

system(raspiObj,'raspistill -o /home/pi/Pictures/"name.jpg"')