I think you can do that very easily in python: create a new python module in JeVois Inventor. Then in the process() function get your camera frame as OpenCV BGR numpy array. Then loop over the pixels, convert the BGR values to string representation, and issue a bunch of jevois.sendSerial(string). You should come up with your own strategy to delimit the frames, for example, send the whole frame as one very long string of BGR values converted to hex (2 bytes per B,G,R value), followed by a single \n at the end.
Just beware that the serial port is very slow compared to video frame rates...
Say 320x240 video resolution, times 3 for BGR, times 2 for encoding to ASCII hex = 460k bytes
at 115,200 bauds over the hardware serial port (i.e., about 10 kbytes/s) that will take about 45 seconds for 1 frame.