Aqua reversing camera

I have a 2013 Prius Aqua. U=It was an import from Japan to New Zealand so the on screen instructions and buttons are all in Japanese, which I do not read. The reversing camera is no longer working and I cannot find any way to turn it back on. I will appreciate any help.

 

Thanks 9001, I'll give that a try. My grandson said that he already tried that and still couldn't figure it out, but I will give it a try too. Will post whatever I find here to help others who find this problem. Cheers, R