To connect this to your iMac, you'll need a USB cable and the "Ladybug" software from Lumens:
http://www.lumens.com.tw/support_1_1.php?p_id=13&big_id=1&pageNum_old=0
Scroll down to "
Ladibug MAC" for "MAC OS 10.4,MAC OS 10.5,MAC OS 10.7,MAC OS 10.8"
The manual for the Mac Ladibug software is here - I suggest you read it before installing the software
http://www.lumens.com.tw/a/program_download/file/201312301346105989.pdf
If it doesn't work - I can't really help. I don't own one and I don't know how well written the software is.
Good luck!