I hope this face recognition software can help you it is called keylemon where it use your webcam to unlock your pc it can be downloader from cnet.
Please excuse me for bringing this up, but wouldn't it be better to get a fingerprint reader/scanner instead of a facial recognition lock? Security-wise I think it would work better because of unexpected changes to your facial structure and skin tone, if the program even goes that far for recognition purposes.
If it takes just the shape of your face for recognition then someone who looks similar can gain access, and if it does use colour and texture as well, something like getting a blue eye or a scar could impact your ability to gain access yourself.
I don't know much about the topic, but I think my points are valid depending on how you want to use it.