I took out of an old security camera its circuitry and I am trying to figure out a way to connect it via USB to my computer and use it as a standard webcam. Is it possible? Here are the front and the back of the camera circuit. There are the 12V, GND and Video pins. But also there are the 3.3v, SDA, SCL and GND pins which are unused. Maybe those pins can be used to extract image data from the CMOS, but I'm not entirely sure about that. But maybe, is it possible to just take the analog VIDEO pin and convert it to digital data and use the stream as a webcam? Thanks.
If there is an analogue output, your best bet is to buy an adapter to connect the camera to the computer. I guess that the signal on the 3x1 connector is standard.
The I2C bus, most probably, is there to program the board microcontroller. Depending on the frame rate and resolution of your video feed, I2C data rate would range from barely adequate to completely inadequate. Even if there was some kind of digital feed there, that won't be standard, therefore you would have to reverse engineer that.
On top of everything, a cheap webcam probably costs less than the converter, has built in power supply, and has lenses. In case you did not know, lenses are necessary for the sensor to work properly, so if you have the original enclosure make sure to test inside it, otherwise you won't be getting anything useful from that.
All in all, if it's not for fun and to learn, just buy a webcam.