There is a big difference between the kinds of cameras that most people on this forum work with (industrial video cameras) vs consumer or prosumer point-and-shoot cameras. The point-and-shoot camera (PS) is generally designed to take snapshots. Ease-of-use, feature set, image quality, and image size are the dominant factors affecting consumers' choices. The industrial camera is designed with the following attributes as a priority: Speed, light sensitivity, speed, ruggedness, speed, and the ability to use a number of different kinds of lenses. Oh, did I mention speed? Many machine vision applications require the processing of many images per second - something that simply cannot be done using a PS camera.
Certainly, the distinction between the two types is getting blurred (no pun intended) as PS cameras are advancing in their feature set. For example, some DSLR's also provide real-time imaging capability (e.g. movies). In a few years there may be little difference between the two types of cameras but for now there is a large difference.
Regaring interfacing to PC's: You are correct in stating that many PS cameras provide a USB connection. This is generally used for file transfer and not camera control. Some camera manufacturers provide additional functionality via the USB port through their software development kit (SDK). The SDK communicates with the software inside the camera (firmware) to provide additional capability such as shutter control, zoom, image size, etc. I know that Olympus provides an SDK for some of their cameras. I think Canon does as well. Not sure about Nikon or others. Bottom line - you have to write your own software using Visual Basic or C++ to control the camera or purchase thrid-party software to do it. Also, some PS cameras provide a somewhat crude though functional interface called TWAIN which can be used to remotely control the camera. The TWAIN interface can be somewhat restrictive depending on how it is implemented by the various camera manufacturers.
Regarding interfacing to industrial cameras: Back in the olden days when all electronic cameras were of the analog (TV) variety, a frame grabber was required to convert the analog signal into something useable by the PC. These products are still available, but generally most applications use digital interfaces. The common ones are FireWire (IEEE-1394a) or USB. There are some higher-end ones that require special hardware such as CameraLink and Gig-E.
Hope this helps.
BTW - What is your application? Maybe I or others can recommend a solution for you.
Message Edited by Steverino on 04-13-2010 02:21 PM
Message Edited by Steverino on 04-13-2010 02:24 PM
