The number of college students taking courses online is surging, creating a tough dilemma for educators who want to prevent cheating.

Do you trust students to take an exam on their own computer from home or work, even though it may be easy to sneak a peek at the textbook? Or do you force them to trek to a proctored test center, detracting from the convenience that drew them to online classes in the first place?

The dilemma is one reason many online programs do little testing at all. But some new technology that places a camera inside students' homes may be the way of the future — as long as students don't find it too creepy.

This fall, Troy University in Alabama will begin rolling out the new camera technology for many of its approximately 11,000 online students, about a third of whom are at U.S. military installations around the world.

The device, made by Cambridge, Mass.-based Software Secure, is similar in many respects to other test-taking software. It locks down a computer while the test is being taken, preventing students from searching files or the Internet. The latest version also includes fingerprint authentication, to help ensure the person taking the test isn't a ringer.

But the new development is a small Web cam and microphone that is set up where a student takes the exam. The camera points into a reflective ball, which allows it to capture a full 360-degree image. (The first prototype was made with a Christmas ornament.)

When the exam begins, the device records audio and video. Software detects significant noises and motions and flags them in the recording. An instructor can go back and watch only the portions flagged by the software to see if anything untoward is going on — a student making a phone call, leaving the room — and if there is a sudden surge in performance afterward.

The inventors admit it's far from a perfect defense against a determined cheater. But a human test proctor isn't necessarily better. And the camera at least "ensures that those people that are taking classes at a distance are on a level playing field," said Douglas Winneg, Software Secure's president and CEO.

Troy graduate students will start using the device this fall, and undergraduates a year later. Software Secure says it has talked with other distance-learning providers, too. A potential future market is the standardized testing industry, which has struggled to find enough secure testing sites to accommodate growing worldwide demand for tests like the SAT college entrance exam and the GMAT for graduate school.

An estimated 3.2 million students were taking online classes in fall 2005, according to the most recent figures from the Sloan Consortium, a group of online learning providers that studies trends in the field, and that figure is almost certainly substantially higher today.

But many distance-learning providers do very little testing, including some of the largest, for-profit ones such as the University of Phoenix, Capella University and Walden University. Officials at all three schools said they rely mostly on student writing assignments.

Still, they need to be thinking about assessment. The military, whose tuition assistance programs are a huge source of revenue for online universities, is asking questions about testing to make sure students are earning credible degrees, Winneg said. Distance-learning programs also need to keep their accreditation agencies happy, as well as Congress, so that the programs can continue to receive federal financial aid dollars.

At Troy, like at many distance-learning programs, past testing options have been less than ideal. One was to line up a proctor from a list of acceptable exam monitors such as clergy or commanding officers.

"We just assumed and hoped the proctor would follow the instructions," said David White, director of the Southeast region for Troy. "In some cases they did, and probably in some cases they didn't."

The device will cost Troy students $125, White said.

Richard Garrett, a senior research analyst at Eduventures who follows online learning, said he finds the technology promising.

"The great unknown is, will it be seen as too invasive?" he said.