The Digital Window D7 camera, to be sold for $800, uses five sensors, like the ones in cellphones, to capture images in a 180-degree field of view.

STANDARD surveillance cameras guard homes, businesses and public spaces around the clock, but they do the job imperfectly: fish-eye lenses can distort the image, and pan-and-tilt cameras may point the wrong way at a crucial moment.

Now a new, six-ounce security camera the size of a deck of cards uses a different approach to cover a 180-degree field of view. It employs fixed, inexpensive sensors that divvy up the surveillance job, and smart software that instantly puts their separate views together into one live streaming video.