Alphabet Inc.'s GOOGL 0.86% Nest Labs in September announced a doorbell equipped with a Qualcomm Inc. QCOM 0.27% chip, a video camera and facial-recognition software that can send an alert to a Nest mobile app if it sees a familiar face. The market for computer-vision systems is nascent, poised to expand from roughly $1 billion last year to $2.6 billion in 2021, according to International Data Corp. Emerging products such as autonomous vehicles and personal robots portend continuing growth, and Intel Corp. INTC 0.25%, Qualcomm and other chip makers are jockeying to supply the brains to new machines. "These [applications] are edging into viability," said IDC analyst Michael Palma. "Maybe not mass viability, but very, very close."