First-Photon Imaging: Scene Depth and Reflectance Acquisition from One Detected Photon per Pixel

Capturing depth and reflectance images using active illumination despite the detection of little light backscattered from the scene has wide-ranging applications in computer vision. Conventionally, even with single-photon detectors, a large number of detected photons is needed at each pixel location to mitigate Poisson noise. Here, using only the first detected photon at each pixel location, we capture both the 3D structure and reflectivity of the scene, demonstrating greater photon efficiency than previous work. Our computational imager combines physically accurate photoncounting statistics with exploitation of spatial correlations present in real-world scenes. We experimentally achieve millimeter-accurate, sub-pulse width depth resolution and 4-bit reflectivity contrast, simultaneously, using only the first photon detection per pixel, even in the presence of high background noise. Our technique enables rapid, low-power, and noise-tolerant active optical imaging.