Stereoscopic Flash and No-Flash Photography for Shape and Albedo Recovery
Xu Cao,  Michael Waechter,  Boxin Shi,  Ye Gao,  Bo Zheng,  Yasuyuki Matsushita

We present a minimal imaging setup that harnesses both geometric and photometric approaches for shape and albedo recovery. We adopt a stereo camera and a flashlight to capture a stereo image pair and a flash/no-flash pair. From the stereo image pair, we recover a rough shape that captures low-frequency shape variation without high-frequency details. From the flash/no-flash pair, we derive an image formation model for Lambertian objects under natural lighting, based on which a fine normal map is obtained and fused with the rough shape. Further, we use the flash/no-flash pair for cast shadow detection and albedo canceling, making the shape recovery robust against shadows and albedo variation. We verify the effectiveness of our approach on both synthetic and real-world data.