Simple range cameras based on focal error

We describe research on two imaging range sensors that use defocus to estimate range. One technique is completely passive and provides dense range measurements in textured areas with an rms error of 2.5%. This method can be useful when stereo is unreliable because of correspondence errors or when imaging geometry prevents the use of multiple viewpoints (e.g., microscopy). The second technique uses structured light and provides dense range measurements with an rms error of 0.5%. This method can be useful when imaging geometry prevents the use of multiple viewpoints and for acquiring range imagery of rapidly moving objects, as the structured light can be delivered in a single stroboscopic flash.