Using one or more patterned markers inside the projector module of a three-dimensional (3D) camera to facilitate automatic calibration of the camera's depth sensing operation. The 3D camera utilizes epipolar geometry-based imaging in conjunction with laser beam point-scans in a triangulation-based approach to depth measurements. A light-sensing element and one or more reflective markers inside the projector module facilitate periodic self-calibration of camera's depth sensing operation. To calibrate the camera, the markers are point-scanned using the laser beam and the reflected light is sensed using the light-sensing element. Based on the output of the light-sensing element, the laser's turn-on delay is adjusted to perfectly align a laser light spot with the corresponding reflective marker. Using reflective markers, the exact direction and speed of the scanning beam over time can be determined as well. The marker-based automatic calibration can periodically run in the background without interfering with the normal camera operation.