A vision sensing system of a vehicle comprising a camera, an object detection module, and a calibration module. The object detection module is configured to detect a first object in data received from the camera. The calibration module is configured to calibrate the object detection module to detect the first object in the presence of a second object that obstructs a view of the camera and that includes a predetermined pattern sensed by the camera. A driver monitoring system for a vehicle comprises a camera and a driver monitoring module. The camera is arranged proximate to a steering wheel of the vehicle to monitor a face of a driver of the vehicle. The driver monitoring module is configured to detect an obstruction between the camera and the face of the driver and to ignore the obstruction in response to the obstruction including a predetermined pattern sensed by the camera.