1. A system for monitoring objects in athletic playing spaces, comprising: a camera positioned to capture images of an object in an athletic playing space, wherein the camera is configured to provide image data defining frames of the captured images, and wherein the image data is in a format relative to a first coordinate system; a depth sensor positioned to sense depths for objects in the athletic playing space, wherein for one of the frames the depth sensor is configured to provide a depth map having a plurality of depth pixels corresponding with a plurality of Image pixels of the one frame, and wherein each of the depth pixels indicates a sensed depth for at least one corresponding image pixel of the one frame; and at least one processor configured to identify a playing surface plane defined by the depth pixels and to determine a direction of gravity in the one frame based on the identified playing surface plane, the at least one processor further configured to calculate at least one performance parameter based on the image data and the determined direction of gravity, wherein the playing surface plane corresponds to a playing surface of the athletic playing space in which athletes participate during a sporting event.