Microsoft Patent | Systems and Methods of Active Brightness Depth Calculation for Object Tracking

Patent: Systems and Methods of Active Brightness Depth Calculation for Object Tracking

Publication Number: 20180373348

Publication Date: 2018-12-27

Applicants: Microsoft

Abstract

A method of object tracking in a head-mounted display includes illuminating a field of view with an infrared illumination source, capturing an infrared illuminated frame of the field of view with an infrared camera, detecting a tracking object in the field of view, calculating an x-position and a y-position of the tracking object in the field of view, measuring a maximum brightness of the tracking object, and calculating a position of the tracking object using the maximum brightness.

Background

Virtual reality (VR) and mixed reality (MR) display systems allow a user to experience visual simulations presented from a computer. Some visual simulations are interactive and allow the user to interact with the simulated environment. A user can interact with the simulated environment by spatial and orientation tracking of the display system and peripheral controllers, such as handheld devices.

Spatial and orientation tracking of peripheral controllers can include a variety of tracking methods. Conventional tracking includes incorporation of inertial measurement unit (IMU) or gyroscopic sensors, magnetic field-based tracking, acoustic tracking based on microphone array, camera-based tracking with a light-emitting diode array, or depth cameras (structured light and/or time-of-flight). Conventional low-cost options compromise precision, while higher-precision options have increased resources associated with their power or cost.

Summary

In some embodiments, an object tracking system includes an infrared illumination source mounted to a head mounted display; an infrared sensitive camera mounted to the head mounted display; and a handheld electronic device. The handheld electronic device includes a tracking object with a known reflectivity in the infrared range.

In other embodiments, a method of object tracking in a head-mounted display includes illuminating a field of view with an infrared illumination source, capturing an infrared illuminated frame of the field of view with an infrared camera, detecting a tracking object in the field of view, calculating an x-position and a y-position of the tracking object in the field of view, measuring a maximum brightness of the tracking object, and calculating a position of the tracking object using the maximum brightness.

In yet other embodiments, a method of object tracking in a head-mounted display includes illuminating a field of view with an infrared illumination source mounted to the head-mounted display, capturing an infrared illuminated frame of the field of view with an infrared camera mounted to the head-mounted display, detecting a first tracking object on a handheld device in the field of view, calculating a first x-position and a first y-position of the first tracking object in the field of view, measuring a first maximum brightness of the first tracking object, calculating a first depth of the first tracking object using the first maximum brightness, detecting a second tracking object on the handheld device in the field of view, calculating a second x-position and a second y-position of the second tracking object in the field of view, measuring a second maximum brightness of the second tracking object, and calculating a second depth of the second tracking object using the second maximum brightness.

This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

Additional features and advantages of embodiments of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such embodiments. The features and advantages of such embodiments may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims, or may be learned by the practice of such embodiments as set forth hereinafter.