Patent Description:
An augmented reality (AR) device enables a user to observe a real-world scene while simultaneously view virtual content that may be aligned to items, images, objects, or environments in the field of view of the device. The AR device includes a partially transparent display that generates a composite image of the virtual content.

<CIT> describes methods and systems for see-through computer display systems with adjustable-zoom cameras positioned such that their respective capture fields-of-view at least partially overlap at a target distance.

The description that follows describes systems, methods, techniques, instruction sequences, and computing machine program products that illustrate example embodiments of the present subject matter. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide an understanding of various embodiments of the present subject matter. It will be evident, however, to those skilled in the art, that embodiments of the present subject matter may be practiced without some or other of these specific details. Examples merely typify possible variations. Unless explicitly stated otherwise, structures (e.g., structural Components, such as modules) are optional and may be combined or subdivided, and operations (e.g., in a procedure, algorithm, or other function) may vary in sequence or be combined or subdivided.

An AR application allows a user to experience information, such as in the form of a virtual object rendered in a display of an AR display device (also referred to as a display device). The rendering of the virtual object may be based on a position of the display device relative to a physical object or relative to a frame of reference (external to the display device) so that the virtual object correctly appears in the display. The virtual object appears aligned with a physical object as perceived by the user of the AR display device. Graphics (e.g., graphical elements containing instructions and guides) appear to be attached to a physical object of interest. In order to do this, the AR display device detects the physical object and tracks a pose of the AR display device relative to a position of the physical object. A pose identifies a position and orientation of the object relative to a frame of reference or relative to another object.

In one example, the AR display device includes a projector (e.g., Digital Light Projector (DLP)) that displays the virtual object on a screen of the AR display device. DLP projectors operate by projecting a light from a light source through a color wheel towards a DMD (Digital Micromirror Device). The DMD controls whether to reflect the colored light towards the screen of the AR display device. DLP projectors create color for the human eye by cycling through (R)ed, (G)reen, (B)lue bit-planes at very high rates (e.g., <NUM>). The sum of all bit-planes creates the impression of color for the human eye. The order of showing the bit-planes is optimized for each DLP projector individually (in terms of power and colors). As such, different DLP projectors will have different color cycle arrangements. Furthermore, depending on the frame rate of a DLP projector, the DLP projector repeats the bit plane sequence to fill the frame time (e.g., cycled). As such, each DLP projector is typically configured to optimize the bit-plane sequence (for power saving, color calibration, reduction of the rainbow artifacts (for wall projectors)).

The conditions of using a DLP projector to project on a stationary wall and using a DLP projector in a moving AR display device are fundamentally different. For example, when a user wears the AR display device and moves his/her head, the following effects occur:.

The present application describes a system and a method for configuring an operation of a DLP projector for use in an AR display device. By being able to predict where and how to render colors under user motion, the AR display device can effectively compensate motion-to-photon latency on a per color basis. The prediction can be accomplished by configuring the DLP projector to generate a single RGB repetition per frame, to identify a predefined color sequence of a light source component of the DLP projector, and to reduce a pixel persistence of the DLP projector. By changing the operation of the DLP projector as presently described results in higher AR image quality (e.g., virtual objects will not dissolve or be shown multiple times per frame, text in AR space will become more readable).

In one example embodiment, a method for configuring a digital light projector (DLP) of an augmented reality (AR) display device is described. A light source component of the DLP projector is configured to generate a single red-green-blue color sequence repetition per image frame. The AR display device identifies a color sequence of the light source component of the DLP projector and tracks a motion of the AR display device. The AR display device adjusts an operation of the DLP projector based on the single red-green-blue color sequence repetition, the color sequence of the light source component of the DLP projector, and the motion of the AR display device.

In another example embodiment, the method further comprises determining an adjusted pixel persistence value based on the identified color sequence and the single red-green-blue color sequence repetition per image frame; replacing the default pixel persistence value with the adjusted pixel persistence value; and operating the DLP projector with the adjusted pixel persistence value.

As a result, one or more of the methodologies described herein facilitate solving the technical problem of image ghosting, colors breakup, and high pixel persistence of a DLP projector mounted on a mobile unit by configuring the DLP projector to generate a single red-green-blue color sequence repetition per image frame, to identify a color sequence of the light source component, and to reduce a pixel persistence. The presently described method provides an improvement to an operation of the DLP projector by providing operation configurations. As such, one or more of the methodologies described herein may obviate a need for certain efforts or computing resources. Examples of such computing resources include Processor cycles, network traffic, memory usage, data storage capacity, power consumption, network bandwidth, and cooling capacity.

<FIG> is a network diagram illustrating a network environment <NUM> suitable for operating an AR display device <NUM>, according to some example embodiments. The network environment <NUM> includes an AR display device <NUM> and a server <NUM>, communicatively coupled to each other via a network <NUM>. The AR display device <NUM> and the server <NUM> may each be implemented in a computer system, in whole or in part, as described below with respect to <FIG>. The server <NUM> may be part of a network-based system. For example, the network-based system may be or include a cloud-based server system that provides additional information, such as virtual content (e.g., three-dimensional models of virtual objects) to the AR display device <NUM>.

A user <NUM> operates the AR display device <NUM>. The user <NUM> may be a human user (e.g., a human being), a machine user (e.g., a computer configured by a software program to interact with the AR display device <NUM>), or any suitable combination thereof (e.g., a human assisted by a machine or a machine supervised by a human). The user <NUM> is not part of the network environment <NUM>, but is associated with the AR display device <NUM>.

The AR display device <NUM> may be a computing device with a display such as a smartphone, a tablet computer, or a wearable computing device (e.g., glasses). The computing device may be hand-held or may be removable mounted to a head of the user <NUM>. In one example, the display may be a screen that displays what is captured with a camera of the AR display device <NUM>. In another example, the display of the device may be transparent such as in lenses of wearable computing glasses.

The user <NUM> operates an application of the AR display device <NUM>. The application may include an AR application configured to provide the user <NUM> with an experience triggered by a physical object <NUM>, such as a two-dimensional physical object (e.g., a picture), a three-dimensional physical object (e.g., a statue), a location (e.g., in a facility), or any references (e.g., perceived corners of walls or furniture) in the real-world physical environment. For example, the user <NUM> may point a camera of the AR display device <NUM> to capture an image of the physical object <NUM>. The image is tracked and recognized locally in the AR display device <NUM> using a local context recognition dataset module of the AR application of the AR display device <NUM>. The local context recognition dataset module may include a library of virtual objects associated with real-world physical objects or references. The AR application then generates additional information corresponding to the image (e.g., a three-dimensional model) and presents this additional information in a display of the AR display device <NUM> in response to identifying the recognized image. If the captured image is not recognized locally at the AR display device <NUM>, the AR display device <NUM> downloads additional information (e.g., the three-dimensional model) corresponding to the captured image, from a database of the server <NUM> over the network <NUM>.

In one example embodiment, the server <NUM> may be used to detect and identify the physical object <NUM> based on sensor data (e.g., image and depth data) from the AR display device <NUM>, determine a pose of the AR display device <NUM> and the physical object <NUM> based on the sensor data. The server <NUM> can also generate a virtual object based on the pose of the AR display device <NUM> and the physical object <NUM>. The server <NUM> communicates the virtual object to the AR display device <NUM>. The object recognition, tracking, and AR rendering can be performed on either the AR display device <NUM>, the server <NUM>, or a combination between the AR display device <NUM> and the server <NUM>.

Any of the machines, databases, or devices shown in <FIG> may be implemented in a general-purpose computer modified (e.g., configured or programmed) by software to be a special-purpose computer to perform one or more of the functions described herein for that machine, database, or device. For example, a computer system able to implement any one or more of the methodologies described herein is discussed below with respect to <FIG>. As used herein, a "database" is a data storage resource and may store data structured as a text file, a table, a spreadsheet, a relational database (e.g., an object-relational database), a triple store, a hierarchical data store, or any suitable combination thereof. Moreover, any two or more of the machines, databases, or devices illustrated in <FIG> may be combined into a single machine, and the functions described herein for any single machine, database, or device may be subdivided among multiple machines, databases, or devices.

The network <NUM> may be any network that enables communication between or among machines (e.g., server <NUM>), databases, and devices (e.g., AR display device <NUM>). Accordingly, the network <NUM> may be a wired network, a wireless network (e.g., a mobile or cellular network), or any suitable combination thereof. The network <NUM> may include one or more portions that constitute a private network, a public network (e.g., the Internet), or any suitable combination thereof.

<FIG> is a block diagram illustrating modules (e.g., components) of the AR display device <NUM>, according to some example embodiments. The AR display device <NUM> includes sensors <NUM>, a display system <NUM>, a processor <NUM>, and a storage device <NUM>. Examples of AR display device <NUM> include a wearable computing device, a desktop computer, a vehicle computer, a tablet computer, a navigational device, a portable media device, or a smart phone.

The sensors <NUM> include, for example, an optical sensor <NUM> (e.g., camera such as a color camera, a thermal camera, a depth sensor and one or multiple grayscales, global shutter tracking cameras) and an inertial sensor <NUM> (e.g., gyroscope, accelerometer). Other examples of sensors <NUM> include a proximity or location sensor (e.g., near field communication, GPS, Bluetooth, Wifi), an audio sensor (e.g., a microphone), or any suitable combination thereof. It is noted that the sensors <NUM> described herein are for illustration purposes and the sensors <NUM> are thus not limited to the ones described above.

The display system <NUM> includes a screen <NUM> and a DLP projector <NUM>. The DLP projector <NUM> projects an image of a virtual object on the screen <NUM>. In one example embodiment, the screen <NUM> may be transparent or semi-opaque so that the user <NUM> can see through the screen <NUM> (in AR use case). The DLP projector <NUM> is configured to operate with a predictable color sequence, a single RGB color cycle per frame, and a shorter pixel persistence. The DLP projector <NUM> is described in more detail below with respect to <FIG>.

The processor <NUM> includes an AR application <NUM>, a tracking system <NUM>, and a DLP controller <NUM>. The AR application <NUM> detects and identifies a physical environment or the physical object <NUM> using computer vision. The AR application <NUM> retrieves a virtual object (e.g., 3D object model) based on the identified physical object <NUM> or physical environment. The AR application <NUM> renders the virtual object in the display system <NUM>. For an AR application, the AR application <NUM> includes a local rendering engine that generates a visualization of a virtual object overlaid (e.g., superimposed upon, or otherwise displayed in tandem with) on an image of the physical object <NUM> captured by the optical sensor <NUM>. A visualization of the virtual object may be manipulated by adjusting a position of the physical object <NUM> (e.g., its physical location, orientation, or both) relative to the optical sensor <NUM>. Similarly, the visualization of the virtual object may be manipulated by adjusting a pose of the AR display device <NUM> relative to the physical object <NUM>.

In one example embodiment, the AR application <NUM> includes a contextual local image recognition module (not shown) configured to determine whether the captured image matches an image locally stored in a local database (e.g., storage device <NUM>) of images and corresponding additional information (e.g., virtual model and interactive features) on the AR display device <NUM>. In one example, the contextual local image recognition module retrieves a primary content dataset from the server <NUM>, and generates and updates a contextual content dataset based on an image captured with the AR display device <NUM>.

The tracking system <NUM> tracks the pose (e.g., position and orientation) of the AR display device <NUM> relative to the real world environment <NUM> using optical sensors (e.g., depth-enabled 3D camera, image camera), inertia sensors (e.g., gyroscope, accelerometer), wireless sensors (Bluetooth, Wi-Fi), GPS sensor, and/or audio sensor to determine the location of the AR display device <NUM> within the real world environment <NUM>. The tracking system <NUM> includes, for example, accesses inertial sensor data from the inertial sensor <NUM>, optical sensor data from the optical sensor <NUM>, and determines its pose based on the combined inertial sensor data and the optical sensor data. In another example, the tracking system <NUM> determines a pose (e.g., location, position, orientation) of the AR display device <NUM> relative to a frame of reference (e.g., real world environment <NUM>). In another example, the tracking system <NUM> includes a visual odometry system that estimates the pose of the AR display device <NUM> based on 3D maps of feature points from the inertial sensor data and the optical sensor data.

The DLP controller <NUM> communicates data signals to the DLP projector <NUM> to project the virtual content onto the screen <NUM> (e.g., transparent display). The DLP controller <NUM> includes a hardware that converts signals from the AR application <NUM> to display signals for the DLP projector <NUM>. In one example embodiment, the DLP controller <NUM> is part of the processor <NUM>. In another example embodiment, the DLP controller <NUM> is part of the DLP projector <NUM>.

In one example embodiment, the DLP controller <NUM> configures the DLP projector <NUM> to operate with a predictable color sequence, a single RGB color cycle per frame, and a shorter pixel persistence. For example, the DLP controller <NUM> determines or identifies the color sequence pattern of the DLP projector <NUM>. The DLP controller <NUM> directs the light source (or a color filter system) of the DLP projector <NUM> to produce a single color cycle per frame. The DLP controller <NUM> also directs a Digital Micro-mirror Device (DMD) of the DLP projector <NUM> to generate a shorter pixel persistence. The DLP controller <NUM> is described in more detail below with respect to <FIG>.

The storage device <NUM> stores virtual object content <NUM> and DLP configuration settings <NUM>. The virtual object content <NUM> includes, for example, a database of visual references (e.g., images) and corresponding experiences (e.g., three-dimensional virtual objects, interactive features of the three-dimensional virtual objects). In one example embodiment, the storage device <NUM> includes a primary content dataset, a contextual content dataset, and a visualization content dataset. The primary content dataset includes, for example, a first set of images and corresponding experiences (e.g., interaction with three-dimensional virtual object models). For example, an image may be associated with one or more virtual object models. The primary content dataset may include a core set of images. The core set of images may include a limited number of images identified by the server <NUM>. For example, the core set of images may include the images depicting covers of the ten most viewed physical objects and their corresponding experiences (e.g., virtual objects that represent the ten most viewed physical objects). In another example, the server <NUM> may generate the first set of images based on the most popular or often scanned images received at the server <NUM>. Thus, the primary content dataset does not depend on physical objects or images obtained by the optical sensor <NUM>.

The contextual content dataset includes, for example, a second set of images and corresponding experiences (e.g., three-dimensional virtual object models) retrieved from the server <NUM>. For example, images captured with the AR display device <NUM> that are not recognized (e.g., by the server <NUM>) in the primary content dataset are submitted to the server <NUM> for recognition. If the captured image is recognized by the server <NUM>, a corresponding experience may be downloaded at the AR display device <NUM> and stored in the contextual content dataset. Thus, the contextual content dataset relies on the context in which the AR display device <NUM> has been used. As such, the contextual content dataset depends on objects or images scanned by AR display device <NUM>.

The DLP configuration settings <NUM> include, for example, settings for the DLP projector <NUM> and/or determined by the DLP controller <NUM>. Example of settings include RGB bit-planes cycle rate, frame rate, color sequence, and pixel persistence time.

Any one or more of the modules described herein may be implemented using hardware (e.g., a Processor of a machine) or a combination of hardware and software. For example, any module described herein may configure a Processor to perform the operations described herein for that module. Moreover, any two or more of these modules may be combined into a single module, and the functions described herein for a single module may be subdivided among multiple modules. Furthermore, according to various example embodiments, modules described herein as being implemented within a single machine, database, or device may be distributed across multiple machines, databases, or devices.

<FIG> is a block diagram illustrating the DLP projector <NUM> in accordance with one example embodiment. The DLP controller <NUM> includes a light source <NUM> (also referred to as light source component), a condensing lens <NUM>, a shaping lens <NUM>, a DMD <NUM>, and a projection lens <NUM>.

The light source <NUM> includes, for example, a pressurized light bulb, a laser, or a high-powered LED. In one example embodiment, the light source <NUM> includes three colored LEDs: a blue LED <NUM>, a red LED <NUM>, and a green LED <NUM>. Each colored LED emits a colored light at its corresponding collimating lens (e.g., collimating lens <NUM>, collimating lens <NUM>, collimating lens <NUM>).

The DLP controller <NUM> interfaces with the light source <NUM> of the DLP projector <NUM> and controls the light source <NUM> to generate a single RGB repetition per frame. In one example embodiment, the DLP controller <NUM> interfaces with the light source <NUM> and identifies the color sequence of the light source <NUM>. For example, the DLP controller <NUM> queries the DLP projector <NUM> and identifies a model of the DLP projector <NUM>. The DLP controller <NUM> identifies the color sequence of the light source <NUM> based on the model of the DLP projector <NUM>.

In another example embodiment, the light source <NUM> includes for example, a white light source (not shown) and a color wheel (not shown) that is divided into primary colors (red, green, and blue). The color wheel rotates at a high speed (e.g., <NUM> RPM). The DLP controller <NUM> synchronizes the rotating motion of the color wheel so that the green component is displayed on the DMD when the green section of the color wheel is in front of the lamp. The same is true for the red, blue and other sections. The colors are displayed sequentially at a sufficiently high rate that the observer sees a composite (full color) image. Black color is produced by directing unused light away from the light source <NUM>. For example, the unused light is scattered to reflect and dissipate on the interior walls of the DMD <NUM> or projection lens <NUM>. The DLP controller <NUM> operates the light source <NUM> so that the color wheel rotates one RGB cycle per frame.

The condensing lens <NUM> focuses the light from the light source <NUM> onto the shaping lens <NUM>. The shaping lens <NUM> diffuses the light from the light source <NUM> to the DMD <NUM>. The DMD <NUM> includes hundreds of individual micromirrors. Digital signals that represent <NUM> and <NUM> drive those micromirrors to rotate to selected angles to reflect unnecessary light, and direct the required light to the projection lens <NUM>. Through persistence of visual, lights of different colors are synthesized to become a colored image to the human eyes. In one example embodiment, the DLP controller <NUM> controls the DMD <NUM> to reduce persistence of each pixel. Persistence is the time each pixel remains lit. High persistence (e.g., <NUM> at <NUM>) causes blurring and smearing of the images. The DLP controller <NUM> reduces the persistence of each pixel to, for example, less than <NUM>.

<FIG> illustrates the DLP controller <NUM> in accordance with one example embodiment. The DLP controller <NUM> includes a motion color artifact compensation module <NUM> and a low persistence module <NUM>. The motion color artifact compensation module <NUM> reduces the color artifact produced by a motion of the AR display device <NUM>. For example, as the user <NUM> moves his head (with the AR display device <NUM> mounted to his head) a displayed virtual content will break up in its base colors (RGB), more precisely the color sequence will become visible.

DLP projectors utilizing a mechanical spinning color wheel exhibit this color break up also known as the "rainbow effect". This is best described as brief flashes of perceived red, blue, and green "shadows" observed most often when the projected content features high contrast areas of moving bright or white objects on a mostly dark or black background. Brief visible separation of the colors can also be apparent when the viewer moves their eyes quickly across the projected image. Typically, the fast the user moves his eyes/head, the further apart the color appear.

The motion color artifact compensation module <NUM> reduces or eliminates the rainbow effect by compensating for color artifact based on predictable data. In other words, the motion color artifact compensation module <NUM> predicts where and how to render colors under user motion, and compensates motion-to-photon latency on a per color basis. In one example embodiment, the motion color artifact compensation module <NUM> includes a color cycle module <NUM> and a color sequence module <NUM>.

The color cycle module <NUM> configures the light source <NUM> to generate only one single repetition of the base colors (RGB) per image frame. For example, a conventional light source <NUM> produces four color RGB-RGB-RGB-RGB (e.g., at about <NUM>) per frame. The multiple color cycles result in stutter effects because the picture is seen four times at different positions. This stutter effect is especially exacerbated during head motion of the AR display device <NUM> while virtual content is displayed.

The color sequence module <NUM> identifies or determines a color sequence of the light source <NUM>. As previously described, in a conventional DLP projector, as the user moves his head, a displayed virtual content will break up in its base colors, more precisely the color sequence will become visible. For example, a simple RGB sequence will bleed its three colors. The faster the user moves his head, the further apart the colors will appear. High frequency color sequences can be used to offset the color bleeding. However, the high frequency can lead to motion blur and unreadable text. The color sequence module <NUM> identifies the color sequence (R, G, and B) of the light source <NUM> and counters the effect of the color breakup based on the predicted color sequence for each frame.

The low persistence module <NUM> reduces persistence of each pixel by controlling the DMD <NUM> to direct light from the light source <NUM> away from the projection lens <NUM>. In one example, the low persistence module <NUM> reduces the persistence of each pixel to, for example, less than <NUM>. In another example embodiment, the DLP controller <NUM> controls the DMD <NUM> to show black (direct the light away from the projection lens <NUM>) <NUM>% of the frame time, resulting in a shifting of individual color planes.

<FIG> is a chart illustrating image ghosting effects in accordance with one embodiment. Chart <NUM> illustrates an example of displayed signal based on repeated color cycles in a single frame. Chart <NUM> illustrates an example of perceived signal (by the user) based on the repeated color cycles in a single frame.

Chart <NUM> illustrates an example of displayed signal based on a single RGB cycle repetition in a single frame. Chart <NUM> illustrates an example of perceived signal (by the user) based on the single-color cycle in a single frame.

<FIG> illustrates an example of a rainbow effect from conventional DLP projectors. DLP projectors utilizing a mechanical spinning color wheel may exhibit an anomaly known as the "rainbow effect". This is best described as brief flashes of perceived red, blue, and green "shadows" observed most often when the projected content features high contrast areas of moving bright or white objects on a mostly dark or black background. Common examples are the scrolling end credits of many movies, and also animations with moving objects surrounded by a thick black outline. Brief visible separation of the colors can also be apparent when the viewer moves their eyes quickly across the projected image. Some people perceive these rainbow artifacts frequently, while others may never see them at all.

This effect is caused by the way the eye follows a moving object on the projection. When an object on the screen moves, the eye follows the object with a constant motion, but the projector displays each alternating color of the frame at the same location for the duration of the whole frame. So, while the eye is moving, it sees a frame of a specific color (red, for example). Then, when the next color is displayed (green, for example), although it gets displayed at the same location overlapping the previous color, the eye has moved toward the object's next frame target. Thus, the eye sees that specific frame color slightly shifted. Then, the third color gets displayed (blue, for example), and the eye sees that frame's color slightly shifted again. This effect is not perceived only for the moving object, but the whole picture.

Image <NUM> illustrates a rendered image. Image <NUM> illustrates a rainbow effect image as perceived by a user. Image <NUM> illustrates a rainbow effect image predicted by a color plane (e.g., identified color sequence of a single-color cycle in a single frame). Image <NUM> illustrates a perceived image resulting from compensation operations based on the predicted rainbow effect.

<FIG> is a chart illustrating a low color persistence effect in accordance with one example embodiment. Chart <NUM> illustrates color planes with all colors shifted together for each frame. Chart <NUM> illustrates color planes with colors shifted individually for each frame.

<FIG> is a block diagram illustrating modules (e.g., components) of the server <NUM>. The server <NUM> includes a sensor engine <NUM>, an object detection engine <NUM>, a rendering engine <NUM>, and a database <NUM>.

The sensor engine <NUM> interfaces and communicates with sensors <NUM> to obtain sensor data related to a pose (e.g., location and orientation) of the AR display device <NUM> relative to a frame of reference (e.g., the room or real world environment <NUM>) and to one or more objects (e.g., physical object <NUM>).

The object detection engine <NUM> accesses the sensor data from sensor engine <NUM>, to detect and identify the physical object <NUM> based on the sensor data. The rendering engine <NUM> generates virtual content that is displayed based on the pose of the AR display device <NUM> and the physical object <NUM>.

The database <NUM> includes a physical object dataset <NUM>, the virtual content dataset <NUM>, and the DLP projector dataset <NUM>. The physical object dataset <NUM> includes features of different physical objects. The virtual content dataset <NUM> includes virtual content associated with physical objects. The DLP projector dataset <NUM> stores configuration settings of the DLP projector <NUM>.

<FIG> is a flow diagram illustrating a method for configuring a DLP projector in accordance with one example embodiment. Operations in the routine <NUM> may be performed by the DLP controller <NUM>, using Components (e.g., modules, engines) described above with respect to <FIG>. Accordingly, the routine <NUM> is described by way of example with reference to the DLP controller <NUM>. However, it shall be appreciated that at least some of the operations of the routine <NUM> may be deployed on various other hardware configurations or be performed by similar Components residing elsewhere.

In block <NUM>, the color cycle module <NUM> configures a color filter system (e.g., RGB LEDs) of a light source <NUM> of the DLP projector <NUM> to generate a single RGB repetition per frame. In block <NUM>, the color sequence module <NUM> configures the light source <NUM> of the DLP projector <NUM> to generate predictable color sequences. In block <NUM>, the low persistence module <NUM> configures the DMD <NUM> of the DLP projector <NUM> to reduce persistence of each pixel.

It is to be noted that other embodiments may use different sequencing, additional or fewer operations, and different nomenclature or terminology to accomplish similar functions. In some embodiments, various operations may be performed in parallel with other operations, either in a synchronous or asynchronous manner. The operations described herein were chosen to illustrate some principles of operations in a simplified form.

<FIG> is a flow diagram illustrating a method for operating a DLP projector in accordance with one example embodiment. Operations in the routine <NUM> may be performed by the DLP controller <NUM>, using Components (e.g., modules, engines) described above with respect to <FIG>. Accordingly, the routine <NUM> is described by way of example with reference to the DLP controller <NUM>. However, it shall be appreciated that at least some of the operations of the routine <NUM> may be deployed on various other hardware configurations or be performed by similar Components residing elsewhere. For example, some of the operations may be performed at the server <NUM>.

In block <NUM>, the color cycle module <NUM> generate one repetition of a color cycle in a bit-plane. In block <NUM>, the tracking system <NUM> detects a pose of the AR display device. In block <NUM>, the DLP projector <NUM> projects virtual content on the screen <NUM> based on one repetition of the color cycle at the detected pose.

In block <NUM>, the color cycle module <NUM> generates one repetition of a color cycle in a bit-plane. In block <NUM>, the color sequence module <NUM> identifies a color sequence of the light source <NUM>. In block <NUM>, the tracking system <NUM> detects a pose of the AR display device. In block <NUM>, the motion color artifact compensation module <NUM> predicts a color break up based on the color sequence. In block <NUM>, the motion color artifact compensation module <NUM> counters the predicted color break up based on the color sequence.

<FIG> is a flow diagram illustrating a method for adjusting a pixel persistence in accordance with one example embodiment. Operations in the routine <NUM> may be performed by the DLP controller <NUM>, using Components (e.g., modules, engines) described above with respect to <FIG>. Accordingly, the routine <NUM> is described by way of example with reference to the DLP controller <NUM>. However, it shall be appreciated that at least some of the operations of the routine <NUM> may be deployed on various other hardware configurations or be performed by similar Components residing elsewhere. For example, some of the operations may be performed at the server <NUM>.

In block <NUM>, the low persistence module <NUM> identifies default pixel persistence time. In block <NUM>, the tracking system <NUM> predicts motion of the AR display device <NUM>. In block <NUM>, the color cycle module <NUM> configures the DLP projector <NUM> to display one color per cycle. In block <NUM>, the low persistence module <NUM> adjusts a pixel persistence time of the DLP projector <NUM> from the default pixel persistence time to display black <NUM>% of the frame time.

The software architecture <NUM> is supported by hardware such as a machine <NUM> that includes Processors <NUM>, memory <NUM>, and I/O Components <NUM>.

The operating system <NUM> manages hardware resources and provides common services. The operating system <NUM> includes, for example, a kernel <NUM>, services <NUM>, and drivers <NUM>. The kernel <NUM> acts as an abstraction layer between the hardware and the other software layers. For example, the kernel <NUM> provides memory management, Processor management (e.g., scheduling), Component management, networking, and security settings, among other functionalities. The services <NUM> can provide other common services for the other software layers. The drivers <NUM> are responsible for controlling or interfacing with the underlying hardware. For instance, the drivers <NUM> can include display drivers, camera drivers, BLUETOOTH® or BLUETOOTH® Low Energy drivers, flash memory drivers, serial communication drivers (e.g., Universal Serial Bus (USB) drivers), WI-FI® drivers, audio drivers, power management drivers, and so forth.

The libraries <NUM> provide a low-level common infrastructure used by the applications <NUM>. The libraries <NUM> can include system libraries <NUM> (e.g., C standard library) that provide functions such as memory allocation functions, string manipulation functions, mathematic functions, and the like. In addition, the libraries <NUM> can include API libraries <NUM> such as media libraries (e.g., libraries to support presentation and manipulation of various media formats such as Moving Picture Experts Group-<NUM> (MPEG4), Advanced Video Coding (H. <NUM> or AVC), Moving Picture Experts Group Layer-<NUM> (MP3), Advanced Audio Coding (AAC), Adaptive Multi-Rate (AMR) audio codec, Joint Photographic Experts Group (JPEG or JPG), or Portable Network Graphics (PNG)), graphics libraries (e.g., an OpenGL framework used to render in two dimensions (2D) and three dimensions (3D) in a graphic content on a display), database libraries (e.g., SQLite to provide various relational database functions), web libraries (e.g., WebKit to provide web browsing functionality), and the like. The libraries <NUM> can also include a wide variety of other libraries <NUM> to provide many other APIs to the applications <NUM>.

The frameworks <NUM> provide a high-level common infrastructure that is used by the applications <NUM>. For example, the frameworks <NUM> provide various graphical user interface (GUI) functions, high-level resource management, and high-level location services. The frameworks <NUM> can provide a broad spectrum of other APIs that can be used by the applications <NUM>, some of which may be specific to a particular operating system or platform.

In an example embodiment, the applications <NUM> may include a home application <NUM>, a contacts application <NUM>, a browser application <NUM>, a book reader application <NUM>, a location application <NUM>, a media application <NUM>, a messaging application <NUM>, a game application <NUM>, and a broad assortment of other applications such as a third-party application <NUM>. The applications <NUM> are programs that execute functions defined in the programs. Various programming languages can be employed to create one or more of the applications <NUM>, structured in a variety of manners, such as object-oriented programming languages (e.g., Objective-C, Java, or C++) or procedural programming languages (e.g., C or assembly language). In a specific example, the third-party application <NUM> (e.g., an application developed using the ANDROID™ or IOS™ software development kit (SDK) by an entity other than the vendor of the particular platform) may be mobile software running on a mobile operating system such as IOS™, ANDROID™, WINDOWS® Phone, or another mobile operating system. In this example, the third-party application <NUM> can invoke the API calls <NUM> provided by the operating system <NUM> to facilitate functionality described herein.

<FIG> is a diagrammatic representation of the machine <NUM> within which instructions <NUM> (e.g., software, a program, an application, an applet, an app, or other executable code) for causing the machine <NUM> to perform any one or more of the methodologies discussed herein may be executed. For example, the instructions <NUM> may cause the machine <NUM> to execute any one or more of the methods described herein. The instructions <NUM> transform the general, non-programmed machine <NUM> into a particular machine <NUM> programmed to carry out the described and illustrated functions in the manner described. The machine <NUM> may operate as a standalone device or may be coupled (e.g., networked) to other machines. In a networked deployment, the machine <NUM> may operate in the capacity of a server machine or a client machine in a server-client network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The machine <NUM> may comprise, but not be limited to, a server computer, a client computer, a personal computer (PC), a tablet computer, a laptop computer, a netbook, a set-top box (STB), a PDA, an entertainment media system, a cellular telephone, a smart phone, a mobile device, a wearable device (e.g., a smart watch), a smart home device (e.g., a smart appliance), other smart devices, a web appliance, a network router, a network switch, a network bridge, or any machine capable of executing the instructions <NUM>, sequentially or otherwise, that specify actions to be taken by the machine <NUM>. Further, while only a single machine <NUM> is illustrated, the term "machine" shall also be taken to include a collection of machines that individually or jointly execute the instructions <NUM> to perform any one or more of the methodologies discussed herein.

The machine <NUM> may include Processors <NUM>, memory <NUM>, and I/O Components <NUM>, which may be configured to communicate with each other via a bus <NUM>. In an example embodiment, the Processors <NUM> (e.g., a Central Processing Unit (CPU), a Reduced Instruction Set Computing (RISC) Processor, a Complex Instruction Set Computing (CISC) Processor, a Graphics Processing Unit (GPU), a Digital Signal Processor (DSP), an ASIC, a Radio-Frequency Integrated Circuit (RFIC), another Processor, or any suitable combination thereof) may include, for example, a Processor <NUM> and a Processor <NUM> that execute the instructions <NUM>. The term "Processor" is intended to include multi-core Processors that may comprise two or more independent Processors (sometimes referred to as "cores") that may execute instructions contemporaneously. Although <FIG> shows multiple Processors <NUM>, the machine <NUM> may include a single Processor with a single core, a single Processor with multiple cores (e.g., a multi-core Processor), multiple Processors with a single core, multiple Processors with multiples cores, or any combination thereof.

The memory <NUM> includes a main memory <NUM>, a static memory <NUM>, and a storage unit <NUM>, both accessible to the Processors <NUM> via the bus <NUM>. The instructions <NUM> may also reside, completely or partially, within the main memory <NUM>, within the static memory <NUM>, within machine-readable medium <NUM> within the storage unit <NUM>, within at least one of the Processors <NUM> (e.g., within the Processor's cache memory), or any suitable combination thereof, during execution thereof by the machine <NUM>.

The I/O Components <NUM> may include a wide variety of Components to receive input, provide output, produce output, transmit information, exchange information, capture measurements, and so on. The specific I/O Components <NUM> that are included in a particular machine will depend on the type of machine. For example, portable machines such as mobile phones may include a touch input device or other such input mechanisms, while a headless server machine will likely not include such a touch input device. It will be appreciated that the I/O Components <NUM> may include many other Components that are not shown in <FIG>. In various example embodiments, the I/O Components <NUM> may include output Components <NUM> and input Components <NUM>. The output Components <NUM> may include visual Components (e.g., a display such as a plasma display panel (PDP), a light emitting diode (LED) display, a liquid crystal display (LCD), a projector, or a cathode ray tube (CRT)), acoustic Components (e.g., speakers), haptic Components (e.g., a vibratory motor, resistance mechanisms), other signal generators, and so forth. The input Components <NUM> may include alphanumeric input Components (e.g., a keyboard, a touch screen configured to receive alphanumeric input, a photo-optical keyboard, or other alphanumeric input Components), point-based input Components (e.g., a mouse, a touchpad, a trackball, a joystick, a motion sensor, or another pointing instrument), tactile input Components (e.g., a physical button, a touch screen that provides location and/or force of touches or touch gestures, or other tactile input Components), audio input Components (e.g., a microphone), and the like.

In further example embodiments, the I/O Components <NUM> may include biometric Components <NUM>, motion Components <NUM>, environmental Components <NUM>, or position Components <NUM>, among a wide array of other Components. For example, the biometric Components <NUM> include Components to detect expressions (e.g., hand expressions, facial expressions, vocal expressions, body gestures, or eye tracking), measure biosignals (e.g., blood pressure, heart rate, body temperature, perspiration, or brain waves), identify a person (e.g., voice identification, retinal identification, facial identification, fingerprint identification, or electroencephalogram-based identification), and the like. The motion Components <NUM> include acceleration sensor Components (e.g., accelerometer), gravitation sensor Components, rotation sensor Components (e.g., gyroscope), and so forth. The environmental Components <NUM> include, for example, illumination sensor Components (e.g., photometer), temperature sensor Components (e.g., one or more thermometers that detect ambient temperature), humidity sensor Components, pressure sensor Components (e.g., barometer), acoustic sensor Components (e.g., one or more microphones that detect background noise), proximity sensor Components (e.g., infrared sensors that detect nearby objects), gas sensors (e.g., gas detection sensors to detection concentrations of hazardous gases for safety or to measure pollutants in the atmosphere), or other Components that may provide indications, measurements, or signals corresponding to a surrounding physical environment. The position Components <NUM> include location sensor Components (e.g., a GPS receiver Component), altitude sensor Components (e.g., altimeters or barometers that detect air pressure from which altitude may be derived), orientation sensor Components (e.g., magnetometers), and the like.

Communication may be implemented using a wide variety of technologies. The I/O Components <NUM> further include communication Components <NUM> operable to couple the machine <NUM> to a network <NUM> or devices <NUM> via a coupling <NUM> and a coupling <NUM>, respectively. For example, the communication Components <NUM> may include a network interface Component or another suitable device to interface with the network <NUM>. In further examples, the communication Components <NUM> may include wired communication Components, wireless communication Components, cellular communication Components, Near Field Communication (NFC) Components, Bluetooth® Components (e.g., Bluetooth® Low Energy), Wi-Fi® Components, and other communication Components to provide communication via other modalities. The devices <NUM> may be another machine or any of a wide variety of peripheral devices (e.g., a peripheral device coupled via a USB).

Moreover, the communication Components <NUM> may detect identifiers or include Components operable to detect identifiers. For example, the communication Components <NUM> may include Radio Frequency Identification (RFID) tag reader Components, NFC smart tag detection Components, optical reader Components (e.g., an optical sensor to detect one-dimensional bar codes such as Universal Product Code (UPC) bar code, multi-dimensional bar codes such as Quick Response (QR) code, Aztec code, Data Matrix, Dataglyph, MaxiCode, PDF417, Ultra Code, UCC RSS-2D bar code, and other optical codes), or acoustic detection Components (e.g., microphones to identify tagged audio signals). In addition, a variety of information may be derived via the communication Components <NUM>, such as location via Internet Protocol (IP) geolocation, location via Wi-Fi® signal triangulation, location via detecting an NFC beacon signal that may indicate a particular location, and so forth.

The various memories (e.g., memory <NUM>, main memory <NUM>, static memory <NUM>, and/or memory of the Processors <NUM>) and/or storage unit <NUM> may store one or more sets of instructions and data structures (e.g., software) embodying or used by any one or more of the methodologies or functions described herein. These instructions (e.g., the instructions <NUM>), when executed by Processors <NUM>, cause various operations to implement the disclosed embodiments.

The instructions <NUM> may be transmitted or received over the network <NUM>, using a transmission medium, via a network interface device (e.g., a network interface Component included in the communication Components <NUM>) and using any one of a number of well-known transfer protocols (e.g., hypertext transfer protocol (HTTP)). Similarly, the instructions <NUM> may be transmitted or received using a transmission medium via the coupling <NUM> (e.g., a peer-to-peer coupling) to the devices <NUM>.

Although an embodiment has been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader scope of the present disclosure. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof, show by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims.

Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term "invention" merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

Claim 1:
A method for configuring a digital light projector, DLP, of an augmented reality, AR, display device comprising:
configuring a light source component (<NUM>) of the DLP projector (<NUM>) to generate a single red-green-blue color sequence repetition per image frame;
identifying (<NUM>) a color sequence of the light source component (<NUM>) of the DLP projector (<NUM>);
tracking (<NUM>) a motion of the AR display device (<NUM>); and
adjusting an operation of the DLP projector (<NUM>) based on the single red-green-blue color sequence repetition, the color sequence of the light source component (<NUM>) of the DLP projector (<NUM>), and the motion of the AR display device (<NUM>);
wherein adjusting the operation of the DLP projector (<NUM>) further comprises:
generating (<NUM>) one repetition of the color sequence;
identifying (<NUM>) the color sequence;
detecting (<NUM>) a pose of the AR display device;
predicting (<NUM>), based on the pose and the identified color sequence, a motion artifact;
generating a counter artifact that offsets the motion artifact; and
causing the DLP projector (<NUM>) to display the counter artifact while reducing a pixel persistence time of the DLP projector (<NUM>) from a default pixel persistence time to an adjusted pixel persistence time by controlling a digital micromirror device, DMD, of the DLP projector (<NUM>) to light a pixel for the adjusted pixel persistence time, wherein the pixel persistence time is the time for which each pixel remains lit;
characterized in that
the counter artifact comprises shifting each bit plane of each color plane individually based on the adjusted pixel persistence value.