Patent Publication Number: US-2021181533-A1

Title: Modular prescription augmented reality display

Description:
BACKGROUND 
     Augmented reality (“AR”) is an emerging field in which graphical elements are added to an image of the real world. Augmented reality displays can be constructed in a number of ways. For example, some handheld devices implement a type of augmented reality by capturing an image of the real world with a camera, adding computer-generated images to the captured image, and then displaying the augmented image on the mobile display. Other devices attempt to add a generated image to eyeglasses similar to a heads-up display. Creating effective AR displays is particularly difficult when the user of the display uses a form of corrective vision. Allowing for use with existing corrective eyewear often results in a bulky and cumbersome AR display, and using the AR display without corrective eyewear results in a blurry or unclear display being presented to the wearer. Since a significant portion of the population relies on prescription eyewear to see properly, producing an effective AR display that allows for vision correction is an important problem. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various techniques will be described with reference to the drawings, in which: 
         FIG. 1  illustrates an example of a prescription augmented reality display worn by a user, in accordance with an embodiment; 
         FIG. 2  illustrates an example of an augmented reality display integrated into prescription eyeglasses, in accordance with an embodiment; 
         FIG. 3  illustrates an example of an image produced by an augmented reality display, in accordance with an embodiment; 
         FIG. 4  illustrates an example of a lens assembly of an augmented reality display, in accordance with an embodiment; 
         FIG. 5  illustrates an example of a display unit and lens geometry that combines the output of the display unit with a prescription lens to form an augmented reality display, in accordance with an embodiment; 
         FIG. 6  illustrates an example of a prescription lens assembly with an image combiner, in accordance with an embodiment; 
         FIG. 7  illustrates an example of prescription augmented reality for a myopic eye, in accordance with an embodiment; 
         FIG. 8  illustrates an example of a spot diagram for a prescription lens with and without CYL power, in accordance with an embodiment; 
         FIG. 9  illustrates an example of the angular resolution of a foveated AR display, in accordance with an embodiment; 
         FIG. 10  illustrates an example of a process that, as a result of being performed, optimizes a prescription lens of a prescription AR display, in accordance with an embodiment; 
         FIG. 11  illustrates an example of a process that, as a result of being performed, optimizes an AR display of a prescription AR display, in accordance with an embodiment; 
         FIG. 12  illustrates an example of a design trade-off space for lens thickness and eye box size for a prescription AR display, in accordance with an embodiment; 
         FIG. 13  illustrates an example of a correlation between a display panel shift and an image plane shift for a prescription AR display, in accordance with an embodiment; 
         FIG. 14  illustrates an example of a design trade-off space for a vertical field of view and eye relief for a prescription AR display, in accordance with an embodiment; 
         FIG. 15  illustrates an example of an AR display with an adjustable image position, in accordance with an embodiment; 
         FIG. 16  illustrates an example of the angular resolution of a foveated display, in accordance with an embodiment; 
         FIG. 17  illustrates an example of a modular augmented reality display with an upward configuration that allows the separate use of a prescription eyeglass component, in accordance with an embodiment; 
         FIG. 18  illustrates an example of a modular augmented reality display with an outward configuration that allows the separate use of a prescription eyeglass component, in accordance with an embodiment; 
         FIG. 19  illustrates an example of a detachable display assembly of an augmented reality display, in accordance with an embodiment; 
         FIG. 20  illustrates an example of a modular augmented reality display being worn by a user, in accordance with an embodiment; 
         FIG. 21  illustrates an example of a modular augmented reality display that communicates with a computer server, in accordance with an embodiment; 
         FIG. 22  illustrates an example of a parallel processing unit (“PPU”), in accordance with an embodiment; 
         FIG. 23  illustrates an example of a general processing cluster (“GPC”), in accordance with one embodiment; 
         FIG. 24  illustrates an example of a memory partition unit, in accordance with one embodiment; 
         FIG. 25  illustrates an example of a streaming multi-processor, in accordance with one embodiment; and 
         FIG. 26  illustrates a computer system in which the various examples can be implemented, in accordance with one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The present document describes a modular augmented reality (“AR”) display that includes a prescription lens for vision correction. In at least one embodiment, the prescription lens is integrated into a frame, and the lens-frame assembly can be detached from AR components of the AR display so that the lens-frame assembly can be used as a set of conventional prescription eyewear without AR functionality. Removing the AR components lightens the eyewear sufficiently so that the eyewear is more comfortable in extended use. In various examples, the electronic components are removably attached using magnets or clips to the lens-frame assembly. In at least one embodiment, the removable AR components include one or more organic light emitting diode (“OLED”) displays and one or more lenses that shape and direct images into the edge of the prescription lens, thereby providing AR image content to the wearer. 
     In some examples, the AR components include a support pack with a battery, computer system, and wireless interface. In at least one embodiment, a server computer system sends display information to the computer system on the support pack via the wireless interface, and the computer system sends the information to the AR components mounted on the eyewear. In various embodiments, the support pack can be attached to a belt, pant waistline, or article of clothing worn by the user. In some examples, the support pack may be placed in a user&#39;s pocket. In at least one embodiment, the support pack is connected to AR components on the lens-frame assembly via a wired connection that carries power and data signals. By moving the battery and computer components to the support pack, the weight of the AR display on the wearer&#39;s head is reduced, increasing comfort in long-term use. 
     In at least one embodiment, the AR display presents virtual images in real-world scenes while preserving the viewer&#39;s natural vision. In at least one embodiment, an optical structure is provided that has a slim form factor, a high-resolution, large field-of-view (FOV), large eye box, and variable focus. In an embodiment, the diverse spectrum of human head shape and eye structure aggravates this challenge further. Various users have different interpupillary distance (IPD, 54-68 mm) and nose shapes, which raise the bar on eye box and eye relief coverage beyond the requirement for a single user. More than 40% of the population uses special aids for vision correction caused by myopia, hyperopia, astigmatism, and presbyopia. Unlike other designs that may be used with prescription eyeglasses, at least one embodiment described herein provides an AR display that includes corrective lenses adapted to the viewer&#39;s prescription. By integrating the viewer&#39;s prescription into the AR display, overall weight and size of the system can be improved significantly. 
     In an embodiment, a prescription-embedded AR display is provided. In an embodiment, an optical design for the AR display utilizes a prescription lens as a waveguide for the AR display. In an embodiment, a free-form image combiner is embedded in the prescription lens, allowing the one-piece lens to both deliver virtual scenes and also correct the vision of a real-world scene simultaneously. In at least one embodiment, the image combiner is a half-silvered mirror or semi-reflective film. In an example of an embodiment, a shape for the prescription lens is provided for a modified myopia eye model. In an embodiment, a free-form image combiner, in-coupling prism, and beam-shaping lens are optimized based on each individual prescription lens. In at least one embodiment, a customized ergonomic eye-glasses design is achieved by using 3D facial scanning. In at least one embodiment, a Prescription AR prototype with a 5-mm thick lens provides 1 diopter (1D) vision correction, 23 cycles per degree (cpd) angular resolution at center, 4 mm eye box, and varifocal (0D-2D) capability. In at least one embodiment, the prototype is lightweight (169 g for dynamic and 79 g for static prototype), has 70% transparency, protects a user&#39;s privacy, and enables eye-contact interaction with surroundings. 
       FIG. 1  illustrates an example of a prescription augmented reality display worn by a user, in accordance with an embodiment. In at least one embodiment, the wearer  102  equips the augmented reality display in a manner similar to conventional eyeglasses. In at least one embodiment, at least one augmented reality lens  104  is held by a frame  106  which is worn by the wearer  102 . In at least one embodiment, two augmented reality lenses are provided in the augmented reality display to provide binocular vision of the augmented images. 
     In at least one embodiment, the augmented reality display positions the lenses close to the wearer&#39;s face so that the eye relief and eye box of the display can be minimized. In at least one embodiment, the augmented reality lens  104  provides three regions through which the wearer can look. In at least one embodiment, a first region  108  at the top of the augmented reality lens and a third region  112  at the bottom of the augmented reality lens provide an optical correction in accordance with a corrective vision prescription of the wearer. In at least one embodiment, a second region  110  in the middle of the augmented reality lens includes an image combiner constructed from a half mirrored surface embedded within the lens. In at least one embodiment, an image injected down through the edge of the lens from a display within the frame is reflected internally within the lens until it comes in contact with the image combiner. In at least one embodiment, the image is redirected towards the eye of the wearer along with an image of the real world that is transmitted through the lens and the image combiner. In at least one embodiment, the first region  108  and the third region  112  are coated with a neutral density filter so that the image transmission through the lens is roughly even from the top to the bottom of the lens. In at least one embodiment, the view through the second region  110  includes both transmitted images from the real-world and images generated from the electronic display within the frame of the augmented reality display. 
     In at least one embodiment, the profile of the augmented reality lens  104  is adapted in accordance with a vision prescription of the wearer. In at least one embodiment, the image combiner is formed within the lens and has a surface profile that similarly presents an in-focus image in accordance with the vision correction needed by the wearer. In at least one embodiment, the position of the virtual image originating from within the display on the augmented reality display can be altered by moving the position of the display in relation to the frame either manually or by electronic servo. 
       FIG. 2  illustrates an example of an augmented reality display integrated into prescription eyeglasses, in accordance with an embodiment. In at least one embodiment, the augmented reality display is produced in an eyeglass form factor having a frame with two arms  202  and  204 . In at least one embodiment, a power and control unit  206  drives a pair of electronic displays mounted in the top of the frame. In at least one embodiment, the power and control unit  206  includes one or more buttons to allow control of the display by the wearer. In at least one embodiment, the power and control unit  206  includes a battery, processor, and graphical interface. In at least one embodiment, the processor and graphical interface may include a CPU or GPU as described in  FIGS. 16 through 20 . In at least one embodiment, the augmented reality display includes two lenses  208  and  210  that include an image combiner within each lens. In at least one embodiment, the image combiner combines the image transmitted through the lens with the image created by the electronic display. In at least one embodiment, the augmented reality display includes a beam-shaping lens and prism,  212  and  214 , in each lens that directs the image produced by the electronic display downward into the lens such that the image is internally reflected and directed to the image combiner of each lens. 
       FIG. 3  illustrates an example of an image produced by an augmented reality display, in accordance with an embodiment. In at least one embodiment, a first image  302  illustrates an image transmitted through the lens from the real-world to the wearer. In at least one embodiment, a second image  304  illustrates an augmented image seen by the wearer of the augmented reality display. In the example illustrated in  FIG. 3 , the second image includes a logo and lettering added by the image combiner and produced by an electronic display  306  on the augmented reality display. 
       FIG. 4  illustrates an example of a lens assembly of an augmented reality display, in accordance with an embodiment. In at least one embodiment, the augmented reality display includes a free-form image combiner  402  embedded within a prescription lens  404 . In at least one embodiment, the prescription lens  404  is fabricated in accordance with a vision correction prescription. In at least one embodiment, the free-form image combiner  402  is made by coating the interface between two parts of the prescription lens  404  with a half-silver material and joining the parts with optical glue. 
     In at least one embodiment, the lens assembly includes an in-coupling prism  406  and a beam-shaping lens  408  that, in combination, direct an image produced by a micro LED  412  into the edge of the prescription lens  404 . In at least one embodiment, the beam-shaping lens  408  is retained in position by a lens holder  410  secured to a frame of the augmented reality display. In at least one embodiment, the micro-LED is held in pace with a panel holder  414 . In at least one embodiment, the panel holder  414  includes a manual or electronic actuator that allows the micro-LED to be moved along the optical axis of the beam-shaping lens. In at least one embodiment, movement of the micro-LED panel is accomplished with a thumbscrew attached to the threaded rod. In at least one embodiment, movement of the micro LED panel is accomplished using an ultra-thin auto focus actuator module (“UTAF”). 
       FIG. 5  illustrates an example of a display unit and lens geometry that combines the output of the display unit with a prescription lens to form an augmented reality display, in accordance with an embodiment.  FIG. 5  illustrates a side view and the beam path of an embodiment. In at least one embodiment, a prescription lens  502  works both for vision-correction and as a wave-guide for an AR image produced by a micro display  504 . In at least one embodiment, light rays from the micro display  504  are refracted by a beam-shaping lens  506  and enter the prescription lens through an in-coupling prism  508  to create a magnified virtual image located a distance d i  from an eye  510 . In at least one embodiment, the virtual image depth can be dynamically changed from 0D to 2D by moving the micro display  504  axially (Δa). 
     In at least one embodiment, a prescription AR display optically corrects a user&#39;s vision with a prescription lens, and utilizes the prescription lens as a waveguide in an AR display system. As shown in  FIG. 5 , the top surface of the prescription lens of thickness t 1  is used as an entrance of the waveguide. In at least one embodiment, the light rays from a micro display of size w d ×h d  and resolution N x ×N y  located in front of the user&#39;s forehead with an angle θ d  are refracted by a bi-convex (R l1 , R l2 ) beam-shaping lens (refractive index: n 1 , thickness: t BSL ) located at a distance a from the micro display with the tilted angle θ l  and entered to the waveguide through an in-coupling prism (refractive index: n 1 ) located at d p  from the beam-shaping lens with the tilted angle θ p . In at least one embodiment, the in-coupling prism is composed by a set of a plano-concave and a convex-plano cylindrical lens. In at least one embodiment, the rays are refracted by a cylindrical lens (R cy , refractive index: n 2 ) located at t c  from the prism surface with the tilted angle θ c  and travel in the waveguide (refractive index: n 3 , tilted angle: θ w ) located at t w  from the cylindrical surface as shown in  FIG. 4 . In an embodiment, the light rays are internally reflected twice by the frontal surface (S f ) and the rear surface (S r ) of the prescription lens, reflected by a free-form half-mirror coated surface (S free , tilted angle: θ f ), and arrive at the pupil of the eye. In at least one embodiment, the in-coupling prism, cylindrical lens, upper part of the prescription lens, and lower part of the prescription lens are bonded by an optical adhesive, such that the prescription lens is comprised of two lens pieces: the main lens and the beam-shaping lens. In at least one embodiment, the enlarged virtual image of size w i ×h i  is located at distance d i  from the eye in the vision-corrected real scene. In at least one embodiment, the virtual image depth can be dynamically adjusted (Δd i ) by moving the micro display back and forth (Δa). 
     In at least one embodiment, the optical design process includes two phases: the prescription lens design (S f , S r ) and the AR display path design using an optics simulation tool such as Zemax OpticStudio. The overall optical path is difficult to investigate using an analytic form because of the free-form surface and the multiple off-axis components utilized in the display. Nevertheless, in at least one embodiment, a universal design and optimization method is demonstrated which is valid for many prescriptions including myopia, astigmatism, hyperopia, and presbyopia.  FIGS. 10-11  show an example of the two-phase optimization process in Prescription AR, which is started from the user&#39;s eyeglasses prescription including spherical correction (SPH), cylinder correction (CYL), axis of astigmatism (AXIS), and add power (ADD). 
       FIG. 6  illustrates an example of a prescription lens assembly with an image combiner, in accordance with an embodiment. In at least one embodiment, the prescription lens is constructed using two injection molded pieces. In at least one embodiment, a first lens part  602  and a second lens part  604  are joined with optical glue at an interface. In at least one embodiment, a half-silvered image combiner is placed within the interface and is embedded within the assembled lens. 
       FIG. 7  illustrates an example of prescription augmented reality for a myopic eye, in accordance with an embodiment. In at least one embodiment, the first phase is the optimization of the prescription lens, including the frontal (S f ) and rear (S r ) surface profile.  FIG. 7  shows, in one embodiment, how to design the prescription lens for a myopic eye. As shown in  FIG. 7 , the normal vision whose amplitude of accommodation is 4D has a far point at 0D and near point at 4D. The 1D myopic eye with the same amplitude of accommodation has a far point at 1D and near point at 5D. So the observer cannot perceive full-resolution images of the objects located at 0.6D. In at least one embodiment, the prescription lens shifts the object at infinity to the myopic eye&#39;s far point (1D) so that the objects are imaged at 1.6D plane, inside the depth of field (DOF). In at least one embodiment, the prescription lens compensates for astigmatism by adding inverse cylinder power to the given axis. 
     In at least one embodiment, instead of using direct calculation of surface profiles from the SPH, CYL, AXIS, and ADD values, both surfaces are determined using a human eye model. In at least one embodiment, this determination method reduces the aberration at the given thickness t l , refractive index n 3 , and given eye relief d e . Atchison built a human myopic eye model based on the measured data from 121 subjects, and it is known in the art that the total astigmatism is the sum of the corneal and internal astigmatism. However, there isn&#39;t a general human eye model covering both myopia and astigmatism. The techniques presented in the present document assume corneal astigmatism only and modified the corneal surface property of the Atchison&#39;s model. This assumption is valid in this case because the prescription lens is affected by the sum of the astigmatism, not the source. The cornea surface profile C rv  and C rh  are calculated from the CYL and AXIS value, and the modified eye model is achieved with SPH value as shown in Table 1 below. 
     In at least one embodiment, Table 1 below shows the modified myopia eye model based on Atchison&#39;s model where the r x  and r y  are the radius values of a bifocal system in horizontal and vertical respectively, k x  and k y  are the conic constant of bifocal system in horizontal and vertical respectively, N d  is the reflective index of material, and V d  is the Abbe number of the material. In at least one embodiment, the radius of cornea surface, r* x , is calculated by adding the CYL power into another direction as D x =D y +CYL, where the D y =(Nd−1)/r y . The compete equation of r x  is expressed below as Eq(1). 
     
       
         
           
               
               
               
               
               
               
               
             
               
                   
               
               
                 Surface 
                 Type 
                 Radius 
                 Conic 
                 Thickness 
                 Material 
                 Rotation 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Cornea 
                 biconic 
                 r* x  = (Nd − 1)/D x   
                 k x  = −0.15 
                 0.55 
                 Nd = 1.376 
                 90-AXIS ( ⋄ ) 
               
               
                   
                   
                 r y  = 7.77 + 0.022SR 
                 k y  = −0.15 
                   
                 Vd = 55.468 
               
               
                 Aqueous 
                 standard 
                  6.40 
                  −0.275 
                 3.05 
                 Nd = 1.3337 
                 — 
               
               
                   
                   
                   
                   
                   
                 Vd = 50.522 
               
               
                 Stop 
                 standard 
                 infinite 
                 — 
                 0.1 
                 Nd = 1.337 
                 — 
               
               
                   
                   
                   
                   
                   
                 Vd = 50.522 
               
               
                 Anterior 
                 gradient 
                 11.48 
                 −5.00 
                 1.44 
                 1.371 + 0.0652778Z 
                 — 
               
               
                 lens 
                 lens 
                   
                   
                   
                 −0.0226659Z 2   
               
               
                   
                   
                   
                   
                   
                 −0.0020399(X 2  + Y 2 ) 
               
               
                 Posterior 
                 gradient 
                 infinite 
                 — 
                 2.16 
                 1.418 − 0.0100737Z 2   
                 — 
               
               
                 lens 
                 lens 
                   
                   
                   
                 −0.0020399(X 2  + Y 2 ) 
               
               
                 Vitrous 
                 standard 
                 −5.90 
                 −2.00 
                 16.28 − 0.299SR 
                 Nd = 1.336 
                 — 
               
               
                   
                   
                   
                   
                   
                 Vd = 51.293 
               
               
                 Retina 
                 biconic 
                 r x  = −12.91 − 0.094SR 
                 k x  = 0.7 + 0.026SR 
                 — 
                 — 
                 — 
               
               
                   
                   
                 r y  = −12.72 + 0.004SR 
                 k y  = 0.225 + 0.017SR 
               
               
                   
               
            
           
         
       
     
     In at least one embodiment, based at least in part on this modified myopia eye model, S f  and S r  are determined. In at least one embodiment, S f  is set as a spherical surface of radius r f  while S r  is set as a bifocal surface of radii r ro , r re  and rotation angle θ r , to correct the myopia and the astigmatism. In an embodiment, the values were optimized iteratively with the merit function for the range of 12 to 20 mm eye relief and 26×18 degrees of the field. 
     In at least one embodiment,  FIG. 8  shows a spot diagram change around the retina plane of a myopic astigmatism eye (SPH: −2, CYL: −2, and AXIS: 30) without and with the prescription lens. In at least one embodiment, compared to the naked eye and the myopia-only correction lens, the designed prescription lens forms a smaller focal point at the retinal plane as shown in  FIG. 8 . In at least one embodiment,  FIG. 8  illustrates a spot diagram on the retina through focus shifting: (a) the blurred spot on the retina from the infinite object without prescription lens, (b) the focused spot on the retina only optimized for SPH, and (c) optimized for SPH, CYL, and AXIS. 
     
       
         
           
             
               
                 
                   
                     r 
                     x 
                     * 
                   
                   = 
                   
                     
                       
                         r 
                         y 
                       
                       × 
                       
                         ( 
                         
                           Nd 
                           - 
                           1 
                         
                         ) 
                       
                     
                     
                       
                         ( 
                         
                           Nd 
                           - 
                           1 
                         
                         ) 
                       
                       + 
                       
                         CYL 
                         × 
                         
                           r 
                           y 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     In at least one embodiment, based at least in part on the prescription lens design, other geometric parameters (R l1 , R l2 , R cy , a, d p , t BSL , t c , t w , θ d , θ l , θ p , θ c , θ w , θ free , and S free ) are optimized in the second phase. In at least one embodiment, although actual numbers will be calculated by a tool such as Zemax OpticStudio, the geometry of optics, the materials, the constraints, and the priority (merit function) should be carefully considered at the design stage for the best performance. 
     In at least one embodiment,  FIG. 5  shows a detailed diagram of the AR display path. In at least one embodiment, in the waveguide, the light rays are reflected at the positive power surface (S f ) first, and at the negative power surface (S r ) second. In at least one embodiment, it is reasonable to choose a positive power image combiner (S free ) for the freeform surface to produce a flatter focal plane, symmetric power distribution, and less aberration. In at least one embodiment, the freeform surface is characterized by an extended polynomial equation including conic aspherical surfaces and extended polynomial terms as follows: 
     
       
         
           
             
               
                 
                   
                     z 
                     = 
                     
                       
                         
                           cr 
                           2 
                         
                         
                           1 
                           + 
                           
                             
                               1 
                               - 
                               
                                 ( 
                                 
                                   
                                     ( 
                                     
                                       1 
                                       + 
                                       k 
                                     
                                     ) 
                                   
                                    
                                   
                                     c 
                                     2 
                                   
                                    
                                   
                                     r 
                                     2 
                                   
                                 
                                 ) 
                               
                             
                           
                         
                       
                       + 
                       
                         
                           ∑ 
                           i 
                           N 
                         
                          
                         
                           
                             A 
                             i 
                           
                            
                           
                             
                               E 
                               i 
                             
                              
                             
                               ( 
                               
                                 x 
                                 , 
                                 y 
                               
                               ) 
                             
                           
                         
                       
                     
                   
                   , 
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
     
     where c is the curvature for the base sphere, r is the normal radius expressed as r=√{square root over (x 2 )}+y 2 , k is the conic constant, N is the number of polynomial terms, and A i  is the coefficient of the i th  extended polynomial terms as Eq(3). In at least one embodiment, as part of the optimization in freeform surface, the 4 th  polynomial has been considered, in which N=16 in the Eq(3) below. 
       Σ i=0   N   A   i   E   i ( x,y )= A   0   +A   1   x   1   y   0   +A   1   x   0   y   1   +A   3   x   2   y   0   +A   4   x   1   y   1   +A   5   x   0   y   2 + . . .   (3)
 
     In at least one embodiment, the bi-convex beam-shaping lens increases the system&#39;s numerical aperture (NA) for higher resolution and compactness (shorter optical path). In at least one embodiment, the in-coupling prism guides the light rays into the waveguide with the total internal reflection condition. In at least one embodiment, the y-axis only cylindrical surface (R cy ) inside the in-coupling prism compensates the astigmatism and the tilted image plane, which are caused by the off-axis folded path. In at least one embodiment, the tilted angle of the beam-shaping lens is identical to the tilted angle of the micro-display for the symmetric magnification (θ d =θ t ), but the angles of other components were freely decided by the optimizer to maximize FOV and minimize aberration. In at least one embodiment, the materials for the beam shaping lens and the upper part of the in-coupling prism (n 1 , v 1 ), the lower part of that (n 2 , v 2 ), and the prescription lens (n 3 , v 3 ), where n and v refer to index of refraction and Abbe number respectively, were carefully chosen to minimize the thicknesses and the chromatic aberration using the different dispersion characteristics. In at least one embodiment, the distances (a, d p , t BSL , t c , t w ) were calculated to some non-negative values based on various constraints and the priorities. 
     In at least one embodiment, the optical configuration for AR function is limited by giving the constraints for the optical system in the Merit function. In at least one embodiment, the constraints are determined by the comprehensive consideration of lens implementation, distance from forehead, total internal reflection (TIR) inside prescription lens, and boundary on display panel. In at least one embodiment, the center thickness and edge thickness of each lens, t BSL , t c , t w , are limited to more than one mm for the manufacturability of the lens. In at least one embodiment, constraints for the air thickness, a, dp, are limited to more than 0.2 mm to avoid the superposition of the lens. In at least one embodiment, the sum of thickness a, d p , t BSL , t c , and t w  are limited to within 8.5 mm to minimize total thickness of AR system. 
       FIGS. 10-11  illustrate an embodiment of the two-phase optimization of a prescription AR display. In at least one embodiment, the frontal and rear surfaces (S f , S r ) are optimized at given lens thickness t l  in the first step based on user&#39;s prescription. In at least one embodiment, other geometric parameters (R l1 , R l2 , R cy , a, d p , t BSL , tc, t w , θ d , θ l , θ p , θ c , θ w , and θ free ) are optimized in the second step based on target foveated resolution and eye relief range d e . 
       FIG. 10  illustrates an example of a process  1000  that, as a result of being performed, optimizes a prescription lens of a prescription AR display, in accordance with an embodiment. In at least one embodiment, at block  1002 , a prescription is obtained for a wearer. The prescription may be, in various embodiments, a prescription for myopia, astigmatism, presbyopia, or various combinations of vision problems. In at least one embodiment, at block  1004 , a mathematical model for the eye is generated in accordance with the obtained prescription. In the present document, an example for a myopic eye is presented. In at least one embodiment, at block  1006 , a script for Zemax Studio macro as described below is executed with appropriate vision correction parameters. In at least one embodiment, at block  1008 , the bifocal power and rotation angle of the z-axis in the cornea surface are determined. In at least one embodiment, at block  1010 , the prescription lens surface is initialized, and at block  1012 , the Merit function criterion is set. In at least one embodiment, at block  1014 , the bifocal radius and rotated angle of the prescription lens surface is optimized, and at block  1016 , optimization of the prescription portion of the AR display is complete. 
       FIG. 11  illustrates an example of a process  1100  that, as a result of being performed, optimizes an AR display of a prescription AR display, in accordance with an embodiment. In at least one embodiment, at block  1102 , the prescription lens parameters determined above are obtained. In at least one embodiment, at block  1104 , the relationship between the image combiner and the display panel is modeled. In at least one embodiment, the relationship establishes a foveated image that is presented to the wearer. In at least one embodiment, at block  1106 , the parameters defining the AR display, including the image combiner, are determined. In at least one embodiment, at block  1108 , the constant of the merit function is established. In at least one embodiment, at block  1110 , the resolution distribution of the foveated display is set. In at least one embodiment, the resolution of the foveated display is achieved as a result of the electronic micro-display being flat, and the optics of the beam shaping lens and optical path correcting the shape of the display to match the image combiner. In at least one embodiment, the resolution density presented to the wearer is illustrated in  FIG. 9 . In at least one embodiment, at block  1112 , the polynomial coefficient surface performance of the surface is optimized. In at least one embodiment, at block  1114 , due to the adjustment of the foveated display, a center resolution of over 23 cycles per degree (“CPR”) is achieved. In at least one embodiment, at block  1116 , the AR display optimization is complete. 
     In at least one embodiment, where the thickness of the prescription lens is 5 mm, the size of the free-form combiner is limited, especially in the vertical field of view. In at least one embodiment, the thicker prescription lens allows a larger field of view by the larger size of the combiner. In at least one embodiment, although it is complicated to evaluate the FoV from the free-form surface and reflection constraint of the light path, tools such as Zemax Studio provide an effective way to get the vertical field of view. As shown in  FIGS. 12-14 , the trend line is linear to the thickness of the prescription lens. In at least one embodiment, the eye box size grows with lens thickness. 
       FIGS. 12-14  illustrate an embodiment of a design trade-off space for the prescription AR display. In at least one embodiment, the micro display w d ×h d =10.08×7.56 mm and pixel pitch 6.3 μm, virtual image plane d i =1D, and thickness t l =5 mm.  FIG. 12  illustrates thickness vs. FOV and eye box. In at least one embodiment, both FOV and eye box are proportional to the t l .  FIG. 13  illustrates focus cue. In at least one embodiment, the virtual image plane can be changed back and forth (Δd) with the axial movement of the micro display (Δa).  FIG. 14  illustrates Eye Relief vs. FOV. In at least one embodiment, smaller eye relief provides larger FOV 
       FIG. 9  illustrates an example of the angular resolution of a foveated AR display as viewed by the wearer, in accordance with an embodiment. In at least one embodiment, the AR display is a fixed foveated display. In at least one embodiment, the AR display is adjusted to the foveated resolution distribution, which presents a high angular resolution, 26 CPR, at the foveal region and a low angular resolution, 3 cpd, outside of foveated region in optics. In at least one embodiment, the panel used is a 6.3 μm micro-OLED, which can reach to 23 CPR of angular resolution. In at least one embodiment, an optimization is performed done in Zemax Studio by giving the foveated weight of optimized priority order for the field. In at least one embodiment, the special frequency date of MTF30 is extracted from Zemax Studio and the data is converted into angular resolution by calculating the field of view of the AR image, as shown in  FIG. 9 . In at least one embodiment, the high-resolution region is not symmetric because it is hard to perfectly compensate the AXIS angle of astigmatism.  FIG. 9  illustrates foveated optimization of angular resolution over FOV for a 1D myopia prescription AR display. 
     In at least one embodiment, using the techniques described herein, a person of ordinary skill in the art is able to adjust the prescription AR display to correct for most vision problems including myopia, astigmatism, presbyopia, and various combinations these problems. In various embodiments, the prescription AR is adaptable to multiple myopia cases (0D (normal vision), 1D, 2D, 3D, 4D, and 5D) and a myopic astigmatism case (SPH=2D, CYL=2, AXIS=30). Table 2 shows design parameters for one embodiment of a 1D myopia Prescription AR display. Table 2 shows the geometric and optical parameters of one embodiment of prescription AR for 1D myopia. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 The designed performance of implemented 
               
               
                 prescription embedded AR display. 
               
            
           
           
               
               
               
               
            
               
                   
                 Items 
                 Units 
                 Values 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Prescription 
                 diopther 
                 −1 
               
               
                   
                 Lens thickness 
                 mm 
                 5 
               
               
                   
                 Eye relief 
                 mm 
                 20 
               
               
                   
                 Eye box 
                 mm 
                 4 
               
               
                   
                 Image object 
                 m, through the lens 
                 1 
               
               
                   
                 Field of view 
                 degrees 
                 20 × 40 
               
               
                   
                 Resolution 
                 cycles per degree(CPR) 
                 23 at center 
               
               
                   
                   
               
            
           
         
       
     
     In at least one embodiment, the fabrication of the optical components may be accomplished with the following techniques. In at least one embodiment, since facial structure is unique to the wearer, the ergonomic frame design is as important as the optics design. In at least one embodiment, the optics for the eye relief of the AR display is optimized in the range of 12 mm to 20 mm. In at least one embodiment, however, smaller eye relief can provide a larger FOV and a more comfortable fit (closer center of mass). In at least one embodiment, the center of the pupil should be aligned with the optical axis for a superior foveated experience. In at least one embodiment, frame design of the glasses should be chosen in accordance with the wearer&#39;s interpupillary distance (“IPD”) too. 
     In at least one embodiment, the facial structure of the intended wearer as illustrated in  FIG. 1  is 3D-scanned with a 3D-Camera such as the Kinect sensor from Microsoft, and imported to 3D-rendering software (such as Fusion  360 ), and the glasses frame is designed and optimized for each user. In at least one embodiment, the glasses frame designs are parameterized with the input of the IPD and the width of the head, followed by fitting if the nose pieces. 
     In at least one embodiment, an OLED-based dynamic prototype was created with the following features. In at least one embodiment, two 10.08×7.56 mm Sony micro OLED (ECX339A) displays were used as binocular micro displays, where each display has 1600×1200 resolution, 6.3 μm pixel pitch, and maximum brightness 1000 cd/m2. In at least one embodiment, the free-form optics with the 70% transparency for 1D myopia were fabricated. In at least one embodiment, a 3D-printed frame housed and aligned the optical structures including main lens+in-coupling prism, beam-shaping lens, micro display, and driving board. In at least one embodiment, a 3D printed gear was also applied to change the IPD. In at least one embodiment, the weight of the dynamic prototype including the driving board was 164 g. 
     In at least one embodiment, an LUT-based static prototype was created with the following features. In at least one embodiment, two sets of a 10.08×7.56 mm, 3048 pixel per inch light valve technology (LUT) film with an ElectroLuminescent (EL) film back light were used for the static display. In at least one embodiment, a CR-2032 coin cell powered both EL films. In at least one embodiment, a 3D-printed housing aligned all of the optics, statics display modules, and the battery for wearable eye glasses form factor. In at least one embodiment, the weight of the static prototype was 79 g. 
     In at least one embodiment, the image content for the prototype is a binocular image. In at least one embodiment, the binocular image is produced by a G3D Innovation Engine which is a powerful rendering engine with the open source of C++ program. In at least one embodiment, the rendering engine supports the image rendering of virtual reality that allows the customer to add the scene by a virtual reality platform such as VRapp. In at least one embodiment, in the coding of the virtual reality platform, the field of view, depth of focus, pupillary distance, and resolution are set with same parameter of the prescription-embedded AR display. In at least one embodiment, the field of view measurement of the AR image covered 20 by 40 degrees in the vertical and horizontal direction respectively. 
     In at least one embodiment, the AR display achieves corrected vision. In an experiment conduced on a prototype of an embodiment, a scene for different real objects including a car, a horse, and an eye chart with a distance of 0.5 m, 1 m, and 3 m respectively, was used. In at least one embodiment, in order to imitate a wearer who has a 1 diopter myopia eye, the camera focused on the car in the scene without the prescription-embedded AR display. The clear details on the car show that a 1 diopter myopia eye is able to clearly view an object at 0.5 m. In at least one embodiment, using the prescription-embedded AR display, the focus point shifted to 1 m to target the horse, without changing the setting of focus on the camera. The focus shift amount demonstrates that the prescription lens has −1 diopter power. In at least one embodiment, a clear AR image is presented by the display panel at 1 m distance through the prescription embedded AR display, and the eye chart looks sharper due to the contribution of vision correction. 
       FIG. 15  illustrates an example of an AR display with an adjustable image position, in accordance with an embodiment. In at least one embodiment, the AR display can be adapted to operate as a vari-focal AR display. As shown in  FIG. 15 , a three-position Micro-OLED (“MOLED”) panel  1502  with size, Pd, and shifting distance, δd, makes the different depth of AR image at d1, d2, and d3 from the eye, where equal to 0.5 m, 1 m, and 3 m, respectively. In at least one embodiment, three kinds of thickness of assemblies for Micro-OLED panel provide the shifting amount of 0.3 mm, δd. In at least one embodiment, the depth of the clear AR image is controlled and produces a vari-focal display that reduces the problem of vergence and accommodation conflict (VAC) in the near-eye display system. 
     In at least one embodiment, a vision correction function is an important property in a near-eye display system. In at least one embodiment, an AR display is directly integrated into a prescription lens. In at least one embodiment, each individual AR display is adapted to include a customized prescription lens in accordance with a prescription of SPH, CYL, and AXIS. In at least one embodiment, the configuration of the optical components can be used for the myopia patient with 0 to −7 diopter, −2 diopter of astigmatism, and rotation angle of astigmatism. 
     In at least one embodiment, a free-form image combiner is made by molding a prescription lens in two pieces and coating the interface between the two pieces with anti-reflective coating and 30% of ND filter coating. In at least one embodiment, the system achieves a field of view of 20 by 40 degrees and a foveated resolution distribution of 23 CPR in the foveal region. In at least one embodiment, the eye box size is 4 mm. In at least one embodiment, the prescription-embedded AR display described herein offers both corrected vision and a clear AR image at 1 m. In at least one embodiment, the depth of the AR image is adjustable from 0.5 m to 3 m by applying a corresponding 0.3 mm shift to the position of the display panel. 
     In at least one embodiment, the prescription embedded AR display is a compact design, which provides a volume of 6.5 cm3 for the optical engine, including the 5 mm thickness prescription lens, other optical elements, and a micro-OLED. In at least one embodiment, the prescription embedded AR display achieves vision correction for the environment scene and also gives a clear AR image for the wearer. 
       FIG. 16  illustrates an example of the angular resolution of a foveated display, in accordance with an embodiment. The graph illustrates an embodiment where the perceived resolution of AR content is higher toward the center of the field of view and lower toward the edges of the field of view. 
       FIG. 17  illustrates an example of a modular augmented reality display with an upward configuration that allows the separate use a prescription eyeglass component, in accordance with an embodiment. In at least one embodiment, the augmented reality display is produced in an eyeglass form factor having a frame with two arms  1702  and  1704 . In at least one embodiment, a power and control unit  1706  drives a pair of electronic displays  1716  and  1718  removably mounted to the top of the frame. In at least one embodiment, the power and control unit  1706  includes one or more buttons to allow control of the display by the wearer. In at least one embodiment, the power and control unit  1706  is connected to a remote support pack worn by the user that includes a battery, microcomputer, and wireless interface. In at least one embodiment, the microcomputer may include a CPU or GPU as described in  FIGS. 22 through 26 . In at least one embodiment, the augmented reality display includes two lenses  1708  and  1710  that include an image combiner within each lens. In at least one embodiment, the image combiner combines the image transmitted through the lens with the image created by the electronic display. In at least one embodiment, the augmented reality display includes a beam-shaping lens and prism ( 1712  and  1714 ) in each lens that directs the image produced by the electronic display downward into the lens such that the image is internally reflected and directed to the image combiner of each lens. 
     In at least one embodiment, the AR display includes connectors  1724  and  1726  that allow the removal and attachment of the electronic displays  1716  and  1718 . In at least one embodiment, the connectors  1724  and  1726  are magnetic attachments. In at least one embodiment, the magnetic attachments include conductors that transmit electrical signals to and from the control unit and/or the support pack. In at least one embodiment, the connectors are a clip, clasp, or slot that retain the electronic displays  1716  and  1718 . In at least one embodiment, the connectors  1724  and  1726  include indexing features or keyways that aid in aligning the electronic displays  1716  and  1718  with the lenses  1708  and  1710 . In at least one embodiment, the eyeglasses include mechanical alignment features to aid in attaching the display to the AR display to the eyeglasses. In at least one embodiment, mechanical alignment is achieved using a mortise and tenon, one or more groves and ridges, or pins and matching holes. In at least one embodiment, the electronic displays  1716  and  1718  include an organic light emitting diode (“OLED”) display element coupled to one or more lenses and or prisms to direct and shape an image. 
     In at least one embodiment, a pair of driving boards  1720  and  1722  are attached to the electronic displays  1716  and  1718 . In at least one embodiment, each driving board includes interface circuits and driving circuits for an OLED display. In at least one embodiment, the pair of driving boards  1720  and  1722  project upwards above the lenses. In at least one embodiment, the driving boards connect to the electronic displays  1716  and  1718  via edge connectors. 
     In at least one embodiment, the control unit  1706  includes a battery, microcomputer, and interface for communicating with a server computer system. In at least one embodiment, the interface is a wireless Bluetooth or WiFi interface. In at least one embodiment, the control unit  1706  relays display information from the server computer system to the pair of driving boards  1720  and  1722 . In at least one embodiment, the control unit  1706  is removable in addition to other AR components to reduce the weight of the eyewear when AR features are not needed. 
       FIG. 18  illustrates an example of a modular augmented reality display with an outward configuration that allows the separate use of prescription eyeglass component, in accordance with an embodiment. In at least one embodiment, the augmented reality display is produced in an eyeglass form factor having a frame with two arms  1802  and  1804 . In at least one embodiment, a power and control unit  1806  drives a pair of electronic displays  1816  and  1818  removably mounted to the top of the frame. In at least one embodiment, the power and control unit  1806  includes one or more buttons to allow control of the display by the wearer. In at least one embodiment, the power and c is connected to a remote support pack worn by the user that includes a battery, microcomputer, and wireless interface. In at least one embodiment, the microcomputer may include a CPU or GPU as described in  FIGS. 22 through 26 . In at least one embodiment, the augmented reality display includes two lenses  1808  and  1810  that include an image combiner within each lens. In at least one embodiment, the image combiner combines the image transmitted through the lens with the image created by the electronic display. In at least one embodiment, the augmented reality display includes a beam-shaping lens and prism ( 1812  and  1814 ) in each lens that directs the image produced by the electronic display downward into the lens such that the image is internally reflected and directed to the image combiner of each lens. 
     In at least one embodiment, the AR display includes connectors  1824  and  1826  that allow the removal and attachment of the electronic displays  1816  and  1818 . In at least one embodiment, the connectors  1824  and  1826  are magnetic attachments. In at least one embodiment, the magnetic attachments include conductors that transmit electrical signals to and from the control unit and/or the support pack. In at least one embodiment, the connectors are a clip, clasp, or slot that retain the electronic displays  1816  and  1818 . In at least one embodiment, the connectors  1824  and  1826  include indexing features or keyways that aid in aligning the electronic displays  1816  and  1818  with the lenses  1808  and  1810 . In at least one embodiment, the electronic displays  1816  and  1818  include an organic light emitting diode (“OLED”) display element coupled to one or more lenses and or prisms to direct and shape an image. 
     In at least one embodiment, a driving board  1820  is attached to the electronic displays  1816  and  1818 . In at least one embodiment, each driving board includes interface circuits and driving circuits for an OLED display. In at least one embodiment, the driving board  1820  projects outwards from the lenses. In at least one embodiment, the driving board  1820  connects to the electronic displays  1816  and  1818  via edge connectors. In at least one embodiment, the driving board  1820  is connected via a hinged connector allowing the board to pivot on an axis along the top of the eyeglasses. By allowing the driving board  1820  to pivot up and down, the position of the driving board  1820  can be adjusted to allow for the user wearing a hat with the AR display. 
     In at least one embodiment, the control unit  1806  is integrated into the support pack, and display signals are transmitted from the control pack to the driving board  1820  and the electronic displays  1816  and  1818 . In at least one embodiment, the support pack includes user interface buttons that control the operation of the AR display. 
       FIG. 19  illustrates an example of a detachable display assembly  1916  of an augmented reality display, in accordance with an embodiment. In at least one embodiment, the augmented reality display includes a free-form image combiner  1902  embedded within a prescription lens  1904 . In at least one embodiment, the prescription lens  1904  is fabricated in accordance with a vision correction prescription. In at least one embodiment, the free-form image combiner  1902  is made by coating the interface between two parts of the prescription lens  1904  with a half-silver material and joining the parts with optical glue. In at least one embodiment, the lens assembly includes an in-coupling prism  1906 . 
     In at least one embodiment, the detachable display assembly  1916  includes a beam-shaping lens  1908  that directs an image produced by a micro LED  1912  into the edge of the prescription lens  1904 . In at least one embodiment, the beam-shaping lens  408  is retained in position by a lens holder  1910  removably attached to a frame of the augmented reality display. In at least one embodiment, the detachable display assembly  1916  is attached to the prescription lens  1904  with a magnetic attachment or mechanical clip. In at least one embodiment, the micro-LED is held in pace with a panel holder  1914 . In at least one embodiment, the panel holder  1914  includes a manual or electronic actuator that allows the micro-LED to be moved along the optical axis of the beam-shaping lens. In at least one embodiment, movement of the micro-LED panel is accomplished with a thumbscrew attached to the threaded rod. In at least one embodiment, movement of the micro LED panel is accomplished using an ultra-thin auto focus actuator module (“UTAF”). 
       FIG. 20  illustrates an example of a modular augmented reality display being worn by a user, in accordance with an embodiment. In at least one embodiment, a user  2000  is wearing an AR display  2002  that integrated with a set of prescription eyewear. In at least one embodiment, the user  2000  wears a support pack  2004  which is connected to the AR display  2002  via an electrical cable  2006 . In at least one embodiment, the support pack  2004  includes a battery, microcomputer, and wireless interface capable of communicating with a server that provides display information. In at least one embodiment, the wireless interface is an 802.11 or WiFi interface. In at least one embodiment, the wireless interface is a Bluetooth interface. In at least one embodiment, the electrical cable  2006  is replaced or augmented by a Bluetooth or near-field wireless connection between the support pack  2004  and the AR display  2002 . 
     In at least one embodiment, by moving various components to the support pack  2004 , the weight of the remaining components which are worn on the users&#39; head are approximately 50-100 grams. In at least one embodiment, the weight of the prescription eyewear only, without AR-related components is less than 50 grams. It has been suggested that people that wear prescription eyewear generally must do so for about 16 hours per day, and that in this extended use, a weight of more than 50 g becomes uncomfortable for many users. By moving heavy components such as the battery to the support pack  2004 , the AR headset can be comfortably used for many hours. If AR features are not needed, in some embodiments, the display drivers and OLED displays may be detached from the eyewear reducing the weight of the eyewear even more. 
       FIG. 21  illustrates an example of a modular augmented reality display that communicates with a computer server, in accordance with an embodiment. In at least one embodiment, a user  2102  wears an AR display that includes a pair of arms  2106  and a prescription lens  2104 , such as a prescription AR display described above. In at least one embodiment, the AR display includes a micro organic light emitting diode (“MOLED”) display  2108  and a display interface  2110  coupled to the display  2108 . In at least one example, the display  2108  may be an LED, AMOLED, or LCD display. In at least one embodiment, the display interface  2110  and MOLED display  2109  are removable by the user  2102 , so that the prescription AR display can be used as a set of prescription eyewear without AR functionality. In at least one embodiment, the resulting eyewear is lightened, increasing comfort for the user  2102 . 
     In various examples the display interface  2110  includes an electrical interface that communicates with a support pack  2114  via a cable  2112 . In at least one embodiment, the display interface includes electronic video display driver circuitry that converts signals obtained from the support pack  2114  into image data that is provided to the display  2108 . In at least one embodiment, the display  2108  converts the image data into images that are displayed to the user  2102  via the prescription lens  2104  as described above. 
     In at least one embodiment, the support pack  2114  includes a wireless interface  2116 , a battery  2120 , and a microcomputer  2118 . In at least one embodiment, the microcomputer  2118  may be a computer system having one or more processors and memory containing instructions that, as a result of being executed by the one or more processors, case the microcomputer  2118  to acquire information from a computer server  2124 , process the information, and send display information to the display interface  2110 . In at least one embodiment, the battery  2120  is a lithium ion, NiCad, Alkaline or other battery that provides power to the support pack. In some examples, the battery  2120  supplies power to the display interface  2110  and display  2108  via the cable  2112 . In some examples, the cable  2112  supplies both serial data and power to the display interface  2110  over a single wire of the cable  2112 . 
     In at least one embodiment, the support pack  2114  communicates with the computer server  2124  using the wireless interface  2116 . In at least one embodiment, the wireless interface is a WiFi, cellular, or Bluetooth interface. In at least one embodiment, the computer server  2124  provides display information to the AR display via the support pack  2114 . The support pack lightens the weight on the user&#39;s  2102  head when AR images are being used. By providing a wireless connection between the support pack  2114  and the computer server  2124 , freedom of movement is provided to the user  2102  while using the AR display. 
       FIGS. 22-26  illustrate various systems that can be used to implement various embodiments of the invention. The systems illustrated and discussed in connection with  FIGS. 22-26  may be used, for example, to execute instructions to perform algorithms discussed herein including but not limited to image processing (e.g., object detection, object recognition, image segmentation, and other techniques) and calculating display information (e.g., the display to be rendered and/or a portion thereof, such as content to be added to an image captured through one or more cameras). Software to implement the various techniques described herein can be executed using one or more of the systems discussed below and illustrated in connection with  FIGS. 22-26 . 
     In at least one embodiment, the AR display includes an electronic display such as an organic light emitting diode (“OLED”), light emitting diode (“LED”), light valve technology (“LUT”) display, or liquid crystal display (“LCD”). In at least one embodiment, the electronic display produces an image which is directed through a beam-shaping lens and in-coupling prism into the edge of the lens of the AR display. In at least one embodiment, the image is internally reflected within the lens by the surfaces of the lens until the image encounters a free-form image combiner located internally to the lens. In at least one embodiment, the surface profile of the image combiner is constructed as described herein so that both the image transmitted through the lens, and the image generated by the AR display are presented to a wearer in accordance with a vision prescription for corrective eyewear. 
     In at least one embodiment, a computer system with one or more processors is coupled to the electronic display, and the computer system includes memory and instructions that, when executed, cause the computer system to generate electrical signals that are transmitted to the electronic display. In at least one embodiment, the electrical signals are converted by the electrical display into an image. In at least one embodiment, an augmented reality graphics framework such as Spark AR, Wikitude, ARKit or ARCore on the computer system allows an application developer to create software, that when run on the computer system, directs the addition of augmented reality elements on the AR display. 
       FIG. 22  illustrates a parallel processing unit (“PPU”)  2200 , in accordance with one embodiment. In an embodiment, the PPU  2200  is configured with machine-readable code that, if executed by the PPU, causes the PPU to perform some or all of the processes and techniques described throughout this disclosure. In an embodiment, the PPU  2200  is a multi-threaded processor that is implemented on one or more integrated circuit devices and that utilizes multithreading as a latency-hiding technique designed to process computer-readable instructions (also referred to as machine-readable instructions or simply instructions) on multiple threads in parallel. In an embodiment, a thread refers to a thread of execution and is an instantiation of a set of instructions configured to be executed by the PPU  2200 . In an embodiment, the PPU  2200  is a graphics processing unit (“GPU”) configured to implement a graphics rendering pipeline for processing three-dimensional (“3D”) graphics data in order to generate two-dimensional (“2D”) image data for display on a display device such as a liquid crystal display (LCD) device. In an embodiment, the PPU  2200  is utilized to perform computations such as linear algebra operations and machine-learning operations.  FIG. 22  illustrates an example parallel processor for illustrative purposes only and should be construed as a non-limiting example of processor architectures contemplated within the scope of this disclosure and that any suitable processor may be employed to supplement and/or substitute for the same. 
     In an embodiment, one or more PPUs are configured to accelerate High Performance Computing (“HPC”), data center, and machine learning applications. In an embodiment, the PPU  2200  is configured to accelerate deep learning systems and applications including the following non-limiting examples: autonomous vehicle platforms, deep learning, high-accuracy speech, image, text recognition systems, intelligent video analytics, molecular simulations, drug discovery, disease diagnosis, weather forecasting, big data analytics, astronomy, molecular dynamics simulation, financial modeling, robotics, factory automation, real-time language translation, online search optimizations, and personalized user recommendations, and more. 
     In an embodiment, the PPU  2200  includes an Input/Output (“I/O”) unit  2206 , a front-end unit  2210 , a scheduler unit  2212 , a work distribution unit  2214 , a hub  2216 , a crossbar (“Xbar”)  2220 , one or more general processing clusters (“GPCs”)  2218 , and one or more partition units  2222 . In an embodiment, the PPU  2200  is connected to a host processor or other PPUs  2200  via one or more high-speed GPU interconnects  2208 . In an embodiment, the PPU  2200  is connected to a host processor or other peripheral devices via an interconnect  2202 . In an embodiment, the PPU  2200  is connected to a local memory comprising one or more memory devices  2204 . In an embodiment, the local memory comprises one or more dynamic random access memory (“DRAM”) devices. In an embodiment, the one or more DRAM devices are configured and/or configurable as high-bandwidth memory (“HBM”) subsystems, with multiple DRAM dies stacked within each device. 
     The high-speed GPU interconnect  2208  may refer to a wire-based multi-lane communications link that is used by systems to scale and include one or more PPUs  2200  combined with one or more CPUs, supports cache coherence between the PPUs  2200  and CPUs, and CPU mastering. In an embodiment, data and/or commands are transmitted by the high-speed GPU interconnect  2208  through the hub  2216  to/from other units of the PPU  2200  such as one or more copy engines, video encoders, video decoders, power management units, and other components which may not be explicitly illustrated in  FIG. 22 . 
     In an embodiment, the I/O unit  2206  is configured to transmit and receive communications (e.g., commands, data) from a host processor (not illustrated in  FIG. 22 ) over the interconnect  2202 . In an embodiment, the I/O unit  2206  communicates with the host processor directly via the interconnect  2202  or through one or more intermediate devices such as a memory bridge. In an embodiment, the I/O unit  2206  may communicate with one or more other processors, such as one or more of the PPUs  2200  via the interconnect  2202 . In an embodiment, the I/O unit  2206  implements a Peripheral Component Interconnect Express (“PCIe”) interface for communications over a PCIe bus. In an embodiment, the I/O unit  2206  implements interfaces for communicating with external devices. 
     In an embodiment, the I/O unit  2206  decodes packets received via the interconnect  2202 . In an embodiment, at least some packets represent commands configured to cause the PPU  2200  to perform various operations. In an embodiment, the I/O unit  2206  transmits the decoded commands to various other units of the PPU  2200  as specified by the commands. In an embodiment, commands are transmitted to the front-end unit  2210  and/or transmitted to the hub  2216  or other units of the PPU  2200  such as one or more copy engines, a video encoder, a video decoder, a power management unit, etc. (not explicitly illustrated in  FIG. 22 ). In an embodiment, the I/O unit  2206  is configured to route communications between and among the various logical units of the PPU  2200 . 
     In an embodiment, a program executed by the host processor encodes a command stream in a buffer that provides workloads to the PPU  2200  for processing. In an embodiment, a workload comprises instructions and data to be processed by those instructions. In an embodiment, the buffer is a region in a memory that is accessible (e.g., read/write) by both the host processor and the PPU  2200 —the host interface unit may be configured to access the buffer in a system memory connected to the interconnect  2202  via memory requests transmitted over the interconnect  2202  by the I/O unit  2206 . In an embodiment, the host processor writes the command stream to the buffer and then transmits a pointer to the start of the command stream to the PPU  2200  such that the front-end unit  2210  receives pointers to one or more command streams and manages the one or more streams, reading commands from the streams and forwarding commands to the various units of the PPU  2200 . 
     In an embodiment, the front-end unit  2210  is coupled to a scheduler unit  2212  that configures the various GPCs  2218  to process tasks defined by the one or more streams. In an embodiment, the scheduler unit  2212  is configured to track state information related to the various tasks managed by the scheduler unit  2212  where the state information may indicate which GPC  2218  a task is assigned to, whether the task is active or inactive, a priority level associated with the task, and so forth. In an embodiment, the scheduler unit  2212  manages the execution of a plurality of tasks on the one or more GPCs  2218 . 
     In an embodiment, the scheduler unit  2212  is coupled to a work distribution unit  2214  that is configured to dispatch tasks for execution on the GPCs  2218 . In an embodiment, the work distribution unit  2214  tracks a number of scheduled tasks received from the scheduler unit  2212  and the work distribution unit  2214  manages a pending task pool and an active task pool for each of the GPCs  2218 . In an embodiment, the pending task pool comprises a number of slots (e.g., 32 slots) that contain tasks assigned to be processed by a particular GPC  2218 ; the active task pool may comprise a number of slots (e.g., 4 slots) for tasks that are actively being processed by the GPCs  2218  such that as a GPC  2218  completes the execution of a task, that task is evicted from the active task pool for the GPC  2218  and one of the other tasks from the pending task pool is selected and scheduled for execution on the GPC  2218 . In an embodiment, if an active task is idle on the GPC  2218 , such as while waiting for a data dependency to be resolved, then the active task is evicted from the GPC  2218  and returned to the pending task pool while another task in the pending task pool is selected and scheduled for execution on the GPC  2218 . 
     In an embodiment, the work distribution unit  2214  communicates with the one or more GPCs  2218  via XBar  2220 . In an embodiment, the XBar  2220  is an interconnect network that couples many of the units of the PPU  2200  to other units of the PPU  2200  and can be configured to couple the work distribution unit  2214  to a particular GPC  2218 . Although not shown explicitly, one or more other units of the PPU  2200  may also be connected to the XBar  2220  via the hub  2216 . 
     The tasks are managed by the scheduler unit  2212  and dispatched to a GPC  2218  by the work distribution unit  2214 . The GPC  2218  is configured to process the task and generate results. The results may be consumed by other tasks within the GPC  2218 , routed to a different GPC  2218  via the XBar  2220 , or stored in the memory  2204 . The results can be written to the memory  2204  via the partition units  2222 , which implement a memory interface for reading and writing data to/from the memory  2204 . The results can be transmitted to another PPU or CPU via the high-speed GPU interconnect  2208 . In an embodiment, the PPU  2200  includes a number U of partition units  2222  that is equal to the number of separate and distinct memory devices  2204  coupled to the PPU  2200 . A partition unit  2222  will be described in more detail below. 
     In an embodiment, a host processor executes a driver kernel that implements an application programming interface (“API”) that enables one or more applications executing on the host processor to schedule operations for execution on the PPU  2200 . In an embodiment, multiple compute applications are simultaneously executed by the PPU  2200  and the PPU  2200  provides isolation, quality of service (“QoS”), and independent address spaces for the multiple compute applications. In an embodiment, an application generates instructions (e.g., in the form of API calls) that cause the driver kernel to generate one or more tasks for execution by the PPU  2200 , and the driver kernel outputs tasks to one or more streams being processed by the PPU  2200 . In an embodiment, each task comprises one or more groups of related threads, which may be referred to as a warp. In an embodiment, a warp comprises a plurality of related threads (e.g., 32 threads) that can be executed in parallel. In an embodiment, cooperating threads can refer to a plurality of threads including instructions to perform the task and that exchange data through shared memory. Threads and cooperating threads are described in more detail, in accordance with one embodiment below. 
       FIG. 23  illustrates a GPC  2300  such as the GPC illustrated of the PPU  2200  of  FIG. 22 , in accordance with one embodiment. In an embodiment, each GPC  2300  includes a number of hardware units for processing tasks and each GPC  2300  includes a pipeline manager  2302 , a pre-raster operations unit (“PROP”)  2304 , a raster engine  2308 , a work distribution crossbar (“WDX”)  2316 , a memory management unit (“MMU”)  2318 , one or more Data Processing Clusters (“DPCs”)  2306 , and any suitable combination of parts. It will be appreciated that the GPC  2300  of  FIG. 23  may include other hardware units in lieu of or in addition to the units shown below. 
     In an embodiment, the operation of the GPC  2300  is controlled by the pipeline manager  2302 . The pipeline manager  2302  manages the configuration of the one or more DPCs  2306  for processing tasks allocated to the GPC  2300 . In an embodiment, the pipeline manager  2302  configures at least one of the one or more DPCs  2306  to implement at least a portion of a graphics rendering pipeline. In an embodiment, a DPC  2306  is configured to execute a vertex shader program on the programmable streaming multiprocessor (“SM”)  2314 . The pipeline manager  2302  is configured to route packets received from a work distribution to the appropriate logical units within the GPC  2300 , in an embodiment, and some packets may be routed to fixed function hardware units in the PROP  2304  and/or raster engine  2308  while other packets may be routed to the DPCs  2306  for processing by the primitive engine  2312  or the SM  2314 . In an embodiment, the pipeline manager  2302  configures at least one of the one or more DPCs  2306  to implement a neural network model and/or a computing pipeline. 
     The PROP unit  2304  is configured, in an embodiment, to route data generated by the raster engine  2308  and the DPCs  2306  to a Raster Operations (“ROP”) unit in the memory partition unit, described in more detail above. In an embodiment, the PROP unit  2304  is configured to perform optimizations for color blending, organize pixel data, perform address translations, and more. The raster engine  2308  includes a number of fixed function hardware units configured to perform various raster operations, in an embodiment, and the raster engine  2308  includes a setup engine, a coarse raster engine, a culling engine, a clipping engine, a fine raster engine, a tile coalescing engine, and any suitable combination thereof. The setup engine, in an embodiment, receives transformed vertices and generates plane equations associated with the geometric primitive defined by the vertices; the plane equations are transmitted to the coarse raster engine to generate coverage information (e.g., an x, y coverage mask for a tile) for the primitive; the output of the coarse raster engine is transmitted to the culling engine where fragments associated with the primitive that fail a z-test are culled, and transmitted to a clipping engine where fragments lying outside a viewing frustum are clipped. In an embodiment, the fragments that survive clipping and culling are passed to the fine raster engine to generate attributes for the pixel fragments based on the plane equations generated by the setup engine. In an embodiment, the output of the raster engine  2308  comprises fragments to be processed by any suitable entity such as by a fragment shader implemented within a DPC  2306 . 
     In an embodiment, each DPC  2306  included in the GPC  2300  comprises an M-Pipe Controller (“MPC”)  2310 ; a primitive engine  2312 ; one or more SMs  2314 ; and any suitable combination thereof. In an embodiment, the MPC  2310  controls the operation of the DPC  2306 , routing packets received from the pipeline manager  2302  to the appropriate units in the DPC  2306 . In an embodiment, packets associated with a vertex are routed to the primitive engine  2312 , which is configured to fetch vertex attributes associated with the vertex from memory; in contrast, packets associated with a shader program may be transmitted to the SM  2314 . 
     In an embodiment, the SM  2314  comprises a programmable streaming processor that is configured to process tasks represented by a number of threads. In an embodiment, the SM  2314  is multi-threaded and configured to execute a plurality of threads (e.g., 32 threads) from a particular group of threads concurrently and implements a SIMD (Single-Instruction, Multiple-Data) architecture where each thread in a group of threads (e.g., a warp) is configured to process a different set of data based on the same set of instructions. In an embodiment, all threads in the group of threads execute the same instructions. In an embodiment, the SM  2314  implements a SIMT (Single-Instruction, Multiple Thread) architecture wherein each thread in a group of threads is configured to process a different set of data based on the same set of instructions, but where individual threads in the group of threads are allowed to diverge during execution. In an embodiment, a program counter, call stack, and execution state is maintained for each warp, enabling concurrency between warps and serial execution within warps when threads within the warp diverge. In another embodiment, a program counter, call stack, and execution state is maintained for each individual thread, enabling equal concurrency between all threads, within and between warps. In an embodiment, execution state is maintained for each individual thread, and threads executing the same instructions may be converged and executed in parallel for better efficiency. In an embodiment, the SM  2314  is described in more detail below. 
     In an embodiment, the MMU  2318  provides an interface between the GPC  2300  and the memory partition unit and the MMU  2318  provides translation of virtual addresses into physical addresses, memory protection, and arbitration of memory requests. In an embodiment, the MMU  2318  provides one or more translation lookaside buffers (“TLBs”) for performing translation of virtual addresses into physical addresses in memory. 
       FIG. 24  illustrates a memory partition unit of a PPU, in accordance with one embodiment. In an embodiment, the memory partition unit  2400  includes a Raster Operations (“ROP”) unit  2402 ; a level two (“L2”) cache  2404 ; a memory interface  2406 ; and any suitable combination thereof. The memory interface  2406  is coupled to the memory. Memory interface  2406  may implement 32, 64, 128, 1024-bit data buses, or the like, for high-speed data transfer. In an embodiment, the PPU incorporates U memory interfaces  2406 , one memory interface  2406  per pair of partition units  2400 , where each pair of partition units  2400  is connected to a corresponding memory device. For example, PPU may be connected to up to Y memory devices, such as high bandwidth memory stacks or graphics double-data-rate, version 5, synchronous dynamic random access memory (“GDDR5 SDRAM”). 
     In an embodiment, the memory interface  2406  implements an HBM2 memory interface and Y equals half U. In an embodiment, the HBM2 memory stacks are located on the same physical package as the PPU, providing substantial power and area savings compared with conventional GDDR5 SDRAM systems. In an embodiment, each HBM2 stack includes four memory dies and Y equals 4, with HBM2 stack including two 128-bit channels per die for a total of 8 channels and a data bus width of 1024 bits. 
     In an embodiment, the memory supports Single-Error Correcting Double-Error Detecting (“SECDED”) Error Correction Code (“ECC”) to protect data. ECC provides higher reliability for compute applications that are sensitive to data corruption. Reliability is especially important in large-scale cluster computing environments where PPUs process very large datasets and/or run applications for extended periods. 
     In an embodiment, the PPU implements a multi-level memory hierarchy. In an embodiment, the memory partition unit  2400  supports a unified memory to provide a single unified virtual address space for CPU and PPU memory, enabling data sharing between virtual memory systems. In an embodiment the frequency of accesses by a PPU to memory located on other processors is traced to ensure that memory pages are moved to the physical memory of the PPU that is accessing the pages more frequently. In an embodiment, the high-speed GPU interconnect  2618  supports address translation services allowing the PPU to directly access a CPU&#39;s page tables and provides full access to CPU memory by the PPU. 
     In an embodiment, copy engines transfer data between multiple PPUs or between PPUs and CPUs. In an embodiment, the copy engines can generate page faults for addresses that are not mapped into the page tables, and the memory partition unit  2400  then services the page faults, mapping the addresses into the page table, after which the copy engine performs the transfer. In an embodiment, memory is pinned (i.e., non-pageable) for multiple copy engine operations between multiple processors, substantially reducing the available memory. In an embodiment, with hardware page faulting, addresses can be passed to the copy engines without regards as to whether the memory pages are resident, and the copy process is transparent. 
     Data from the memory above or other system memory is fetched by the memory partition unit  2400  and stored in the L2 cache  2404 , which is located on-chip and is shared between the various GPCs, in accordance with one embodiment. Each memory partition unit  2400 , in an embodiment, includes at least a portion of the L2 cache  2404  associated with a corresponding memory device. In an embodiment, lower level caches are implemented in various units within the GPCs. In an embodiment, each of the SMs may implement a level one (“L1”) cache wherein the L1 cache is private memory that is dedicated to a particular SM and data from the L2 cache  2404  is fetched and stored in each of the L1 caches for processing in the functional units of the SMs. In an embodiment, the L2 cache  2404  is coupled to the memory interface  2406  and the XBar. 
     The ROP unit  2402  performs graphics raster operations related to pixel color, such as color compression, pixel blending, and more, in an embodiment. The ROP unit  2402 , in an embodiment, implements depth testing in conjunction with the raster engine  2408 , receiving a depth for a sample location associated with a pixel fragment from the culling engine of the raster engine. In an embodiment, the depth is tested against a corresponding depth in a depth buffer for a sample location associated with the fragment. In an embodiment, if the fragment passes the depth test for the sample location, then the ROP unit  2402  updates the depth buffer and transmits a result of the depth test to the raster engine. It will be appreciated that the number of partition units  2400  may be different than the number of GPCs and, therefore, each ROP unit  2402  can, in an embodiment, be coupled to each of the GPCs. In an embodiment, the ROP unit  2402  tracks packets received from the different GPCs and determines which result generated by the ROP unit  2402  is routed to through the Xbar. 
       FIG. 25  illustrates a streaming multi-processor such as the streaming multi-processor above, in accordance with one embodiment. In an embodiment, the SM  2500  includes: an instruction cache  2502 ; one or more scheduler units  2504 ; a register file  2508 ; one or more processing cores  2510 ; one or more special function units (“SFUs”)  2512 ; one or more load/store units (“LSUs”)  2514 ; an interconnect network  2516 ; a shared memory/L1 cache  2518 ; and any suitable combination thereof. In an embodiment, the work distribution unit dispatches tasks for execution on the GPCs of the PPU and each task is allocated to a particular DPC within a GPC and, if the task is associated with a shader program, the task is allocated to an SM  2500 . In an embodiment, the scheduler unit  2504  receives the tasks from the work distribution unit and manages instruction scheduling for one or more thread blocks assigned to the SM  2500 . In an embodiment, the scheduler unit  2504  schedules thread blocks for execution as warps of parallel threads, wherein each thread block is allocated at least one warp. In an embodiment, each warp executes threads. In an embodiment, the scheduler unit  2504  manages a plurality of different thread blocks, allocating the warps to the different thread blocks and then dispatching instructions from the plurality of different cooperative groups to the various functional units (e.g., cores  2510 , SFUs  2512 , and LSUs  2514 ) during each clock cycle. 
     Cooperative Groups may refer to a programming model for organizing groups of communicating threads that allows developers to express the granularity at which threads are communicating, enabling the expression of richer, more efficient parallel decompositions. In an embodiment, cooperative launch APIs support synchronization among thread blocks for the execution of parallel algorithms. In an embodiment, applications of conventional programming models provide a single, simple construct for synchronizing cooperating threads: a barrier across all threads of a thread block (e.g., the syncthreads( ) function). However, programmers would often like to define groups of threads at smaller than thread block granularities and synchronize within the defined groups to enable greater performance, design flexibility, and software reuse in the form of collective group-wide function interfaces. Cooperative Groups enable programmers to define groups of threads explicitly at sub-block (i.e., as small as a single thread) and multi-block granularities, and to perform collective operations such as synchronization on the threads in a cooperative group. The programming model supports clean composition across software boundaries so that libraries and utility functions can synchronize safely within their local context without having to make assumptions about convergence. Cooperative Groups primitives enable new patterns of cooperative parallelism, including producer-consumer parallelism, opportunistic parallelism, and global synchronization across an entire grid of thread blocks. 
     In an embodiment, a dispatch unit  2506  is configured to transmit instructions to one or more of the functional units, and the scheduler unit  2504  includes two dispatch units  2506  that enable two different instructions from the same warp to be dispatched during each clock cycle. In an embodiment, each scheduler unit  2504  includes a single dispatch unit  2506  or additional dispatch units  2506 . 
     Each SM  2500 , in an embodiment, includes a register file  2508  that provides a set of registers for the functional units of the SM  2500 . In an embodiment, the register file  2508  is divided between each of the functional units such that each functional unit is allocated a dedicated portion of the register file  2508 . In an embodiment, the register file  2508  is divided between the different warps being executed by the SM  2500  and the register file  2508  provides temporary storage for operands connected to the data paths of the functional units. In an embodiment, each SM  2500  comprises a plurality of L processing cores  2510 . In an embodiment, the SM  2500  includes a large number (e.g., 128 or more) of distinct processing cores  2510 . Each core  2510 , in an embodiment, includes a fully pipelined, single-precision, double-precision, and/or mixed precision processing unit that includes a floating point arithmetic logic unit and an integer arithmetic logic unit. In an embodiment, the floating point arithmetic logic units implement the IEEE 754-2008 standard for floating point arithmetic. In an embodiment, the cores  2510  include 64 single-precision (32-bit) floating point cores, 64 integer cores, 32 double-precision (64-bit) floating point cores, and 8 tensor cores. 
     Tensor cores are configured to perform matrix operations in accordance with an embodiment. In an embodiment, one or more tensor cores are included in the cores  2510 . In an embodiment, the tensor cores are configured to perform deep learning matrix arithmetic, such as convolution operations for neural network training and inferencing. In an embodiment, each tensor core operates on a 4×4 matrix and performs a matrix multiply and accumulate operation D=A×B+C, where A, B, C, and D are 4×4 matrices. 
     In an embodiment, the matrix multiply inputs A and B are 16-bit floating point matrices and the accumulation matrices C and D are 16-bit floating point or 32-bit floating point matrices. In an embodiment, the tensor cores operate on 16-bit floating point input data with 32-bit floating point accumulation. In an embodiment, the 16-bit floating point multiply requires 64 operations and results in a full precision product that is then accumulated using 32-bit floating point addition with the other intermediate products for a 4×4×4 matrix multiply. Tensor cores are used to perform much larger two-dimensional or higher dimensional matrix operations, built up from these smaller elements, in an embodiment. In an embodiment, an API, such as CUDA 9 C++ API, exposes specialized matrix load, matrix multiply and accumulate, and matrix store operations to efficiently use tensor cores from a CUDA-C++ program. In an embodiment, at the CUDA level, the warp-level interface assumes 16×16 size matrices spanning all 32 threads of the warp. 
     In an embodiment, each SM  2500  comprises M SFUs  2512  that perform special functions (e.g., attribute evaluation, reciprocal square root, and the like). In an embodiment, the SFUs  2512  include a tree traversal unit configured to traverse a hierarchical tree data structure. In an embodiment, the SFUs  2512  include a texture unit configured to perform texture map filtering operations. In an embodiment, the texture units are configured to load texture maps (e.g., a 2D array of texels) from the memory and sample the texture maps to produce sampled texture values for use in shader programs executed by the SM  2500 . In an embodiment, the texture maps are stored in the shared memory/L1 cache. The texture units implement texture operations such as filtering operations using mip-maps (e.g., texture maps of varying levels of detail), in accordance with one embodiment. In an embodiment, each SM  2500  includes two texture units. 
     Each SM  2500  comprises N LSUs that implement load and store operations between the shared memory/L1 cache and the register file  2508 , in an embodiment. Each SM  2500  includes an interconnect network  2516  that connects each of the functional units to the register file  2508  and the LSU  2514  to the register file  2508 , shared memory/L1 cache  2518  in an embodiment. In an embodiment, the interconnect network  2516  is a crossbar that can be configured to connect any of the functional units to any of the registers in the register file  2508  and connect the LSUs  2514  to the register file and memory locations in shared memory/L1 cache  2518 . 
     The shared memory/L1 cache  2518  is an array of on-chip memory that allows for data storage and communication between the SM  2500  and the primitive engine and between threads in the SM  2500  in an embodiment. In an embodiment, the shared memory/L1 cache  2518  comprises 128 KB of storage capacity and is in the path from the SM  2500  to the partition unit. The shared memory/L1 cache  2518 , in an embodiment, is used to cache reads and writes. One or more of the shared memory/L1 cache  2518 , L2 cache, and memory are backing stores. 
     Combining data cache and shared memory functionality into a single memory block provides improved performance for both types of memory accesses, in an embodiment. The capacity, in an embodiment, is used or is usable as a cache by programs that do not use shared memory, such as if shared memory is configured to use half of the capacity, texture and load/store operations can use the remaining capacity. Integration within the shared memory/L1 cache  2518  enables the shared memory/L1 cache  2518  to function as a high-throughput conduit for streaming data while simultaneously providing high-bandwidth and low-latency access to frequently reused data, in accordance with an embodiment. When configured for general purpose parallel computation, a simpler configuration can be used compared with graphics processing. In an embodiment, fixed function graphics processing units are bypassed, creating a much simpler programming model. In the general purpose parallel computation configuration, the work distribution unit assigns and distributes blocks of threads directly to the DPCs, in an embodiment. The threads in a block execute the same program, using a unique thread ID in the calculation to ensure each thread generates unique results, using the SM  2500  to execute the program and perform calculations, shared memory/L1 cache  2518  to communicate between threads, and the LSU  2514  to read and write global memory through the shared memory/L1 cache  2518  and the memory partition unit, in accordance with one embodiment. In an embodiment, when configured for general purpose parallel computation, the SM  2500  writes commands that the scheduler unit can use to launch new work on the DPCs. 
     In an embodiment, the PPU is included in or coupled to a desktop computer, a laptop computer, a tablet computer, servers, supercomputers, a smart-phone (e.g., a wireless, hand-held device), personal digital assistant (“PDA”), a digital camera, a vehicle, a head mounted display, a hand-held electronic device, and more. In an embodiment, the PPU is embodied on a single semiconductor substrate. In an embodiment, the PPU is included in a system-on-a-chip (“SoC”) along with one or more other devices such as additional PPUs, the memory, a reduced instruction set computer (“RISC”) CPU, a memory management unit (“MMU”), a digital-to-analog converter (“DAC”), and the like. 
     In an embodiment, the PPU may be included on a graphics card that includes one or more memory devices. The graphics card may be configured to interface with a PCIe slot on a motherboard of a desktop computer. In yet another embodiment, the PPU may be an integrated graphics processing unit (“iGPU”) included in the chipset of the motherboard. 
       FIG. 26  illustrates a computer system  2600  in which the various architecture and/or functionality can be implemented, in accordance with one embodiment. The computer system  2600 , in an embodiment, is configured to implement various processes and methods described throughout this disclosure. 
     In an embodiment, the computer system  2600  comprises at least one central processing unit  2602  that is connected to a communication bus  2610  implemented using any suitable protocol, such as PCI (Peripheral Component Interconnect), PCI-Express, AGP (Accelerated Graphics Port), HyperTransport, or any other bus or point-to-point communication protocol(s). In an embodiment, the computer system  2600  includes a main memory  2604  and control logic (e.g., implemented as hardware, software, or a combination thereof) and data are stored in the main memory  2604  which may take the form of random access memory (“RAM”). In an embodiment, a network interface subsystem  2622  provides an interface to other computing devices and networks for receiving data from and transmitting data to other systems from the computer system  2600 . 
     The computer system  2600 , in an embodiment, includes input devices  2608 , the parallel processing system  2612 , and display devices  2606  which can be implemented using a conventional CRT (cathode ray tube), LCD (liquid crystal display), LED (light emitting diode), plasma display, or other suitable display technologies. In an embodiment, user input is received from input devices  2608  such as keyboard, mouse, touchpad, microphone, and more. In an embodiment, each of the foregoing modules can be situated on a single semiconductor platform to form a processing system. 
     In the present description, a single semiconductor platform may refer to a sole unitary semiconductor-based integrated circuit or chip. It should be noted that the term single semiconductor platform may also refer to multi-chip modules with increased connectivity which simulate on-chip operation, and make substantial improvements over utilizing a conventional central processing unit (“CPU”) and bus implementation. Of course, the various modules may also be situated separately or in various combinations of semiconductor platforms per the desires of the user. 
     In an embodiment, computer programs in the form of machine-readable executable code or computer control logic algorithms are stored in the main memory  2604  and/or secondary storage. Computer programs, if executed by one or more processors, enable the computer system  2600  to perform various functions in accordance with one embodiment. The memory  2604 , the storage, and/or any other storage are possible examples of computer-readable media. Secondary storage may refer to any suitable storage device or system such as a hard disk drive and/or a removable storage drive, representing a floppy disk drive, a magnetic tape drive, a compact disk drive, digital versatile disk (“DVD”) drive, recording device, universal serial bus (“USB”) flash memory. 
     In an embodiment, the architecture and/or functionality of the various previous figures are implemented in the context of the central processor  2602 ; parallel processing system  2612 ; an integrated circuit capable of at least a portion of the capabilities of both the central processor  2602 ; the parallel processing system  2612 ; a chipset (e.g., a group of integrated circuits designed to work and sold as a unit for performing related functions, etc.); and any suitable combination of integrated circuit. 
     In an embodiment, the architecture and/or functionality of the various previous figures is implemented in the context of a general computer system, a circuit board system, a game console system dedicated for entertainment purposes, an application-specific system, and more. In an embodiment, the computer system  2600  may take the form of a desktop computer, a laptop computer, a tablet computer, servers, supercomputers, a smart-phone (e.g., a wireless, hand-held device), personal digital assistant (“PDA”), a digital camera, a vehicle, a head-mounted display, a hand-held electronic device, a mobile phone device, a television, workstation, game consoles, embedded system, and/or any other type of logic. 
     In an embodiment, a parallel processing system  2612  includes a plurality of PPUs  2614  and associated memories  2616 . In an embodiment, the PPUs are connected to a host processor or other peripheral devices via an interconnect  2618  and a switch  2620  or multiplexer. In an embodiment, the parallel processing system  2612  distributes computational tasks across the PPUs  2614  which can be parallelizable—for example, as part of the distribution of computational tasks across multiple GPU thread blocks. In an embodiment, memory is shared and accessible (e.g., for read and/or write access) across some or all of the PPUs  2614 , although such shared memory may incur performance penalties relative to the use of local memory and registers resident to a PPU. In an embodiment, the operation of the PPUs  2614  is synchronized through the use of a command such as _syncthreads( ) which requires all threads in a block (e.g., executed across multiple PPUs  2614 ) to reach a certain point of execution of code before proceeding. 
     The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the claims. 
     Other variations are within the spirit of the present disclosure. Thus, while the disclosed techniques are susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific form or forms disclosed but, on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the disclosed embodiments (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including but not limited to,”) unless otherwise noted. The term “connected,” when unmodified and referring to physical connections, is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein and each separate value is incorporated into the specification as if it were individually recited herein. The use of the term “set” (e.g., “a set of items”) or “subset” unless otherwise noted or contradicted by context, is to be construed as a nonempty collection comprising one or more members. Further, unless otherwise noted or contradicted by context, the term “subset” of a corresponding set does not necessarily denote a proper subset of the corresponding set, but the subset and the corresponding set may be equal. 
     Conjunctive language, such as phrases of the form “at least one of A, B, and C,” or “at least one of A, B and C,” unless specifically stated otherwise or otherwise clearly contradicted by context, is otherwise understood with the context as used in general to present that an item, term, etc., may be either A or B or C, or any nonempty subset of the set of A and B and C. For instance, in the illustrative example of a set having three members, the conjunctive phrases “at least one of A, B, and C” and “at least one of A, B and C” refer to any of the following sets: {A}, {B}, {C}, {A, B}, {A, C}, {B, C}, {A, B, C}. Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of A, at least one of B and at least one of C each to be present. In addition, unless otherwise noted or contradicted by context, the term “plurality” indicates a state of being plural (e.g., “a plurality of items” indicates multiple items). The number of items in a plurality is at least two, but can be more when so indicated either explicitly or by context. Further, unless stated otherwise or otherwise clear from context, the phrase “based on” means “based at least in part on” and not “based solely on.” 
     Operations of processes described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. In an embodiment, a process such as those processes described herein (or variations and/or combinations thereof) is performed under the control of one or more computer systems configured with executable instructions and is implemented as code (e.g., executable instructions, one or more computer programs or one or more applications) executing collectively on one or more processors, by hardware or combinations thereof. In an embodiment, the code is stored on a computer-readable storage medium, for example, in the form of a computer program comprising a plurality of instructions executable by one or more processors. In an embodiment, a computer-readable storage medium is a non-transitory computer-readable storage medium that excludes transitory signals (e.g., a propagating transient electric or electromagnetic transmission) but includes non-transitory data storage circuitry (e.g., buffers, cache, and queues) within transceivers of transitory signals. In an embodiment, code (e.g., executable code or source code) is stored on a set of one or more non-transitory computer-readable storage media having stored thereon executable instructions (or other memory to store executable instructions) that, when executed (i.e., as a result of being executed) by one or more processors of a computer system, cause the computer system to perform operations described herein. The set of non-transitory computer-readable storage media, in an embodiment, comprises multiple non-transitory computer-readable storage media and one or more of individual non-transitory storage media of the multiple non-transitory computer-readable storage media lack all of the code while the multiple non-transitory computer-readable storage media collectively store all of the code. In an embodiment, the executable instructions are executed such that different instructions are executed by different processors—for example, a non-transitory computer-readable storage medium store instructions and a main CPU execute some of the instructions while a graphics processor unit executes other instructions. In an embodiment, different components of a computer system have separate processors and different processors execute different subsets of the instructions. 
     Accordingly, in an embodiment, computer systems are configured to implement one or more services that singly or collectively perform operations of processes described herein and such computer systems are configured with applicable hardware and/or software that enable the performance of the operations. Further, a computer system that implement an embodiment of the present disclosure is a single device and, in another embodiment, is a distributed computer system comprising multiple devices that operate differently such that the distributed computer system performs the operations described herein and such that a single device does not perform all operations. 
     The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Embodiments of this disclosure are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate and the inventors intend for embodiments of the present disclosure to be practiced otherwise than as specifically described herein. Accordingly, the scope of the present disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the scope of the present disclosure unless otherwise indicated herein or otherwise clearly contradicted by context. 
     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     In the description and claims, the terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms may be not intended as synonyms for each other. Rather, in particular examples, “connected” or “coupled” may be used to indicate that two or more elements are in direct or indirect physical or electrical contact with each other. “Coupled” may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. 
     Unless specifically stated otherwise, it may be appreciated that throughout the specification terms such as “processing,” “computing,” “calculating,” “determining,” or the like, refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulate and/or transform data represented as physical, such as electronic, quantities within the computing system&#39;s registers and/or memories into other data similarly represented as physical quantities within the computing system&#39;s memories, registers or other such information storage, transmission or display devices. 
     In a similar manner, the term “processor” may refer to any device or portion of a device that processes electronic data from registers and/or memory and transform that electronic data into other electronic data that may be stored in registers and/or memory. As non-limiting examples, “processor” may be a Central Processing Unit (CPU) or a Graphics Processing Unit (GPU). A “computing platform” may comprise one or more processors. As used herein, “software” processes may include, for example, software and/or hardware entities that perform work over time, such as tasks, threads, and intelligent agents. Also, each process may refer to multiple processes, for carrying out instructions in sequence or in parallel, continuously or intermittently. The terms “system” and “method” are used herein interchangeably insofar as the system may embody one or more methods and the methods may be considered a system. 
     In the present document, references may be made to obtaining, acquiring, receiving, or inputting analog or digital data into a subsystem, computer system, or computer-implemented machine. The process of obtaining, acquiring, receiving, or inputting analog and digital data can be accomplished in a variety of ways such as by receiving the data as a parameter of a function call or a call to an application programming interface. In some implementations, the process of obtaining, acquiring, receiving, or inputting analog or digital data can be accomplished by transferring the data via a serial or parallel interface. In another implementation, the process of obtaining, acquiring, receiving, or inputting analog or digital data can be accomplished by transferring the data via a computer network from the providing entity to the acquiring entity. References may also be made to providing, outputting, transmitting, sending, or presenting analog or digital data. In various examples, the process of providing, outputting, transmitting, sending, or presenting analog or digital data can be accomplished by transferring the data as an input or output parameter of a function call, a parameter of an application programming interface or interprocess communication mechanism. 
     Although the discussion above sets forth example implementations of the described techniques, other architectures may be used to implement the described functionality, and are intended to be within the scope of this disclosure. Furthermore, although specific distributions of responsibilities are defined above for purposes of discussion, the various functions and responsibilities might be distributed and divided in different ways, depending on circumstances. 
     Furthermore, although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as exemplary forms of implementing the claims.