Ring-shaped interference pattern illumination

Abstract

This document describes systems and techniques for generating illumination including a ring-shaped interference pattern. For example, a system includes a light source configured to generate light that is at least substantially coherent. A body that is at least partially-transparent to the at least substantially coherent light receives the at least substantially coherent light at a proximal side of the body, transmits a first portion of photons of the at least substantially coherent light from the proximal side of the body through a distal side of the body, and reflects a second portion of photons of the at least substantially coherent light between internal surfaces of the body to shift a phase of the second portion of photons before transmitting them through the distal side. The first portion of photons and the second portion of photons interfere with each other to generate the ring-shaped interference pattern.

Description

RING-SHAPED INTERFERENCE PATTERN ILLUMINATIONBACKGROUND

[0001] Many electronic devices, such as smartphones or other computing devices, include light sources and cameras or other sensors utilized to perform image analysis and recognition. For example, it may be useful for any number of electronic devices to be able to determine distances to one or more objects in proximity to those devices. For example, any self-driven appliance may need to determine a distance to one or more nearby objects to be able to navigate toward and / or around those objects. Any device that accepts input in the form of gestures may need to identify positions of or distances to a hand or other object performing the gestures to interpret what gestures are being presented. For another example, some devices use facial recognition to authenticate a user to access the device or to access information on the device. To perform facial recognition, these devices may be configured to identify distances to different aspects of a face and determine if that face is one that is authorized to access the device.

[0002] To facilitate facial recognition, some devices incorporate specialized projectors (e.g., dot-pattern projectors, fringe projectors) to cast a known pattern of light onto a face or other objects. An image processing system then can evaluate captured image data to determine, from the shape and length of the patterns as they appear on faces or other objects, how far away portions of the face or objects are from the device and, in turn, attempt to recognize the face or other objects.

[0003] However, the use of dot-pattern and fringe projectors presents disadvantages. The design of these specialized projectors for different devices may be costly. Further, manufacturing and installing these specialized proj ectors in devices appreciably adds to the cost of the devices.In addition, the specialized projectors take up space which may be at a premium, particularly in compact devices such as smartphones.SUMMARY

[0004] This document describes systems and techniques for generating illumination including a ring-shaped interference pattern illumination from which light reflected from an object may be analyzed to determine distances to points on the object.

[0005] For example, a system includes a light source configured to generate light that is at least substantially coherent. A body that is at least parti ally-transparent to the at least substantially coherent light is configured to receive the at least substantially coherent light at a proximal side of the body, transmit a first portion of photons of the at least substantially coherent light from the proximal side of the body through a distal side of the body, and reflect a second portion of photons of the at least substantially coherent light between internal surfaces of the body at the distal side and the proximal side. Reflecting a second portion of the photons shifts a phase of the second portion of photons before transmitting the second portion of photons through the distal side, the first portion of photons and the second portion of photons of the at least substantially coherent light interfering with each other to generate illumination having a ring-shaped interference pattern.

[0006] For another example, a method comprises generating illumination that includes at least substantially coherent light. The at least substantially coherent light is received at a proximal side of a body. A first portion of photons of the at least substantially coherent light is transmitted from the proximal side of the body through a distal side of the body. A second portion of photons of the at least substantially coherent light is reflected between internal surfaces of the body to shift a phase of the second portion of photons before transmitting the second portion of photons through the distal side, the first portion of photons and the second portion of photons of the at leastsubstantially coherent light interfering with each other to generate illumination having a ringshaped interference pattern. A portion of the illumination reflected from an object is received. The received portion of the illumination is analyzed to determine a distance from the body to a plurality of points of the object based on attributes of the ring-shaped interference pattern.

[0007] For another example, an article of manufacture includes one or more non-transitory computer-readable media, having stored thereon program instructions that, upon execution by a processor of an electronic device, cause the electronic device to perform the foregoing method.

[0008] For another example, a computer-readable medium includes program instructions stored thereon that cause a processor of an electronic device to perform the foregoing method.

[0009] This Summary is provided to introduce systems and techniques for generating illumination including a ring-shaped interference pattern, as further described below in the Detailed Description and Drawings. This Summary' is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The details of one or more aspects of systems and techniques for generating illumination including a display-induced interference pattern are described in this document with reference to the following Drawings. The same numbers are used throughout the drawings to reference like features and components.

[0011] FIG. 1 is a schematic diagram of a system configured to generate illumination and then analyze reflected light to determine a distance to one or more points;

[0012] FIGS. 2A-2E are cross-sectional diagrams of display devices configured to facilitate a light source generating the illumination as shown in the system of FIG. 1 ;

[0013] FIG. 3 is a cross-sectional view of an image processing subsystem of the system of FIG. 1, which is configured to generate a ring-shaped interference pattern;

[0014] FIG. 4 is a schematic diagram of illumination including a ring-shaped interference pattern generated by the system of FIG. 1;

[0015] FIG. 5 is a schematic diagram of the illumination including the ring-shaped interference pattern of FIG. 4 cast on an object such as a face;

[0016] FIG. 6 is a flow diagram of an example method of generating a ring-shaped interference pattern;

[0017] FIG. 7 is a schematic diagram of the system of FIG. 1 that illustrates using triangulation to measure distances to points on an object from a portion of the illumination reflected by the object;

[0018] FIG. 8 is a depth map of an object, such as the face of FIG. 5, from which reflected light is captured;

[0019] FIG. 9 is an authenticated depth map of an authorized user with which the depth map of FIG. 8 may be compared;

[0020] FIG. 10 is a flow diagram of an example method of using triangulation to determine distances to points on an object using the system of FIG. 1;

[0021] FIG. 11 illustrates a machine-learned model in the form of a neural network that may be used to identify an object using the system of FIG. 1;

[0022] FIG. 12 illustrates reference data that may be used to train and tune the machine-learned structure of FIG. 11;

[0023] FIG. 13 is a flow diagram of an example method of measuring distance by analyzing reflected portions of light including the ring-shaped interference pattern;

[0024] FIG. 14 is a flow diagram of an example method of using the machine-learned structure of FIG. 11 to determine distances to an object;

[0025] FIG. 15 is a flow diagram of an example method of using the machine-learned model of FIG. 11 to differentiate between actual and human faces; and

[0026] FIG. 16 is a schematic diagram of electronic devices that may include an aspect of the system of FIG. 1.DETAILED DESCRIPTION OVERVIEW

[0027] According to implementations described herein, instead of using a dedicated, specialized projector, substantially coherent light transmitted through an at least partially -transparent body results in some portions of the light being transmitted directly through the body while other portions reflect between internal surfaces of the body, thereby shifting the phase of the reflected photons. Interaction between the phase-shifted photons and photons that are transmitted directly through the body may result in varying degrees of constructive and destructive interference. Transmitting the at least substantially coherent light through the partially-transparent body generates illumination with a ring-shaped interference pattern. Instead of depending on a dot-pattern or other specially designed proj ector to generate a pattern that can be used to determine distances to points on an object, analyzing a portion of the illumination including the ring-shaped interference pattern that is reflected from an object allows for distances to points on the object to be determined based on where points on the object are located relative to the ring-shaped interference pattern.

[0028] The light including the at least substantially coherent light may be outside of a human visible spectrum. For example, the light including the at least substantially coherent light may include non-visible ultra-violet light or non-visible infra-red light.REPRESENTATIVE SYSTEM AND OPERATING ENVIRONMENT

[0029] FIG. 1 depicts an electronic device 100, such as a smartphone or other mobile telephone, which includes an at least partially -transparent body 102 such a display screen on which a user views information and / or interacts with a graphical user interface or other user interface. The body 102, or at least an at least partially-transparent section 104 of the body 102, may enable light to pass outward through the body and / or receive light from external objects, such as light that may be generated by components within the electronic device 100 and then reflected back to the electronic device 100.

[0030] For illustration, the electronic device 100 includes an imaging subsystem 106 that may be included within the electronic device 100. The imaging subsystem 106 includes a light source 108 that is configured to generate light 110 that includes light which is at least substantially temporally coherent in frequency and wavelength and in which photons of the light are substantially in phase upon being generated. A laser is an example of a light source capable of generating coherent light. Other devices, such as small gas discharge lamps, which generate light by passing an electric charge through an ionized plasma, also may generate at least substantially coherent light. In aspects, the light 110 generated by the light source 108 may be outside of a human-visible spectrum including ultraviolet and / or infrared light.

[0031] As further described with reference to FIG. 2, the light 110 is transmitted through the at least partially-transparent body 102 (or the at least partially-transparent section 104 of the body 102) toward an object 112 which, in this example, is a person. The light 110 illuminates andis reflected by a plurality of points 114 on the object 112 which, in this example, are points on the face of the person. As further described below, a ring-shaped interference pattern results from a first portion of photons of the at least substantially coherent light being transmitted through the at least substantially transparent body while a second portions of photons are reflected by internal surfaces of the at least partially-transparent body and then transmitted through the at least partially -transparent body.

[0032] Reflected light 116, reflected from the plurality of points 114 on the object 112, are received by a sensor 1 18. The reflected light 116 includes reflections of the ring-shaped interference pattern. The sensor 1 18 may include a lens 120 or a similar focusing mechanism to refract the reflected light 116 to enhance spatial evaluation of the reflected light 116. As further described below, an angle at which the reflected light 116 and aspects of the ring-shaped interference pattern included in the reflected light 116 may be used to triangulate or otherwise evaluate the reflected light 116 to determine a distance to the points 114 on the object 112.

[0033] An image processing subsystem 122 receives signals from the sensor 118 based on the reflected light 116 that may be used to identify the distance to the points on the object 112. The image processing subsystem 122 may use triangulation or machine learning to process the data received from the sensor 118 in order to determine a distance to the object 112 from which the reflected light 116 is received, as described further below.

[0034] In aspects, the body 102 may include a display screen of an electronic device, such as the display screen of a wireless telephone, a computer, or another device incorporating a display screen as described below with reference to FIG. 15. FIGS. 2A-2E show different configurations of display screens that are configured to accommodate or incorporate the light source 108 (see FIG. 1) that is used to generate the light 110 that causes formation of the ring-shaped interference pattern. In aspects, it may be desired to include the light source 108 within or beneath the displayscreen so that the light source 108 may be unobtrusively added to the device. As stated and as further described below, a first portion of photons of the light 110 generated by the light source 108 are transmitted directly through a glass layer 202 while a second portion of photons of the light 110 are reflected by internal surfaces of the glass layer before the second portion of photons of the light 110 are transmitted out of the glass layer. Understandably, it may be necessary to form the display screen so that the light 110 generated by the light source 108 is not blocked or impaired by other aspects of the display screen as the light travels to and through the glass layer.

[0035] FIG. 2A shows a conventional liquid crystal display (LCD) display screen 200 configured to accommodate the light source 108. The display screen 200 includes several layers including a glass layer 202 that is at least substantially transparent. Beneath the glass layer 202, the display screen may include at least one of a polarizing layer 204, a color filter layer 206, and / or a liquid crystal display layer 208 that generates images and / or text, as understood by those skilled in the art. A backlight layer 210 beneath the crystal display layer 208 provides illumination to the images and / or text produced by the liquid crystal display layer 208 to enable the images and / or text to be viewed on the display screen 200.

[0036] The light source 108 may be positioned beneath the layers 202. 204, 206, 208. and 210 of the display screen 200 with an opening 212 formed in the layers 204, 206. 208, and 210 to allow the light 110 generated by the light source 108 to reach the glass layer 202. The layers 204, 206, 208, and 210 of the display screen 200 behind the glass layer 202 may not be sufficiently transparent to allow the light 110 generated by the light source 108 to pass therethrough substantially unimpeded, thus, it may be desired to form or otherwise incorporate the opening 212 in the layers 204, 206, 208, and 210 to allow the light 110 generated by the light source 108 to reach the glass layer 202 without obstruction.

[0037] It is noted that the glass layer 202 is used generically to describe an at least substantially transparent material that is used to form a top-most layer of the display screen 200. For purposes of this description, the glass layer could include a polymer or plastic layer, such as plexiglass, which also may be used to provide a substantially transparent cover layer for the display screen 200.

[0038] Referring to FIG. 2B, a display screen 214 shows that the light source 108 need not be positioned beneath all of the layers 202, 204, 206, 208, and 210 of the display screen 218. In the display screen 218, the light source 108 could be installed on or incorporated within a recess 216 formed within one or more of the other layers 204, 206, 208, and 210 of the display screen 218 behind the glass layer 202 through which the light 110 generated by the light source 108 passes.

[0039] Other types of display screens also may incorporate the light source 108. For example, FIG. 2C shows an organic light emitting diode (OLED) display screen 218. In the OLED display screen 218. beneath the glass layer 202, an anode layer 220. an organic emitter layer 222, and a cathode layer 224, respectively, may be positioned. As in the example of FIGS. 2A and 2B, the layers 220, 222, and 224 may not be sufficiently transparent to allow the light 110 generated by the light source 108 to pass therethrough substantially unimpeded, thus, it may be desired to form or otherwise incorporate an opening 226 in the layers 220, 222, and 224 to allow the light 110 generated by the light source 108 to reach the glass layer 202 without obstruction. Correspondingly, instead of including the recess 226 within the layers 220, 222. and 224, FIG. 2D shows a display screen 228 in which the light source 108 is installed on or incorporated within a recess 230 formed one or more of the other layers 220, 222, and 224 of the display screen 218 behind the glass layer 202 through which the light 110 generated by the light source 108 passes.

[0040] In addition, the light source 108 could be incorporated within a display screen behind the glass layer 202 and adjacent to other layers. Referring to FIG. 2E, a display screen 232 includes a “cutout’’ or an edge to which the glass layer 202 extends while other layers, such as the anode layer 220, the organic emitter layer 222, and the cathode layer 224 of FIGS. 2C and 2D, extend to an end 234 beneath the glass layer 202. Positioning the light source 108 beyond the end 234 of the other layers 220, 222, and 224 in the display screen 232, the light source 208 is still unobtrusively positioned behind the glass layer 202 through which the light 110 generated by the light source 108 passes.

[0041] FIG. 3 shows an enlarged view of the light source 108 and a section of the at least partially -transparent body 102 through which the light 110 generated by the light source 108 is transmitted. As previously described, the light source 108 generates photons 300, 302, 304, 306, and 308 that are substantially coherent in frequency, wavelength, and phase as they are emitted by the light source 108. It will be appreciated that countless photons may be emitted by the light source 1 8, some of which pass through the at least parti ally -transparent body 102 (from this point forward, just “the body 102”) and some of which will be reflected one or many times internally to the body 102 between a proximal side 310 and a distal side 312 of the body 102. For purposes of illustration, the foregoing description details paths of the photons 300, 302. 304, 306, and 308 by way of illustration. It will be appreciated that reflections of the photons 302 and 304 may not be optically accurate but are exaggerated for the sake of illustrating interference resulting from generation and reflection of the photons 300, 302. 304, 306, and 308. The body 102 may be regarded as a portion of the glass layer 202 (FIGS. 2A-2E) adjacent to the light source 108.

[0042] A first photon 300 of light may be generated by the light source 108 perpendicularly to the proximal side 310 of the body 102 and passes out through the distal side 312 of the body 102 in a first direction 314. The first photon 300, for the sake of example, is thus shown as passingdirectly through the body 102 from the proximal side 310 through the distal side 312 without reflection.

[0043] A second photon 302 and a third photon 304 are generated by the light source 108 at an angle a 316 in a second direction 318. Upon being generated at the light source, the second photon 302 and the third photon 304 are coherent in frequency, wavelength, and phase. For the sake of example, upon reaching the distal side 312 of the body 102, the second photon 302 (a first portion of the photons) passes out of the distal side 312 while the third photon 304 (a second portion of the photons) is reflected from a distal interior surface 320 of the distal side 312 of the body 102, causing a first reflected photon 322 (represented in FIG. 3 by a bold dashed line). The first reflected photon 322, upon reaching the proximal side 310 reflects from a proximal interior surface 324 of the proximal side 310 of the body, resulting in a second reflected photon 326 (represented in FIG. 3 by a dotted line) that then exits the distal side 312 in the second direction 318. An extent to which the photons, such as the second photon 302 and the third photon 304, are transmitted through the proximal surface 310 and the distal surface 312 or are reflected by interior surfaces 320 and 324 depends on an index of refraction of the body 102 and as well as coatings applied to the surfaces 310 and 312.

[0044] At a position 328, where the second photon 302 and the second reflected photon 326 propagate in parallel, a peak 330 of the second photon 302 coincides with a trough 332 of the second reflected photon 326. As a result, along the second direction 318 at the angle a 316 relative to the first direction 314 perpendicular to the light source 108, the second photon 302 and the second reflected photon 326 destructively interfere with each other. The destructive interference will result in a dark region in illumination generated by the light source 108, as further described below.

[0045] A fourth photon 306 and a fifth photon 308 are generated by the light source 108 at an angle (3 334 in a third direction 336. As in the case of the second and third photons 302 and 304, upon being generated at the light source 108, the fourth photon 306 and the fifth photon 308 are coherent in frequency, wavelength, and phase. For the sake of example, upon reaching the distal side 312 of the body 102, the fourth photon 306 (a first portion of the photons) passes out of the distal side 312 while the fifth photon 308 (a second portion of the photons) is reflected from the distal interior surface 320 of the distal side 312, causing a third reflected photon 338 (represented in FIG. 3 by a heavy dashed line). The third reflected photon 338, upon reaching the proximal side 310 reflects from the proximal interior surface 324, resulting in a fourth reflected photon 340 (represented in FIG. 3 by a dotted line) that then exits the distal side 312 in the third direction 336. At a position 342, where the fourth photon 306 and the fourth reflected photon 338 propagate in parallel, a peak 344 of the fourth photon 306 coincides with a midpoint of the wave 346 of the fourth reflected photon 340. As a result, along the third direction 336 at the angle (3 334 relative to the first direction 314 perpendicular to the light source 108, the fourth photon 306 and the fourth reflected photon 340 partially constructively interfere with each other, resulting in a brighter region in illumination generated by the light source, as further described below.

[0046] It will be appreciated that photons generated at different angles and in different directions in addition to the photons 300, 302, 304, 306, and 308 will either pass through the body 102, as in the case of the photons 300, 302, and 306 and / or will reflect within the body as in the case of the photons 304 and 308 to effectively shift the phase of the photons 304 and 308 as they are transmitted out of the body as the reflections as in the case of the second reflected photon 326 and the fourth reflected photon 340. Transverse to the first direction 314 perpendicular to the light source 108, the various photons will constructively and destructively interfere with each other to lesser and greater degrees. This interference may result in complete constructive or destructiveinterference, as the second photon 302 and the second reflected photon 326 destructively interfere with each other, or in partial constructive or destructive interference, as the fourth photon 306 and the fourth reflected photon 340 partially, constructively interfere with each other. The generation of photons at different angles, with the photons reflecting and / or passing out of the body 102 in different directions, results in the photons constructively and destructively interfering with each other in a radial pattern all around the light source 108.

[0047] FIG. 4 illustrates illumination 400 which includes a ring-shaped interference pattern 402 that is generated by the light source 108 (see FIGS. 1 and 2) that results from the constructive and destructive interference between the photons as described with reference to FIG. 2. The ringshaped interference pattern 402 includes concentric rings 404 of different levels of magnitude or brightness depending upon how peaks and troughs of photons intersect and interact at locations coinciding with each of the concentric rings 404. Concentric rings 404 where the peaks of photons intersect result in rings of highest brightness or magnitude 406, which appear as the lightest rings in FIG. 4. Concentric rings 404 where the peaks of some photons intersect with troughs of other photons result in rings of lowest brightness or magnitude 408 that appear as the darkest rings in FIG. 4. Concentric rings 404 where peaks or partial peaks or troughs of some photons intersect with partial peaks or troughs of other photons result in rings of intermediate brightness or magnitude 410 having magnitudes ranging between that of the rings of highest magnitude 406 and that of the rings of lowest magnitude 408. The ring-shaped interference pattern 402 thus presents a regular, discernible pattern of magnitudes. For determining distance to objects from the body, angular coordinates may be assigned to each of the concentric rings 404 included in the ringshaped interference pattern 402. For example, angular coordinates, represented in FIG. 4 by angle y 412 and angle 5414 represent the angular coordinates of the first two rings of lowest magnitude 416 and 418, respectively of the ring-shaped interference pattern 402. In the example of FIG. 4.the angle y 412 and the angle 5414 are measured relative to an axis 420 extending from a center 422 of the ring-shaped interference pattern 402. It will be appreciated that the center 422 is represented in FIG. 4 by a black dot, although no such dot would actually appear at a center of the ring-shaped interference pattern 402.

[0048] FIG. 5 illustrates a captured image 500 of the ring-shaped interference pattern 402 projected on a face 502, which is an example of a body on which the ring-shaped interference pattern 402 may be projected to identify a distance to the object and / or to identify the object, as described further below. In implementations, the image processing subsystem 122 (see FIG. 1 ) is configured to identify points 504 that are illuminated at equivalent magnitude. By exploiting the ring-shaped interference pattern 402 and identifying the resulting, regular pattern of magnitudes that the ring-shaped interference pattern 402 projects, without using a specialized dot-pattern or fringe projector, the image processing subsystem 122 can identify distinct points on the face 502 or other object to be able to identify distances to or other attributes of the face 502 or object.

[0049] FIG. 6 illustrates an example method 600 of generating illumination including a ringshaped interference that can be used to measure distances to objects as described further below. At a block 602, light is generated that includes at least substantially coherent light from a light source, as described with reference to FIGS. 1 and 3. At a block 604, the at least substantially coherent light is received at a proximal side of a body that is at least partially-transparent to the at least substantially coherent light, as described with reference to FIG. 3. At a block 606, a first portion of photons of the at least substantially coherent light is transmitted from the proximal side of the body through a distal side of the body as described with reference to FIG. 3. At a block 608, a second portion of photons of the at least substantially coherent light is reflected between internal surfaces of the body at the distal side and the proximal side to shift a phase of the second portion of photons before transmitting the second portion of photons through the distal side, thefirst portion of photons and the second portion of photons of the at least substantially coherent light interfering with each other to generate illumination having a ring-shaped interference pattern, as described with reference to FIGS. 3 and 4.EXAMPLE OF MEASURING DISTANCES USING THE RING-BASED INTERFERENCE PATTERN

[0050] Distances to objects may be measured in different ways taking advantage of the ringshaped interference pattern 402 that is included in illumination 400 (see FIG. 4) generated by passing light generated by the light source 108 through the body 102.

[0051] FIG. 7 shows a top-down view of an example in which triangulation is used to measure a distance between the body 102 (see FIG. 1) and points on an object 700. The light source 108 generates the illumination 400 (see FIG. 4) including the ring-shaped interference pattern 402 (see FIG. 4) that, after being reflected and scattered by the object 700, is detected by the sensor 118 (see FIG. 1). The sensor 118 is configured to identify rings of one or more orders of magnitude that may be used to differentiate between aspects of the object 700 being illuminated, whether the rings include the rings of highest magnitude 406 (see FIG. 4) and that of the rings of lowest magnitude 408 (see FIG. 4), or rings of another selected magnitude.

[0052] The illumination generated includes a plurality of beams including a perpendicular beam 702 that is generated at a perpendicular angle 704 to the light source 108 and a beam 706 that is generated at an angle 0 708 relative to the perpendicular beam 702. The perpendicular angle 704 and the angle 0 708 may be regarded as the angular coordinates of point cO 710 and point cl 712 within rings of the selected order of magnitude. The beams 702 and 706 illuminate points cO 710 and cl 712 on the object 700. In implementations, the points cO 710 and cl 712, are selected for measurement because reflected beams 714 and 716, which are reflected from the points cO 710 and cl 712 are within a ring of selected order of magnitude within the ring-shapedinterference pattern 402, whether the selected order of magnitude includes the rings of highest magnitude 406 and that of the rings of lowest magnitude 408, or rings of another selected magnitude.

[0053] A distance D 718 from a plane 720 of the body 102 to a reference plane 722, which includes the point cO 710, represents both a distance to the point cO 710 and a distance which may be used as a reference distance to measure distances to other points such as point cl 712. Distances from the plane 720 of the body 102 to other points, such as an additional distance d 724 from the reference plane 722 to an additional plane 726 including the point cl 712 also may be measured using triangulation. A baseline distance L 728 from a centerline 730 of the light source 108 to a centerline 732 of the lens 120 (see FIG. 1) or other input of the sensor 118 may provide a baseline to measure other distances used in triangulating distances. For example, a distance aO 734 from the centerline 732 to a point at which the reflected beam 714 is received at a focal plane 736 and a distance al 738 from the centerline 732 of the lens 120 to a point at which the reflected beam 716 is received at the focal plane 736. The focal plane 736 is at a focal distance f 740 from the plane 720 of the body 102.

[0054] The formulae used to triangulate the distances are derived using geometry and are provided in Eqs. (1) through (4). Eq. (1) shows the relationship between measured and known quantities described with reference to FIG. 7 to determine the distance D 718 from the plane 720 of the body 102 to the reference plane 722 including the point cO 710:a0 / f= L / D (1)

[0055] Using algebra, Eq. (1) can be rewritten as Eq. (2) to solve for the quantity of interest, the distance D 718:D = (f / a0) L (2)

[0056] Eq. (3) shows the relationship between the distance d 724 representing the additional distance to the plane 726 including the point cl 712 which can be determined using trigonometry7:al / f = ((D + d)tan 0 - L) / (D + d) (3)

[0057] Using algebra, Eq. (3) can be rewritten as Eq. (4) to solve for the quantity of interest, the distance d 724:d = L / ((tan 0 - (al / f)) - D (4)

[0058] Thus, using the system of FIG. 7, by knowing and / or measuring the quantities 0708, L 728, aO 734, al 738, and f 736, distances D 718 and d 724 can be calculated to determine distances to points such as cO 710 and cl 712 on the object 700. Interpolation may be used to determine distances to other points, such as point c2 742, situated between points cO 710 and cl 712. Extrapolation may be used to determine distances to other points not located between points to which the distance has been determined, such as point c3 742 which is not between points cO 710 and cl 712. By measuring reflected light from the illumination 400 including the ring-shaped interference pattern 402, the distance to any number of points on the object 700 may be determined. As a result, a depth map of the object 700 may be determined that may be used for object identification.

[0059] Referring to FIG. 8. when an obj ect includes a human face 800. distances to a number of points 802 and 804 across a width 806 and height 808, respectively, of the face 800 may be determined as previously described to develop a depth map 810 of the face 800. Although only two columns of points 802 and 804 are shown in FIG. 8. it will be appreciated that distances to any number of points in any number of rows and / or columns on the face, or any number of points at any positions on the face 800, may be measured to generate a depth map of the face 800 or another object to a desirable degree of accuracy.

[0060] Referring to FIG. 9, for user authentication or other image recognition applications, once a depth map of the human face 800 (see FIG. 8) or other object has been derived, it may be compared to a previously generated depth map 900 of a human face of an authorized user 902. The sets of points 802 and 804 (see FIG. 8) in the generated depth map 810 may be compared to corresponding sets of points 904 and 906 in corresponding positions on the human face of the authorized user 902 on the previously-generated depth map 900. In implementations, if a sufficient number of the points 802 and 804 on the generated depth map 810 match within a selected margin of error with the points 904 and 906 on the previously-generated depth map 900, the human face 800 represented by the generated depth map 810 may be considered a match with the previously -generated depth map 900. It will be appreciated that the system and techniques used to generate the depth map 810 may also be used to generate the previously generated depth map 900 from which a user subsequently may be authenticated.

[0061] FIG. 10 illustrates an example method 1000 of measuring distances to objects and generating a depth map for the object. At a block 1002, a ring-shaped interference pattern is detected, including detecting one or more rings of one or more desired orders of magnitude as described with reference to FIG. 4. At a block 1004, angular coordinates are associated with the one or more rings of the selected one or more orders of magnitude, as also described with reference to FIG. 3. At a block 1006, imaging data is captured. As described with reference to FIG. 7, the imaging data may include positions of points in the image data that may be used in performing triangulation of the image data to determine distances to points of interest. For example, as described with reference to FIG. 7, the distances aO 734 and al 738 may be used to determine distances to points cO 710 and cl 712, respectively.

[0062] At a block 1008, triangulation is used to determine distance to or depth of points on an object that intersect with the rings of selected magnitude as described with reference to FIG. 7.At a block 1010, interpolation and / or extrapolation may be used to determine distances to additional points on the surface of the object. Interpolation and / or extrapolation may be used to determine the distances to additional points either between or around points within rings of the desired order of magnitude for which triangulation is used to measure the distance. At a block 1012, a depth map is generated for the surface of the object using the measured and / or interpolated / extrapolated distances.

[0063] Whilst the above embodiments use the magnitude of rings and rings of one or more the desired orders of magnitude, other attributes might be used instead, such as the presence of a type of ring and other ring-related attributes.APPLYING MACHINE LEARNING TO IDENTIFY CAPTURED DATA ILLUMINATED WITH RING-SHAPED INTERFERENCE PATTERN

[0064] Instead of using triangulation, distances to objects may also be determined by using machine learning to compared image data captured with illumination including the ring-shaped interference pattern with training data generated using the ring-shaped interference data. Machine learning, in general, is software that is not programmed to literally respond to specific data inputs, but includes software that is configured to respond to multiple categories of inputs, to assign likelihoods and weights to w hat each of those inputs suggest, and then reach an overall conclusion as to whether it is more likely than not that the given inputs support reaching one conclusion or another.

[0065] In this way, machine learning seeks to mimic how neurons of a human mind process information. For example, upon seeing an animal, a human mind may seek to differentiate what type of animal it is based on the size of the animal, how many legs it has, whether it has a tail, whether it has fur, the length of the fur, the color of the fur, the shape of the head, the size of the ears, and other attributes. None of these attributes may singularly or definitively indicate whattype of animal it is, but combining certainty as to which of these characteristics might indicate may ultimately determine whether an animal is a rabbit, a dog, a cat, a monkey, a human, etc.

[0066] In implementations, machine learning may be applied by using a neural network to identity' aspects in the image data that indicate distances to those aspects. Referring to FIG. 11, a trained machine-learned model, such as a neural network 1100 may include a plurality of input neurons or nodes II 1102, 12 1104, 13 1106, and 14 1108 that, in turn, are associated with one or more layers each including a plurality of intermediate or hidden nodes Hl 1110, H2 1112, H3 1 114, H4 11 16, and H5 1 118. Ultimately, the hidden nodes Hl 11 10, H2 1112, H3 1114, H4 1 116, and H5 1118 are associated with a plurality of output nodes 01 1120, 02 1122, and 03 1124. Each of the nodes or neurons is associated mathematically with the nodes that feed into it with a weighted mathematical relationship. The output of each of the nodes is based on whether each of the inputs reaches a predetermined threshold value and, if the input reaches the predetermined threshold value, a predetermined weight is applied to that outcome. In turn, an output of that node is based on the weighted combination of each of the inputs that have reached the predetermined threshold value.

[0067] In image processing, input nodes are typically associated with each of a number of identifiable aspects of the image data input to the neural network. For example, in image processing used for number recognition, input nodes may be established for attributes such as lower loops that may be used in sixes or eights, upper loops that may be used in eights or nines, and various tails that may be used on the bottoms of twos, sixes or sevens or nines, etc. Each of the input nodes may include a threshold for whether these attributes are detected and a weight that is representative of how likely the identified attribute represents indicia of a particular number. Hidden nodes may then respond to combinations of the attributes detected by the input nodes to indicate whether the combination of attributes represents a particular number. Ultimately, basedon evaluating the outputs of the hidden nodes, the output nodes indicate whether a particular numeral is identified. Neural networks may be coded in various programming languages including Python, Java, or any number of programming languages. Alternatively, specialized coding platforms such as Keras, Py Torch, or other neural network creation platforms may be used to develop a neural network.

[0068] In the neural network 1100, for the sake of illustration, a number of input nodes II 1102, 12 1104, 13 1106, and 14 1108 may be selected to respond to input image data 1126, such as the magnitude of the rings resulting from the ring-shaped interference pattern. Hidden nodes Hl 1110, H2 1 112, H3 1114, H4 1116, and H5 1118 may be configured to respond to a relative size of portions of the rings, a separation of the portions of the rings, and other factors. Ultimately, output nodes 01 110, 02 1122, and 03 1124 may indicate whether aspects of a particular object are nearby, far away, or at some intermediate distance.

[0069] FIG. 12 illustrates sets of reference data 1200, 1202, 1204, 1206, and 1208 that may be used to determine threshold and weighting parameters to “train” or tune the neural network 1100 to recognize faces. The sets of reference data 1200, 1202. 1204, 1206, and 1208 may be captured by the imaging system and represent reference scenes that are known or that have been empirically measured so that it is known what the desired image processing results are for the sets of reference data 1200. 1202, 1204, 1206, and 1208. Thus, the sets of reference data 1200. 1202, 1204, 1206, and 1208 include data in which illumination 400 includes the ring-shaped interference pattern 402 (see FIG. 4) that is reflected and scattered by objects included in the reference scene. The sets of reference data 1200, 1202, 1204, 1206, and 1208 are processed to generate depth maps for objects in the reference scenes, such as the depth map 1210 that includes depth data 1212 for a human face 1214 in the reference data 1200. The parameters of the neural network 1100 maythen be set so that the neural network 900 provides outputs that match the known conditions represented in the sets of training data 1200, 1202, 1204, 1206, and 1208.

[0070] For example, a first set of reference data 1200 includes the face human 1214 that is relatively close by, as indicated by a relative size of the face 1214 being shown as fairly large. A second set of reference data 1202 includes a human face 1216 that is further away and, thus, appears to be smaller. Although the faces 1214 and 1216 are presented at different sizes to model faces seen at different distances, the faces 1214 and 1216 are otherwise the same; accordingly, the neural network 1 100 (see FIG. 11 ) should be tuned to yield a same result for both sets of reference data 1200 and 1202 in order to authenticate the faces 1214 and 1216 as they appear in either represented case.

[0071] On the other hand, a third set of reference data 1204 shows a different human face 1218 that should not be authenticated by the neural network 1100. Similarly, although the fourth set of reference data 1206 and a fifth set of reference data 1208 include facsimiles of a same human face as the face 1214 and 1216, they are not actually the same face. The fourth set of reference data 1206 includes a photograph 1220 of a same human face 1222 as the human face 1214 and 1216 to “spoof the face 1214 and 1216. The neural network 1100 desirably should be trained so as to refuse to authenticate a user based on the photograph 1220 being presented. Similarly, the fifth set of reference data 1208 includes a synthetic copy 1224, such as a mask or model (as represented in FIG. 12 by an outline of the human face 1214 or 1216) appearing in dotted lines in FIG. 12) of the human face 1214 and 1216 in another attempt to spoof the human face 1214 and 1216. Unlike the two-dimensional photograph 1220, the synthetic copy 1224 is three-dimensional, which may make it more difficult to differentiate from the human face 1214 and 1216. Nonetheless, the reflected illumination from the synthetic copy 1224 may present a different contrast or the reflected illumination may present a different correlation width than thehuman face 1214 and 1216 to enable differentiation of the synthetic copy 1224 (e.g., a mask) from the human face 1214 and 1216.

[0072] Reference data such as the sets 1200, 1202, 1204, 1206, 1208, and other sets of reference or training data and associated depth maps, such as the depth map 1210, thus may be used to set thresholds and weights used in the nodes of the neural network 900 or another machine-learned model to train and / or tune the neural network 900. Using the reference data enables the neural network 900 or another machine-learned model to properly evaluate distances to objects, such as human faces, in subsequently captured image data in order to determine distances objects.

[0073] FIG. 13 illustrates an example method 1300 of measuring distance to points on an object by analyzing reflections of light including the ring-shaped interference pattern. At a block 1302, illumination is generated that includes at least substantially coherent light. At a block 1304, the at least substantially coherent light is received at a proximal side of a body. At a block 1306, a first portion of photons of the at least substantially coherent light is transmitted from the proximal side of the body through a distal side of the body. At a block 1308, a second portion of photons of the at least substantially coherent light is reflected between internal surfaces of the body to shift a phase of the second portion of photons before transmitting the second portion of photons through the distal side, the first portion of photons and the second portion of photons of the at least substantially coherent light interfering with each other to generate illumination having a ring-shaped interference pattern. At a block 1310, a portion of the illumination reflected from an object is received. At a block 1312, the received portion of the illumination is analyzed to determine a distance from the body to a plurality’ of points of the object based on attributes of the ring-shaped interference pattern.

[0074] FIG. 14 illustrates an example method 1400 of using a machine-learned model, such as the neural network 900, to generate depth data for an object imaged by the imaging subsystem106. At a block 1402, reference data is captured including the ring-shaped interference pattern reflected and scattered by reference scenes being imaged. At a block 1404, depth maps are generated for the reference scenes. At a block 1406, the depth maps are used to train the machine-learned model to determine depth of objects in the reference scenes. At a block 1408, with the machine-learned model trained as previously described, interference imaging data reflected and scattered by scene being imaged is captured. At a block 1410, captured interference imaging data is submitted to the trained machine-learned model. At a block 1412, depth data is generated for captured interference imaging data based on machine-learned model comparison to training data.

[0075] FIG. 15 illustrates another example method 1500 of using a machine-learned model, such as the neural network 900, to differentiate between actual and spoofed human faces. At a block 1502, reference data is captured including the ring-shaped interference pattern reflected and scattered by reference scenes including actual human faces. At a block 1504, imaging reference data is captured that includes illumination including the ring-shaped interference pattern reflected and scattered by two-dimensional or three-dimensional spoofs of human faces, such as those described with reference to FIG. 12. At ablock 1506, captured interference imaging data of actual and spoofed human faces is used to train a machine-learned model such as the neural network of FIG. 11 to differentiate between actual and spoofed human faces based on interference imagine reference data. At a block 1508, with the machine-learned model trained as previously described, interference imaging data reflected and scattered by a face being imaged is captured. At a block 1510, captured interference imaging data is submitted to the trained machine-learned model. At a block 1512, the face included in the captured imaging data is classified as an actual human face or a spoofed human face.EXAMPLE DEVICES OPERABLE TO ADJUST GRAY LEVELS AT LOW LUMINANCE LEVELS

[0076] FIG. 16 is ablock diagram of an example implementation 1600 of electronic devices 1602 that are operable to use illumination including the ring-shaped interference pattern. For example, the electronic devices 1602 operable to use illumination including the ring-shaped interference pattern may include a smartwatch 1602-1, a mobile telephone 1602-2, a flat panel computing system 1602-3 (e.g., a tablet computer, an automotive display, etc.), a portable computing system 1602-4, a desktop computing system with an associated monitor 1602-5, a video monitor 1602-6 (e.g., a television, another video monitor, etc.), augmented reality (AR) glasses (e.g., AR glasses) 1602-7, and virtual reality' (VR) glasses or goggles (e.g., VR glasses or goggles) 1602-8. It will be appreciated that the example electronic devices 1602 are just that -examples of electronic devices that are operable to use illumination including the ring-shaped interference pattern. Any other electronic device with a display may also be used with implementations herein described to use illumination including the ring-shaped interference pattern.

[0077] As illustrated in FIG. 16, an electronic device 1602 includes hardware and / or software components to generate and use illumination including the ring-shaped interference pattern. The electronic device 1602 may be implemented in a system-on-chip (SOC) device or on one or more printed circuit boards (PCBs) or may otherwise be configured to support the functions described herein. In implementations, the electronic device 1602 includes one or more processors 1604 to process computer-executable instructions and respond to data that may be stored in computer-readable media 1606. The computer-readable media 1606 may include a combination of random-access memory (RAM), read-only memory (ROM), one-time programmable (OTP) memory, flash memory, or any other type of memory or storage device operable to maintain instructions and data. The instructions and data stored in the computer-readable media 1606 mayinclude an operating system 1608, one or more applications 1610, and an imaging manager 1612 that is configured to capture and process image data of scenes including faces or other objects.

[0078] In aspects, the imaging manager 1612 interacts with an imaging subsystem, such as the imaging subsystem 106 (see FIG. 1). The imaging subsystem 1614 includes a light source 1616 such as the light source 108 (see FIG. 1) that is configured to generate at least substantially coherent light through an at least partially-transparent body to generate the ring-shaped interference pattern. The imaging subsystem 1614 also includes an image processing subsystem 1620 such as the image processing subsystem 122 (see FIG. 1).

[0079] Thus, FIG. 16 shows articles of manufacture, including one or more electronic devices 1602-1 through 1602-8 that include one or more non-transitory computer-readable media 1606 having stored thereon program instructions stored in the computer-readable media 1606 that, upon execution by the processor 1604 of one of the electronic devices 1602-1 through 1602-8, perform any of the methods described herein, including the methods described with reference to FIGS. 6, 10, and 13-15. Similarly, FIG. 16 shows computer-readable media, such as the computer-readable media 1606, having stored thereon program instructions that, upon execution by the processor 1604, causes the processor 1604 of an electronic device, such as the electronic devices 1602-1 through 1602-8, to perform any of the methods described herein, including the methods described herein, including the methods described with reference to FIGS. 6, 10, and 13-15.

[0080] Unless context dictates otherwise, use herein of the word “or’' may be considered use of an “inclusive or,” or a term that permits inclusion or application of one or more items that are linked by the word “or” (e.g., a phrase “A or B” may be interpreted as permitting just “A,” as permitting j ust “B,” or as permitting both “A" and “B”). Also, as used herein, a phrase referring to “at least one of’ a list of items refers to any combination of those items, including single members. For instance, “at least one of a, b, or c” can cover a, b, c, a-b, a-c, b-c, and a-b-c, aswell as any combination with multiples of the same element (e.g., a-a, a- a- a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c, or any other ordering of a, b, and c). Further, items represented in the accompanying figures and terms discussed herein may be indicative of one or more items or terms, and thus reference may be made interchangeably to single or plural forms of the items and terms in this written description.ADDITIONAL EXAMPLES

[0081] In the following section, additional examples are provided:

[0082] Example 1 : A system includes a light source configured to generate light, including that is at least substantially coherent light, and a body that is at least partially -transparent to the at least substantially coherent light and configured to: receive the at least substantially coherent light at a proximal side of the body, transmit a first portion of photons of the at least substantially coherent light from the proximal side of the body through a distal side of the body, and reflect a second portion of photons of the at least substantially coherent light between internal surfaces of the body at the distal side and the proximal side to shift a phase of the second portion of photons before transmitting the second portion of photons through the distal side, the first portion of photons and the second portion of photons of the at least substantially coherent light interfering with each other to generate illumination having a ring-shaped interference pattern.

[0083] Example 2: The system of Example 1. wherein the light source is configured to generate the light outside of a human-visible spectrum.

[0084] Example 3: The system of Example 1, wherein the light source includes one of a laser or another coherent light source.

[0085] Example 4: The system of any of the preceding Examples 1 or 2, wherein the body includes a display screen of an electronic device that includes one or more regions that are at leastpartially-transparent to the at least substantially coherent light to transmit the first portion of photons and the second portion photons of the at least substantially coherent light and to receive the illumination reflected from the object.

[0086] Example 5 : The system of any one of the preceding Examples, wherein the display screen includes a plurality of layers including wherein the body display screen includes a glass layer that is at least partially-transparent to the at least substantially coherent light a plurality of layers including beneath a display glass layer and additional layers including one or more of a polarizing layer, a color filter layer, a liquid crystal display layer, an anode layer, an organic emitter layer, and a cathode layer.

[0087] Example 6: The system of any of the preceding Examples, further comprising an image processing subsystem configured to receive and analyze a portion of the illumination reflected from a plurality of points on an object, to determine a distance from the body to the plurality of points of the object based on attributes of the ring-shaped interference pattern.

[0088] Example 7: The system of any one of the preceding Examples, wherein the image processing subsystem is configured to identity’ the plurality of points within at least one of peaks or troughs in the ring-shaped interference pattern included in the illumination reflected from the object.

[0089] Example 8: The system of any one of the preceding Examples, wherein the image processing subsystem is configured to use triangulation to determine the distance from the body to the plurality of points of the object.

[0090] Example 9: The system of any one of the preceding Examples, wherein the distance from the body to the plurality of points on of the object is used to generate a depth map of the object.

[0091] Example 10: The system of any one of the preceding Examples, wherein the image processing subsystem is configured to use a machine-learned model to compare the plurality of points to training data to determine the distance from the body to the plurality of points of the object.

[0092] Example 11: The system of Example 10, wherein the object includes a human face and the image processing subsystem is configured to compare the depth map of the object to a previously-generated depth map of a face of an authorized user to authenticate the human face as being the authorized user.

[0093] Example 12: The system of Example 11 , wherein when the object includes a human face, the machine-learned model is trained to differentiate the human face from a spoofed human face that includes one of an image of a human face or a synthetic copy of a human face.

[0094] Example 13: The system of Examples 10, 11, or 12, wherein when the machine-learned model includes a neural network.

[0095] Example 14: The system of any one of the preceding Examples, wherein the light source, the body, and the image processing subsystem are included in one of: a smartwatch, a mobile telephone, a flat panel computing system including a tablet computer or an automotive display, a portable computing system, a desktop computing system with an associated monitor, a video monitor or television, augmented reality glasses; and virtual reality glasses.

[0096] Example 15 : The system of any one of the preceding Examples, wherein the plurality of points of the object are on a surface of the object.

[0097] Example 16: The system of any one of the preceding Examples, wherein the attributes of the ring-shaped interference pattern comprise rings of one or more magnitudes.

[0098] Example 17: A method comprising generating illumination including at least substantially coherent light, receiving the at least substantially coherent light at a proximal side ofa body, transmitting a first portion of photons of the at least substantially coherent light from the proximal side of the body through a distal side of the body, reflecting a second portion of photons of the at least substantially coherent light between internal surfaces of the body to shift a phase of the second portion of photons before transmitting the second portion of photons through the distal side, the first portion of photons and the second portion of photons of the at least substantially coherent light interfering with each other to generate illumination having a ring-shaped interference pattern, receiving a portion of the illumination reflected from an object, and analyzing the received portion to determine a distance from the body to a plurality of points of the object based on attributes of the ring-shaped interference pattern.

[0099] Example 18: The method of Example 17, using the system of any one of Examples 1 to 16.

[0100] Example 19: An article of manufacture including one or more non-transitory computer-readable media, having stored thereon program instructions that, upon execution by a processor of an electronic device, cause the electronic device to perform the method of Examples 17 or 18.

[0101] Example 20: A computer-readable medium including computer-executable instructions stored thereon to cause a processor of an electronic device to perform the method of Examples 17 or 18.CONCLUSION

[0102] Although implementations of systems and techniques for implementing a depth camera using display -induced interference pattern illumination have been described in language specific to certain features and / or methods, the subject of the appended claims is not necessarily limited to the specific features or methods described. Rather, the specific features and methodsare disclosed as example implementations of systems and techniques for implementing a depth camera using display -induced interference pattern illumination.

Claims

CLAIMSWhat is claimed is:

1. A system comprising:a light source configured to generate light, including at least substantially coherent light; anda body that is at least partially -transparent to the at least substantially coherent light and configured to:receive the at least substantially coherent light at a proximal side of the body; transmit a first portion of photons of the at least substantially coherent light from the proximal side of the body through a distal side of the body; andreflect a second portion of photons of the at least substantially coherent light between internal surfaces of the body to shift a phase of the second portion of photons before transmitting the second portion of photons through the distal side, the first portion of photons and the second portion of photons of the at least substantially coherent light interfering with each other to generate illumination having a ring-shaped interference pattern.

2. The system of claim 1, wherein the light source is configured to generate the light outside of a human-visible spectrum.

3. The system of claim 1, wherein the light source includes one of a laser or another coherent light source.

4. The system of any one of the preceding claims, wherein the body includes a display screen of an electronic device that includes one or more regions that are at least partially -transparent to the at least substantially coherent light to transmit the first portion of photons and the second portion photons of the at least substantially coherent light and to receive the illumination reflected from an object.

5. The system of any one of the preceding claims, wherein the body display screen includes:a glass layer that is at least partially-transparent to the at least substantially coherent light a plurality of layers including beneath a display glass layer; andadditional layers including one or more of a polarizing layer, a color filter layer, a liquid crystal display layer, an anode layer, an organic emitter layer, and a cathode layer.

6. The system of any one of the preceding claims, further comprisingan image processing subsystem configured to receive and analyze a portion of the illumination reflected from a plurality of points on an object, to determine a distance from the body to the plurality of points of the object based on attributes of the ring-shaped interference pattern.

7. The system of any one of the preceding claims, wherein the image processing subsystem is configured to identify the plurality of points within at least one of peaks or troughs in the ringshaped interference pattern included in the illumination reflected from the object.

8. The system of any one of the preceding claims, wherein the image processing subsystem is configured to use triangulation to determine the distance from the body to the plurality7of points of the object.

9. The system of any one of the preceding claims, wherein the distance from the body to the plurality of points of the object is used to generate a depth map of the object.

10. The system of any one of the preceding claims, wherein the image processing subsystem is configured to use a machine-learned model to compare the plurality of points to training data to determine the distance from the body to the plurality of points of the object.

11. The system of claim 10, wherein the object includes a human face and the image processing subsystem is configured to compare the depth map of the object to a previously -generated depth map of a face of an authorized user to authenticate the human face as being the authorized user.

12. The system of claim 11. wherein when the object includes a human face, the machine-learned model is trained to differentiate the human face from a spoofed human face that includes one of an image of a human face or a synthetic copy of a human face.

13. The system of claims 10. 11, or 12, wherein the machine-learned model includes a neural network.

14. The system of any one of the preceding claims, wherein the light source, the body, and the image processing subsystem are included in one of:a smartwatch;a mobile telephone;a flat panel computing system including at least one of a tablet computer or an automotive display;a portable computing system;a desktop computing system with an associated monitor;a video monitor or television;augmented reality glasses; andvirtual reality glasses.

15. The system of any one of the preceding claims, wherein the plurality of points of the object are on a surface of the object.

16. The system of any one of the preceding claims, wherein the attributes of the ring-shaped interference pattern comprise rings of one or more orders of magnitude.

17. A method comprising:generating illumination including at least substantially coherent light;receiving the at least substantially coherent light at a proximal side of a body; transmitting a first portion of photons of the at least substantially coherent light from the proximal side of the body through a distal side of the body;reflecting a second portion of photons of the at least substantially coherent light between internal surfaces of the body to shift a phase of the second portion of photons before transmitting the second portion of photons through the distal side, the first portion of photons and the second portion of photons of the at least substantially coherent light interfering with each other to generate illumination having a ring-shaped interference pattern;receiving a portion of the illumination reflected from an object; andanalyzing the received portion to determine a distance from the body to a plurality of points of the object based on attributes of the ring-shaped interference pattern.

18. The method of claim 17, using the system of any one of claims 1 to 16.

19. An article of manufacture including one or more non-transitory computer-readable media, having stored thereon program instructions that, upon execution by a processor of an electronic device, cause the electronic device to perform the method of claims 17 or 18.

20. A computer readable medium including program instructions stored thereon to cause a processor of an electronic device to perform the method of claims 17 or 18.

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