Surface quality sensing using self-mixing interferometry

Abstract

The present disclosure relates to surface quality sensing using self-mixing interferometry. The present invention describes an electronic device. The electronic device includes a housing, a set of one or more SMI sensors attached to the housing, and a processor. The set of one or more SMI sensors includes a set of one or more electromagnetic radiation emitters, the set of one or more electromagnetic radiation emitters having a set of one or more resonant cavities and configured to emit a set of one or more electromagnetic radiation beams. The set of one or more SMI sensors also includes a set of one or more detectors, the set of one or more detectors configured to generate an indication of self-mixing within the set of one or more resonant cavities. The processor is configured to use the indication of self-mixing to characterize the light field speckle of the target. The processor is also configured to use the characterization of the light field speckle to characterize the surface quality of the target.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a non-provisional application of U.S. Provisional Patent Application No. 63 / 083,431 filed on September 25, 2020, and claims the benefit of the U.S. Provisional Patent Application No. 63 / 083,431 under 35 U.S.C. §119(e), the contents of which are incorporated herein by reference as if fully disclosed herein. Technical Field

[0003] The described embodiments relate generally to sensing of surface quality and, more particularly, to sensing of surface quality using self-mixing interferometry. Background Art

[0004] Surface qualities such as roughness and waviness play a key role in a person's physical interaction with and perception of real-world objects. For example, an object with a rougher surface can generate greater friction when a person touches, feels, or grasps an object. When trying to understand the surface quality of an object, a person can drag their fingers along the surface of the object. This can stimulate (e.g., vibrate) a large number of tactile receptors in a person's fingers and give a person a good idea of ​​whether a surface is rough or undulating, and how rough or undulating it is. When grasping an object, a certain amount of roughness can make it easier to grasp the object, but too much roughness can cause pain and make it more difficult to grasp the object. When a person paints, draws, or writes on a rougher surface, some brushes, pens, or pencils (especially those with softer or more flexible tips) can generate heavier strokes or strokes with more diffuse edges. When visible light passes through or is redirected from a smooth surface, an observer may be able to discern that the transmitted light or the redirected light has a specular response, which in turn can help the observer recognize that the surface is smooth. When visible light passes through or is redirected from a rough surface, an observer may be able to discern that the transmitted or redirected light has a diffuse response, which in turn may help the observer recognize that the surface is rough.

[0005] In order for a machine to better understand an object it images or contacts, the machine should conceptually know or be able to determine the surface quality of the object. When the machine knows the surface quality of an object, the machine can better represent the object on a display, model the interaction of a person or other (real or virtual) object with the object (e.g., in an augmented reality (AR) or virtual reality (VR) environment), describe or reconstruct the surface quality for a person who has not yet physically interacted with the object (e.g., via tactile, electrostatic, thermal, and / or other types of actuators), etc.

[0006] Existing surface texture measurement systems may include, for example, a mechanical stylus profilometer, a white light interferometer profilometer (a type of image-based interferometer profilometer), a laser confocal profilometer, and the like. Summary of the invention

[0007] Embodiments of the systems, devices, methods, and apparatus described in the present disclosure use self-mixing interferometry (SMI) to sense surface quality. The embodiments may include, for example, a single SMI sensor; a set of multiple SMI sensors having different incident angles, numerical apertures, working distances, polarizations, and / or wavelengths of emitted electromagnetic radiation; or one or more SMI sensors that emit and / or receive electromagnetic radiation through a tunable set of optical devices.

[0008] An SMI sensor is defined herein as a sensor configured to: generate electromagnetic radiation (e.g., light); emit electromagnetic radiation from a resonant cavity (e.g., a resonant optical cavity); receive a return portion of the electromagnetic radiation back into the resonant cavity (e.g., electromagnetic radiation reflected or scattered from a surface); coherently or partially coherently self-mix the generated and returned electromagnetic radiation within the resonant cavity; and produce an output indicative of the self-mixing (i.e., an SMI signal). The generated, emitted, and returned electromagnetic radiation may be coherent or partially coherent. In some examples, the electromagnetic radiation emitted by the SMI sensor may be generated by an electromagnetic radiation source such as a laser (e.g., a vertical cavity surface emitting laser (VCSEL), a vertical external cavity surface emitting laser (VECSEL), a quantum dot laser (QDL), a quantum cascade laser (QCL), an edge emitting laser (EEL), a horizontal cavity surface emitting laser (HCSEL), a solid-state laser (SSL), or a gas laser) or a light emitting diode (LED) (e.g., an organic LED (OLED), a resonant cavity LED (RC-LED), a micro-LED (mLED), a superluminescent LED (SLED), or an edge emitting LED). The generated, emitted, and returned electromagnetic radiation may include, for example, visible or invisible light (e.g., green light, red light, infrared (IR) light, ultraviolet (UV) light, etc.). The output of the SMI sensor (i.e., the SMI signal) may include a photocurrent generated by a photodetector (e.g., a photodiode) that is integrated with the electromagnetic radiation source of the sensor or positioned below, above, or beside the electromagnetic radiation source of the sensor. Alternatively or additionally, the output of the SMI sensor may include a measurement of the current or junction voltage of an electromagnetic radiation source of the SMI sensor.

[0009] In a first aspect, the present disclosure describes an electronic device. The electronic device may include a housing, a set of one or more SMI sensors attached to the housing, and a processor. The set of one or more SMI sensors may include a set of one or more electromagnetic radiation emitters, the set of one or more electromagnetic radiation emitters having a set of one or more resonant cavities and configured to emit a set of one or more electromagnetic radiation beams. The set of one or more SMI sensors may also include a set of one or more detectors, the set of one or more detectors configured to generate an indication of self-mixing within a set of one or more resonant cavities. The processor may be configured to characterize the light field speckle of the target using the indication of self-mixing. The processor may also be configured to characterize the surface quality of the target using the characterization of the light field speckle.

[0010] In a second aspect, the present disclosure describes a method. The method may include: receiving an indication of self-mixing from a set of one or more SMI sensors; determining at least one of a range or a directional velocity relative to a target using the indication of self-mixing; characterizing a light field speckle of the target using the indication of self-mixing and at least one of the range or the directional velocity; and characterizing a surface quality of the target using the characterization of the light field speckle.

[0011] In a third aspect, a method of characterizing surface quality is described. The method may include: receiving an indication of self-mixing from a set of one or more SMI sensors; characterizing a light field speckle of an object using the indication of self-mixing; and characterizing a surface quality of the object using the characterization of the light field speckle.

[0012] In addition to the illustrative aspects and embodiments described, further aspects and embodiments will become apparent by reference to the drawings and by study of the following descriptions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals refer to like structural elements, and wherein:

[0014] Figure 1A An example of a stylus including a set of one or more SMI sensors is shown;

[0015] Figure 1B An example of a wearable device including a set of one or more SMI sensors is shown;

[0016] Figure 2A shows an exemplary elevation view of a surface having surface roughness and surface waviness;

[0017] Figure 2B Shows Figure 2A exemplary graphs of surface roughness and surface waviness of the illustrated surfaces;

[0018] Figure 2C An exemplary lateral data distribution is shown from which the lateral data distribution can be determined. Figure 2A lateral correlation of the surface texture of the surfaces shown;

[0019] Figure 3 An exemplary SMI sensor is shown;

[0020] Figure 4A An exemplary array of SMI sensors is shown in relation to a surface of a target;

[0021] Figure 4B An exemplary SMI sensor and a set of tunable optics are shown in relation to a surface of a target;

[0022] Figure 5 An exemplary method of characterizing surface quality is shown;

[0023] Figure 6 An exemplary method of operating an SMI sensor is shown;

[0024] Fig. 7A An exemplary light field speckle envelope is shown;

[0025] Figure 7B shows exemplary graphs of light field speckle contrast and light field speckle correlation;

[0026] Fig. 8A An exemplary relationship between light field speckle contrast and surface roughness is shown;

[0027] Figure 8B An exemplary relationship between light field speckle correlation and surface correlation length is shown;

[0028] Figure 8C An exemplary use of light field speckle properties for modeling angular reflectivity of a surface is shown;

[0029] Fig. 9 An exemplary transfer function for deriving surface quality characteristics from an indication of a diversity of light field speckle characteristics and SMI sensor parameters is shown;

[0030] Fig.10 A set of exemplary stroke types is shown;

[0031] Fig.11A and Fig. 11B showing an alternative animation of the virtual object, the animation being responsive to the surface quality of the object; and

[0032] Fig.12 An exemplary electrical block diagram of an electronic device is shown.

[0033] The use of cross-hatching or shading in the drawings is generally provided to clarify boundaries between adjacent elements and also to facilitate legibility of the drawings. Thus, the presence or absence of cross-hatching or shading does not express or indicate any preference or requirement for particular materials, material properties, element proportions, element sizes, commonality of similar illustrated elements, or any other characteristic, property, or attribute of any element shown in the drawings.

[0034] Furthermore, it should be understood that the proportions and sizes (relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, spacings, and positional relationships presented therebetween are provided in the accompanying drawings solely to facilitate understanding of the various embodiments described herein, and therefore may not necessarily be presented or illustrated to scale and are not intended to indicate any preference or requirement for the embodiments illustrated to exclude the embodiments described in conjunction therewith. DETAILED DESCRIPTION

[0035] Reference will now be made specifically to the representative embodiments shown in the accompanying drawings. It should be understood that the following description is not intended to limit the embodiments to a preferred embodiment. On the contrary, it is intended to cover alternatives, modifications and equivalent forms that may be included in the spirit and scope of the embodiments defined by the appended claims.

[0036] The following description relates to SMI-based surface quality sensing. Compared to existing mechanical surface profiling and / or image-based surface quality sensors, the embodiments may be smaller (more compact), consume less power, and operate at higher speeds, and in some cases may be compact enough to be incorporated into a device that can be comfortably held or worn (such as a stylus, glove, or ring). For example, a set of SMI sensors and a processing system coupled thereto may be incorporated into a stylus (or electronic pen, pencil, or brush) that can be used to write, draw, or paint on any surface while drawing a line quality (or stroke) on an associated electronic display, where the line quality (or stroke) corresponds to the surface quality (e.g., roughness or waviness) of the surface on which the user is writing, drawing, or painting. As another example, a set of SMI sensors and an associated processing system may be incorporated into a glove that can sense the surface quality of an object while the user of the glove navigates an AR or VR environment. More generally, a set of SMI sensors and a portion or all of the associated processing systems may be incorporated into any device that enables a machine (or computer) to sense the surface quality of a physical object. In some cases, the device may contact the object to sense the surface quality, but in some cases this is not required.

[0037] As described herein, an SMI sensor can generate an SMI signal that can be used (eg, analyzed) to characterize a statistical property (light field speckle). The statistical property (light field speckle) can then be used to characterize a physical property (surface quality).

[0038] The SMI-based surface quality sensor can provide higher spatial resolution and dynamic range than image-based surface quality sensors, and can be lower cost, consume less power, and simultaneously determine the position (e.g., distance, speed, etc.) of the device. The SMI-based surface quality sensor can also function in situations where a predetermined surface quality is not required (e.g., glass screens, specialty papers, etc.).

[0039] refer to Figure 1A-Figure 12 These and other systems, devices, methods, and apparatus are described. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these drawings is for illustrative purposes only and should not be construed as limiting.

[0040] Directional terms, such as "top", "bottom", "upper", "lower", "front", "rear", "above", "below", "above", "below", "left", "right", etc., are used with reference to the orientation of some components in some of the figures described below. Because components in various embodiments can be positioned in a plurality of different orientations, the directional terms are used for illustrative purposes only and are not limiting in any way. Directional terms are intended to be interpreted broadly and therefore should not be interpreted to exclude components oriented in different ways. In addition, as used herein, the phrase "at least one of" following a series of items in the items separated by the terms "and" or "or" is to modify the list as a whole, rather than to modify each member of the list. The phrase "at least one of" does not require selection of at least one of each of the listed items; rather, the phrase allows for the meaning of including at least one of any of the items in the items and / or at least one of any combination of the items and / or at least one of each of the items in the items. For example, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" each refers to only A, only B, or only C; any combination of A, B, and C; and / or one or more of each of A, B, and C. Similarly, it is understood that the order in which elements are presented for a combined or separate list provided herein should not be construed to limit the present disclosure to only the order provided.

[0041] Figure 1AAn example of a stylus 100 including a set of one or more SMI sensors 102 is shown. By way of example, the stylus 100 is shown as including a first SMI sensor 102-1, a second SMI sensor 102-2, and a third SMI sensor 102-3. The SMI sensors 102 may be attached to a housing 104. By way of example, the SMI sensors 102 are shown as being housed within the housing 104, and the SMI sensors 102 may emit and receive electromagnetic radiation through an outer surface 106 of the housing 104. In some cases, the SMI sensors 102 may be mounted directly to the housing 104. In other cases, the SMI sensors 102 may be mounted on a shared substrate or on a separate substrate, and the substrate may be attached to the housing 104. Alternatively, one or more of the SMI sensors 102 may be mounted on the outer surface 106 of the housing 104, or may extend through an opening in the outer surface 106 of the housing 104.

[0042] The SMI sensor 102 may emit and receive electromagnetic radiation 108 through the outer surface 106 of the housing 104 or through an opening in the housing 104. Alternatively, and when the SMI sensor 102 is mounted on the outer surface 106 of the housing or extends through an opening in the outer surface 106, the SMI sensor 102 may emit and receive electromagnetic radiation 108 without the electromagnetic radiation passing through the housing 104.

[0043] In some embodiments, the housing 104 may have a tip 110 that is optically transparent to at least the wavelength of electromagnetic radiation emitted by the SMI sensor 102. For example, the tip 110 may be visually transparent, or may be optically transparent but visually opaque to the electromagnetic radiation emitted by the SMI sensor 102. In some embodiments, the tip 110 may be formed of a different material than adjacent portions of the housing 104. In some embodiments, the tip 110 may be an integral extension of a main body portion 112 (i.e., the stylus body) of the housing 104. In some cases, the tip 110 may have a curved or arcuate outer profile, as shown. In other cases, the tip 110 may have a tapered outer profile that culminates at a point or around a flat end surface. The tip 110 may also have an approximately square profile, a faceted profile, or other profiles.

[0044] The set of one or more SMI sensors 102 may include a set of one or more electromagnetic radiation sources having a set of one or more resonant cavities. The set of one or more resonant cavities may be configured to emit a set of one or more electromagnetic radiation beams 108. The set of one or more SMI sensors 102 may also include a set of one or more detectors configured to generate an indication of self-mixing within the set of one or more resonant cavities. The self-mixing may be a coherent or partially coherent self-mixing of the generated electromagnetic radiation with a returned portion (e.g., a scattered or reflected portion) of the emitted electromagnetic radiation 108. In some embodiments, the electromagnetic radiation source may include one or more of a laser (e.g., a VCSEL, VECSEL, QDL, QCL, EEL, HCSEL, SSL, or gas laser) or an LED (e.g., an OLED, RC-LED, mLED, SLED, or edge-emitting LED), etc. The generated, emitted, and returned electromagnetic radiation may include, for example, visible light or invisible light (e.g., green light, red light, IR light, UV light, etc.). The detectors may include: one or more photodetectors (e.g., photodiodes) integral with or positioned below, above, or beside the electromagnetic radiation source of the SMI sensor; circuitry configured to measure an electrical parameter (e.g., current or junction voltage) of the electromagnetic radiation source of the SMI sensor; etc. The indication of self-mixing generated by a set of one or more detectors may include an electrical signal (referred to herein as an SMI signal) or a digitized sample of the SMI signal. Figure 3 An exemplary SMI sensor including a photodiode integrated with a VCSEL is shown in FIG.

[0045] The electromagnetic radiation beam 108 emitted by the SMI sensor 102 may be scattered or reflected off the target 114, and in some cases may be scattered or reflected off different surfaces or layers of the target 114. For example, depending on the optical transmittance of the outer surface 116 and one or more sub-surfaces 118 of the target 114 (e.g., the surface of a layer or object below the outer surface 116), some or all of the emitted electromagnetic radiation 108 may be scattered or reflected from the outer surface 116, and other portions of the emitted electromagnetic radiation 108 may be scattered or reflected from one or more sub-surfaces 118.

[0046] The outer surface 116 (or the subsurface 118 of the target 114) may have a surface quality, which may be defined in terms of surface roughness, surface waviness, refractive index, subsurface scattering, etc. When the electromagnetic radiation beam 108 emitted by the SMI sensor 102 is scattered or reflected off the target 114, and the returning portion of the electromagnetic radiation beam mixes with the electromagnetic radiation generated by the SMI sensor within the resonant cavity of the electromagnetic radiation source of the SMI sensor, the SMI signal generated by the SMI sensor 102 may include information about the surface quality. This information may be used to characterize the surface quality.

[0047] The processing system 120 (i.e., a system including at least one processor) may be disposed within the housing 104, in a remote device that communicates with the stylus 100 via a wired or wireless interface, or distributed between the stylus 100 and the remote device. The processing system 120 or one or more of its processors may be configured to characterize the light field speckle of the target 114. The light field speckle may be characterized using an indication of self-mixing generated by the SMI sensor 102, and in some cases, the light field speckle may be further characterized using a set of known relationships between the SMI sensor 102 and the tip 110, the output of the motion sensor 122, etc. The processing system 120 or one or more of its processors may also be configured to characterize the surface quality of the target 114. The surface quality may be characterized using a characterization of the light field speckle, and in some cases may be the quality of the outer surface 116 and / or the sub-surface 118 of the target 114.

[0048] In some embodiments, processing system 120 or one or more of its processors may also use the self-mixed indication to determine a spatial relationship between housing 104 (or stylus 100 or tip 110) and target 114, such as one or more of the following: a pose of housing 104 (or stylus 100 or tip 110) relative to target 114; a distance from housing 104 (or stylus 100 or tip 110) to target 114; or a speed of movement between housing 104 (or stylus 100 or tip 110) and target 114. The spatial relationship may be determined while characterizing light field speckle and / or characterizing the surface quality of target 114. Alternatively, the spatial relationship may be determined before or after characterizing light field speckle and / or characterizing the surface quality of target 114.

[0049] In some embodiments, stylus 100 may include motion sensor 122, which in some cases may take the form of one or more of an inertial sensor, one or more accelerometers, a gyroscope, etc. One or more outputs of motion sensor 122 may be used by processing system 120 or its processor in conjunction with or in lieu of self-mixed indications generated by a set of one or more SMI sensors 102 to determine the pose of housing 104 (or stylus 100 or tip 110) relative to target 114; the distance of housing 104 (or stylus 100 or tip 110) to target 114; or the speed of movement between housing 104 (or stylus 100 or tip 110) and target 114.

[0050] In some embodiments, stylus 100 may include one or more actuators 124, such as one or more tactile actuators and / or electrostatic actuators, for providing feedback to a user (or holder) of stylus 100. In some cases, feedback may be provided to the user in response to or at an intensity corresponding to a surface quality sensed using a set of SMI sensors 102 and processing system 120. Actuator 124 may provide feedback of the actuator in response to one or more actuation signals provided by processing system 120 or a processor thereof.

[0051] Figure 1BAn example of a wearable device 130 including a set of one or more SMI sensors 132 is shown. By way of example, the wearable device 130 is shown as a glove that includes a first subset of SMI sensors (e.g., a first SMI sensor 132-1, a second SMI sensor 132-2, and a third SMI sensor 132-3) and / or a second subset of SMI sensors (e.g., a fourth SMI sensor 132-4, a fifth SMI sensor 132-5, and a sixth SMI sensor 132-6). In alternative embodiments, the wearable device 130 may be one or more of a synthetic skin (e.g., fingertip skin), a ring, goggles or glasses, a helmet, a necklace, a belt, a shirt, etc. The SMI sensor 132 may be attached to a housing 134, which in some cases may define the outer surface of the wearable device 130 and be formed of fabric, plastic, and / or other materials. By way of example, the SMI sensor 132 is shown as being housed within the housing 134, and the SMI sensor 132 may emit and receive electromagnetic radiation through the housing 134 (e.g., through the outer surface 136 of the wearable device 130). In some cases, the SMI sensor 132 may be mounted directly to the housing 134. In other cases, the SMI sensor 132 may be mounted on a shared substrate (e.g., a flexible circuit substrate) or on a separate substrate, and the substrate may be attached to the housing 134. Alternatively, one or more of the SMI sensors 132 may be mounted on the outer surface 136 of the housing 134, or may extend through an opening in the outer surface 136 of the housing 134.

[0052] The SMI sensor 132 may emit and receive electromagnetic radiation 138 through the outer surface 136 of the housing 134 or through an opening in the housing 134. Alternatively, and when the SMI sensor 132 is mounted on the outer surface 136 of the housing 134 or extends through an opening in the outer surface 136, the SMI sensor 132 may emit and receive electromagnetic radiation 138 without the electromagnetic radiation passing through the housing 134.

[0053] In some embodiments, the housing 134 can have one or more portions 140 that are optically transparent to at least the wavelength of electromagnetic radiation emitted by the SMI sensor 132. For example, the portion 140 can be visually transparent, or can be optically transparent but visually opaque to the electromagnetic radiation emitted by the SMI sensor 132. In some embodiments, the portion 140 can be formed of a different material than adjacent portions of the housing 134. In some embodiments, the portion 140 can be an integral extension of the main body portion 142 of the housing 134.

[0054] A set of one or more SMI sensors 132 may be associated with a reference Figure 1AThe SMI sensor is similarly configured and can provide an indication of self-mixing to a processing system 150 including one or more processors, as shown in FIG. Figure 1A The processing system 150 or one or more of its processors may be configured to characterize the surface quality of the target (e.g., the surface quality of the outer surface 146 and / or the sub-surface 148 of the target 144; or the surface quality of the user's skin inside the wearable device 130). The processing system 150 or one or more of its processors may also be configured or alternatively configured to use one or more outputs of the self-mixed indication and / or motion sensor 156 to determine the spatial relationship between the housing 134 (or the wearable device 130 or portion 140) and the target 144 (or the spatial relationship between the inner surface of the housing 134 and its user).

[0055] The wearable device 130 may include a first subset of SMI sensors 132-1, 132-2, 132-3, a second subset of SMI sensors 132-4, 132-5, 132-6, and / or other subsets of SMI sensors. The first subset of SMI sensors may emit a beam of electromagnetic radiation outward from the outer surface 136 of the wearable device 130 (i.e., away from the user (or wearer) of the wearable device 130). For example, the first subset of SMI sensors may emit electromagnetic radiation outward from the fingertips of the user and serve as a machine substitute for the user's own fingertips. In this way, the first subset of SMI sensors can be used to characterize the surface quality of the remote target 144. The second subset of SMI sensors may emit a beam of electromagnetic radiation inward from the inner surface 152 of the wearable device (i.e., toward the user of the wearable device 130 (e.g., toward the user's fingertips)). In this way, the second subset of SMI sensors can be used to characterize the surface quality of a target inside the wearable device 130 (e.g., the user's skin). The surface quality of a user's fingertip can be used to determine, for example, whether the user is pressing their fingertip against an object; whether the skin of their fingertip is stretching as they feel or grip an object (e.g., pulling); whether it is hot or cold; whether it is dry or wet (e.g., due to sweating); etc. The surface quality of a user's fingertip can also be used to uniquely identify the user's fingertip, which may be necessary when obtaining a biometric for user authentication.

[0056] In some embodiments, the wearable device 130 may include one or more actuators 154, such as one or more tactile actuators and / or electrostatic actuators, for providing feedback to a user (or wearer) of the wearable device 130. In some cases, feedback may be provided to the user in response to or at an intensity corresponding to a surface quality sensed using a set of SMI sensors 132 and a processing system 150. The actuator 154 may provide feedback of the actuator in response to one or more actuation signals provided by the processing system 150 or a processor thereof.

[0057] Figure 2A An exemplary elevation view of a surface 200 having surface roughness and surface waviness is shown. The surface roughness and / or surface waviness may be characterized using SMI-based sensing and, in some cases, using a reference Figure 1A or Figure 1B The stylus or wearable device is characterized by a set of one or more SMI sensors and a processing system.

[0058] For the purposes of this specification, surface roughness and surface waviness are generally defined by the profile of a surface, but surface roughness has higher spatial frequency variations in surface profile than surface waviness. Surface roughness can be used to characterize, for example, human skin, while surface waviness can be used to characterize, for example, fingerprint ridges and fingerprint valleys. As another example, surface roughness can be used to characterize the height / depth, width, and / or spacing of surface texture (i.e., texture height, texture depth, texture width, and / or texture spacing), and surface waviness can be used to characterize lower spatial frequency variations in surface profile, such as can be defined by different texture subsets.

[0059] Figure 2A A surface 200 having surface roughness and surface waviness is shown. A first magnification 202 of the surface 200 shows larger features 204, 206 of the surface 200, which can be identified using SMI-based sensing and analyzed to characterize the surface waviness of the surface 200. A second (and larger) magnification 208 of the surface 200 shows smaller features 210, 212, 214 of the surface 200, which can also be identified using SMI-based sensing and analyzed to characterize the surface roughness of the surface 200.

[0060] Figure 2B An exemplary graph 220 of surface roughness and surface waviness, as determined by an indication of self-mixing within a resonant cavity of at least one SMI sensor, when the SMI sensor is emitting a beam of electromagnetic radiation toward the surface 200, as shown in reference Figure 2A The device comprising at least one SMI sensor is shown as a device across a surface 200. As shown, surface roughness 222 can be represented by the change in the envelope of the raw SMI signal. In contrast, surface waviness 224 can be represented by the change in target distance.

[0061] The surface roughness or surface waviness can be measured, for example, in terms of the root mean square (RMS) surface roughness R q , arithmetic mean deviation R a and / or RMS surface slope RΔ q To characterize, where:

[0062]

[0063] as well as

[0064]

[0065] Figure 2C An exemplary lateral data distribution 230 is shown from which the lateral data distribution can be determined. Figure 2A The lateral dependence (xy dependence) of the surface texture of the surface shown. The lateral dependence can also be determined from an indication of self-mixing.

[0066] The lateral correlation can be characterized, for example, in terms of the correlation length Sal and the texture aspect ratio Str. The correlation length is the minimum spacing R between the maximum heights of adjacent surface textures. min (i.e., Sal = R min The aspect ratio is R min max ratio, so that and R max The autocorrelation function can be used to determine:

[0067]

[0068] Figure 3 An exemplary SMI sensor 300 that can be used in one or more of the systems, devices, methods, or apparatus described herein is shown. The exemplary SMI sensor 300 includes a VCSEL 302 with an integrated resonant cavity (or intracavity) photodetector (RCPD) 304. The resonant cavity 306 can be defined by a pair of distributed Bragg reflectors, wherein one of the distributed Bragg reflectors allows a beam of electromagnetic radiation 308 to be emitted from the resonant cavity 306.

[0069] When the emitted electromagnetic radiation beam 308 is scattered or reflected from the target 310, a portion of the emitted electromagnetic radiation beam may return toward the VCSEL 302 and re-enter the resonant cavity 306. Within the resonant cavity 306, the returning portion of the beam self-mixes with the electromagnetic radiation generated by the VCSEL 302 and changes various properties of the VCSEL 302. The changed properties include changed optical properties, which may be detected by the RCPD 304 and converted into an electrical signal (SMI signal). The changed properties also include changed electrical properties, such as a changed current of a voltage driven VCSEL 302, or a changed junction voltage of a current driven VCSEL 302. Alternatives to the SMI sensor 300 may include a photodetector positioned above, below, or adjacent to the VCSEL, or circuitry for measuring the changed current or junction voltage of the VCSEL.

[0070] Figure 4AAn exemplary array of SMI sensors 400 is shown in relation to a surface 402 of an object 404. By way of example, the array of SMI sensors 400 is shown to include a first SMI sensor 400-1, a second SMI sensor 400-2, and a third SMI sensor 400-3. In alternative embodiments, the array of SMI sensors 400 may include more or fewer SMI sensors. Each of the SMI sensors 400-1, 400-2, 400-3 may be as described with reference to Figure 3 In some cases, the array of SMI sensors 400 may include a reference Figure 1A or Figure 1B Some or all of the SMI sensors in the stylus or wearable device.

[0071] Each of the SMI sensors 400-1, 400-2, 400-3 may have different characteristics. For example, different sensors of the SMI sensors 400-1, 400-2, 400-3 may have different angles of incidence (AOI, where AOI is the angle between the axis of the emitted electromagnetic radiation beam relative to a reference common to all SMI sensors (such as a planar target)), different numerical apertures (NA), different working distances (WD), different polarizations, different scanning plans, and / or different emitted electromagnetic radiation wavelengths. The different characteristics of the SMI sensors 400-1, 400-2, 400-3 provide optical diversity for different measurement channels provided by the SMI sensors 400-1, 400-2, 400-3, and may enable a processor or processing system that receives self-mixed indications from the array of SMI sensors 400 to discern a wider range of surface qualities and / or a wider range of surface quality characteristics. Some of the above differences or diversity (e.g., AOI, NA, or polarization, etc.) can be achieved through configuration of the SMI sensor itself and / or through shared or separate external optics (e.g., optional separate external optics 408-1, 408-2 and / or 408-3).

[0072] Different SMI sensors 400-1, 400-2, 400-3 may be mounted on a common substrate 406 as shown (e.g., on a common printed circuit board (PCB), on a common flexible circuit substrate, or on a common semiconductor die, where the SMI sensors 400-1, 400-2, 400-3 are individually addressable). Alternatively, different SMI sensors may be mounted on different substrates.

[0073] Figure 4B An exemplary SMI sensor 410 and a set of optics 412 are shown in relation to a surface 414 of a target 416. The SMI sensor 410 may be as described with reference to Figure 3In some cases, the SMI sensor 410 may provide a reference signal including Figure 1A or Figure 1B An SMI sensor (or the only SMI sensor) among multiple SMI sensors in the stylus or wearable device.

[0074] A set of optics 412 may be disposed above SMI sensor 410 in the optical path of an electromagnetic radiation beam 418 emitted by SMI sensor 410. In some cases, a set of optics 412 may also be disposed above other SMI sensors (i.e., in the optical path of electromagnetic radiation beams emitted by one or more other SMI sensors).

[0075] In some embodiments, the set of optical devices 412 may be a tunable set of optical devices. The processing system 420, its processor or other circuitry may be used to tune the set of optical devices 412. Tuning the set of optical devices 412 may provide diversity for the indication of self-mixing generated by the SMI sensor 410. Tuning the set of optical devices 412 may change, for example, the AOI, WD and / or polarization of the emitted electromagnetic radiation beam 418. The different tunable characteristics of the set of optical devices 412 may provide optical diversity for different measurement channels provided by the SMI sensor 410, and may enable a processor or processing system that receives the indication of self-mixing from the SMI sensor 410 to discern a wider range of surface qualities and / or a wider range of surface quality characteristics.

[0076] In some embodiments, the set of optics 412 may include a reciprocal beam splitter, such as a fiber coupler, a diffractive optical element, a partial reflector, etc. In these embodiments, the optical paths 422-1, 422-2 are reciprocal so that multiple combinations of round trip paths with different AOIs, WDs, and / or polarizations, etc., can be remixed back to the SMI sensor 410.

[0077] In some embodiments, the set of optical devices 412 may include an optical circulator (i.e., a device having three or more optical ports), such as a birefringent optical circulator. The SMI sensor 410 may emit an electromagnetic radiation beam 418 from a resonant cavity and into the set of optical devices 412, and receive a return portion of the electromagnetic radiation beam from the set of optical devices 412 and into the resonant cavity. Due to the optical circulator, the emitted electromagnetic radiation beam 418 and the return portion of the electromagnetic radiation beam may have non-reciprocal optical paths 422-1, 422-2 through the set of optical devices 412. The non-reciprocal paths may increase the diversity of the indication of self-mixing generated by the SMI sensor 410, and in some cases may be used for sub-surface quality sensing. In some embodiments, the set of optical devices 412 may be tunable to alternatively provide reciprocal or non-reciprocal emission and reception optical paths through the set of optical devices 412.

[0078] Figure 5 An exemplary method 500 for characterizing surface quality is shown. The method 500 may be performed, for example, by a set of one or more SMI sensors in combination with a processing system or processor. The set of one or more SMI sensors and the processing system or processor may include any of the SMI sensors and processing systems (or processors) described herein.

[0079] At block 502 , method 500 may include receiving an indication of self-mixing from a set of one or more SMI sensors.

[0080] At block 504 , method 500 may include determining at least one of a range or a directional velocity relative to a target using the self-mixed indication.

[0081] At block 506, method 500 may include characterizing the light field speckle of the target using the indication of self-mixing and at least one of range or directional velocity. The light field speckle may be characterized, for example, in terms of light field speckle contrast, phase shift, and / or light field speckle correlation length.

[0082] At block 508 , method 500 may include characterizing a surface quality of an object using the characterization of light field speckle.

[0083] At box 510, method 500 may include using the characterization of the surface quality to perform one or more machine-based operations. In some embodiments, the operation may include drawing strokes on a display based on the surface quality. For example, the surface quality may be used to draw a stroke that is performed by a stylus that includes a set of one or more SMI sensors. The stroke may be drawn, for example, on an electronic display of a computer, mobile device, or wearable device. In some cases, the stroke may be an alphanumeric character, an electronically painted, or an electronically painted stroke. The stroke may be drawn based on the surface quality having appropriately sharp edges or diffuse edges, as determined by the characteristics of the surface quality and the type of brush, pen, or pencil simulated by the stylus. Alternatively or in addition, the operation may include indicating to the user the type of surface they are writing or drawing on (e.g., a glossy surface, a matte surface, etc.).

[0084] In some embodiments, the operations at block 510 may include animating the interaction between the virtual object and the target in the AR or VR environment. The animation may be performed in response to the surface quality of the target. For example, in an AR or VR environment depicting a virtual balloon on a display, if 1) the balloon is actually in contact with the target, and 2) the surface quality of the target is rough enough that it would normally cause the balloon to burst, the AR or VR environment may animate the "bursting" of the balloon.

[0085] In some embodiments, the operation at block 510 may include causing the actuator to provide feedback to the user indicating the quality of the surface. Figure 1A or Figure 1B The tactile actuator and / or electrostatic actuator of the stylus or wearable device provides tactile and / or electrostatic feedback to the user of the stylus or wearable device.

[0086] In some embodiments, the operation at block 510 may include causing an actuator to provide feedback to a user that masks the surface quality. For example, destructive feedback may be provided to mask vibrations of the sensed surface quality.

[0087] Figure 6 An exemplary method 600 of operating an SMI sensor is shown, which in some cases may be one of the multiple SMI sensors described herein. According to the method 600, a system may generate an initial digital signal and process the digital signal to generate a triangular modulated laser bias current 602. In the example shown, the initial step signal may be generated by a digital generator to approximate a triangular function (e.g., a triangular modulated laser bias current 602). The triangular modulated laser bias current 602 may be input to a digital-to-analog (DAC) converter 604. The resulting voltage signal may then be filtered by a low pass filter 606 to remove quantization noise. Alternatively, an analog signal generator may be used to directly generate an equivalent triangular voltage signal. The filtered voltage signal may be input to a voltage-to-current converter 608 before using the triangular modulated laser bias current to bias the VCSEL diode 610.

[0088] As described above, scattering or reflection from a target may trigger self-mixing of electromagnetic radiation within the VCSEL diode 610. The self-mixing causes the operating parameters of the VCSEL diode 610 to change. The changed parameters may be measured or inferred from the operating parameters of the VCSEL diode 610 or from the operating parameters of an associated photodetector. These changes may be measured to produce a signal 612 (e.g., a combination of the triangular modulated laser bias current 602 and the self-mixing signal). The signal 612 may have been measured by a photodetector and may be a triangular wave combined with smaller and higher frequency signals that are related to the changed operating parameters of the VCSEL diode 610.

[0089] Signal 612 may pass through a high pass filter 614, which may convert the main rising and falling ramp components of signal 612 into a DC offset. Since signal 612 may be a current signal generated by a photodetector, a transimpedance amplifier 616 may generate a corresponding voltage output for further processing.

[0090] The voltage output of the transimpedance amplifier 616 may be sampled and quantized by an analog-to-digital converter (ADC) 618. Equalization may be applied to clean up the remaining remnants of the triangular signal received by the photodiode immediately before a digital fast Fourier transform (FFT) is applied to the output of the ADC 618, thereby isolating the interference signal. The initial digital signal value from the digital generator for generating the triangular modulated laser bias current 602 may be used as an input to a digital high pass filter 620 to generate a digital signal corresponding to the output of the ADC 618. A digital variable gain circuit 622 may apply an adjustable gain to the output of the digital high pass filter 620.

[0091] The output of the digital variable gain circuit 622 may be used as one input to a digital equalizer and subtractor 624. The other input to the digital equalizer and subtractor 624 may be the output of the ADC 618. The two signals may be subtracted and used as feedback to adjust the gain provided by the digital variable gain circuit 622.

[0092] Once the feedback has acquired sufficient correlation, the FFT and pitch extraction circuit 626 may apply an FFT to the output of the digital equalizer and subtractor 624 (i.e., to the indication of self-mixing). From the obtained FFT spectrum, the displacement or movement of the target (e.g., absolute distance and directional velocity) may be inferred, as indicated by block 628. During the FFT and pitch extraction circuit 626 step, the processing electronics executing part of the method 600 may perform spectral analysis (e.g., frequency domain analysis) on the signal received from the digital equalizer and subtractor 624. The spectral analysis may isolate the signal corresponding to the change in the operating parameter of the VCSEL diode 610, and may be used to measure real-world events (e.g., the distance between the target and the VCSEL diode 610, the velocity of the target or the VCSEL diode 610, etc.). A time domain analysis of the indication of self-mixing may also be performed at block 626.

[0093] The output of the FFT and pitch extraction circuit 626, and in some cases the absolute distance and directional velocity referenced in box 628, can be used to characterize light field speckle (e.g., perform speckle analysis) at box 630 as described herein, and further characterize surface quality (e.g., perform surface analysis) at box 630.

[0094] Fig. 7A An exemplary light field speckle envelope 700 is shown. The light field speckle envelope 700 may be defined by the amplitude of the SMI signal when a beam of electromagnetic radiation emitted by the SMI sensor is scanned over the surface of a target. The SMI sensor may be any SMI sensor described herein.

[0095] Figure 7B It shows that based on Figure 6The data obtained at blocks 626, 628, and 630 of (and more specifically, based on Fig. 7A 7 and 8. An exemplary graph of light field speckle contrast 710 and light field speckle correlation length 712 (spectral analysis of temporal data shown in FIG. 1 ) is provided. Light field speckle contrast is the calculated distribution of the amplitude of the light field speckle envelope 700 and can be used to determine the standard deviation and other characteristics of the light field speckle. In some cases, the speckle correlation length can be calculated from the autocorrelation of the temporal data and converted to spatial (length) units using the measured target velocity.

[0096] Fig. 7A and Figure 7B The data shown may be derived from a single SMI sensor for providing a single measurement channel or for a self-mixed indication of each of a plurality of measurement channels (provided by a single or a plurality of SMI sensors). When determining data for a plurality of measurement channels, each measurement channel may differ from the other measurement channels in, for example, AOI, NA, WD, polarization, and / or wavelength of emitted electromagnetic radiation.

[0097] Figure 8A-8C An exemplary correlation between properties of light field speckle (i.e., optical properties of a surface) and properties of surface quality (i.e., physical properties of a surface) is shown. Fig. 8A An exemplary relationship 800 between light field speckle contrast and surface roughness is shown for SMI sensors with different parameters (e.g., different AOI / NA / wavelength / ...). As shown, light field speckle contrast may not have a monotonic relationship with surface roughness, but it does have a defined relationship.

[0098] Figure 8B An exemplary relationship 810 between light field speckle correlation length and surface correlation length for SMI sensors with different parameters (e.g., different AOI / NA / wavelength / ...) is shown. As shown, the light field speckle correlation may not have a monotonic relationship with the surface correlation length, but it does have a defined relationship.

[0099] Figure 8C An exemplary use of light field speckle properties is shown for modeling the angular reflectivity of a surface 820. As shown, the angular reflectivity of a surface may be characterized as specular, diffuse, or volumetric, depending on the distribution of the light field speckle data.

[0100] Fig. 9An exemplary transfer function 900 for deriving surface quality characteristics from light field speckle characteristics and an indication of diversity of SMI sensor parameters is shown. On the left side of the transfer function 900, light field characteristics such as light field speckle contrast 902 and light field speckle correlation length 904 are provided as inputs to the transfer function. Indications of diversity in SMI sensor parameters such as SMI AOI / NA diversity 906, SMI wavelength diversity 908, and SMI polarization diversity 910 are also provided as inputs to the transfer function 900. Additional or alternative light field speckle characteristics and / or indications of diversity may also be provided as inputs to the transfer function 900.

[0101] On the right side of the transfer function 900, surface quality characteristics are shown as outputs of the transfer function. The surface quality characteristics may include, for example, RMS surface roughness 912 below half a wavelength, RMS surface roughness 914 above half a wavelength, surface correlation length 916, RMS surface slope 918, subsurface scattering 920, and surface retroreflectivity 922. Additional or alternative surface quality characteristics may also be provided as outputs of the transfer function 900. A deterministic or statistical transfer function may be established between the left and right sides of the transfer function 900 through regression, machine learning, etc. For a statistical transfer function, the output on the right side may be associated with both a value and a probability.

[0102] As shown, some inputs to transfer function 900 may affect some outputs of transfer function 900 more than other inputs, as indicated by the arrows mapping the inputs of transfer function 900 to the outputs of transfer function 900. However, any of the inputs may affect any of the outputs to some extent (although not always to a statistically significant extent).

[0103] Fig.10 A set of exemplary stroke types 1000 are shown that may be drawn based on a surface quality sensed using a set of one or more SMI sensors. For example, depending on the surface quality sensed using a set of one or more SMI sensors, the processing system may draw the stroke as a first stroke 1002 when the surface quality is a first surface quality, or draw the stroke as a second stroke 1004 when the surface quality is a second surface quality, or draw the stroke as a third stroke 1006 when the surface quality is a third surface quality, or draw the stroke as a fourth stroke 1008 when the surface quality is a fourth surface quality, or draw the stroke as a fifth stroke 1010 when the surface quality is a fifth surface quality.

[0104] Fig.11A and Fig. 11B An alternative animation of a virtual object is shown, which is responsive to the surface quality of the object. For example, Fig.11AA virtual balloon 1100 is shown in an AR environment, deflected from a physical object 1102 that the processing system has determined to have a relatively smooth surface quality. Fig. 11B The virtual balloon 1100 is shown bursting when it contacts a physical object 1104 that the processing system has determined to have a sufficiently rough surface quality.

[0105] Fig.12 An exemplary electrical block diagram of an electronic device 1200 is shown, which in some cases may be a reference Figure 1A or Figure 1B The stylus or wearable device may be the same as the reference Figure 1A or Figure 1B The stylus or wearable device communicates with a remote device (e.g., a mobile device or a computer). The electronic device 1200 may optionally include an electronic display 1202 (e.g., a light-emitting display), a processor 1204, a power supply 1206, a memory 1208 or storage device, a sensor system 1210, and / or an input / output (I / O) mechanism 1212 (e.g., an input / output device, an input / output port, or a tactile input / output interface). The processor 1204 may control some or all operations of the electronic device 1200. The processor 1204 may communicate directly or indirectly with some or all other components of the electronic device 1200. For example, a system bus or other communication mechanism 1214 may provide communication between the electronic display 1202, the processor 1204, the power supply 1206, the memory 1208, the sensor system 1210, and the I / O mechanism 1212.

[0106] Processor 1204 may be implemented as any electronic device capable of processing, receiving or sending data or instructions, whether such data or instructions are in the form of software or firmware or encoded in other ways. For example, processor 1204 may include a microprocessor, a central processing unit (CPU), an application specific integrated circuit (ASIC), a digital signal processor (DSP), a controller, or a combination of such devices. As described herein, the term "processor" is intended to cover a single processor or processing unit, multiple processors, multiple processing units, or one or more other appropriately configured computing elements. In some cases, processor 1204 may provide a portion or all of the processing systems or processors described herein.

[0107] It should be noted that components of electronic device 1200 may be controlled by multiple processors. For example, selected components of electronic device 1200 (e.g., sensor system 1210) may be controlled by a first processor and other components of electronic device 1200 (e.g., electronic display 1202) may be controlled by a second processor, where the first processor and the second processor may or may not be in communication with each other.

[0108] The power supply 1206 may be implemented with any device capable of providing energy to the electronic device 1200. For example, the power supply 1206 may include one or more batteries or rechargeable batteries. Additionally or alternatively, the power supply 1206 may include a power connector or a power cord that connects the electronic device 1200 to another power source such as a wall outlet.

[0109] The memory 1208 may store electronic data that may be used by the electronic device 1200. For example, the memory 1208 may store electronic data or content, such as, for example, audio and video files, documents and applications, device settings and user preferences, timing signals, control signals, instructions, and / or data structures or databases. The memory 1208 may include any type of memory. By way of example only, the memory 1208 may include random access memory, read-only memory, flash memory, removable memory, other types of storage elements, or combinations of these memory types.

[0110] The electronic device 1200 may also include one or more sensor systems 1210 positioned at almost any location on the electronic device 1200. In some cases, the sensor system 1210 may include one or more SMI sensors positioned and / or configured as described herein. The sensor system 1210 may be configured to sense one or more types of parameters, such as, but not limited to, vibration; light; touch; force; heat; movement; relative motion; biometric data of a user (e.g., biometric parameters); air quality; proximity; position; connectivity; surface quality; and the like. By way of example, the sensor system 1210 may include an SMI sensor, a thermal sensor, a position sensor, an optical or optical sensor, an accelerometer, a pressure transducer, a gyroscope, a magnetometer, a health monitoring sensor, and an air quality sensor, among others. In addition, the one or more sensor systems 1210 may utilize any appropriate sensing technology, including, but not limited to, interferometry, magnetism, capacitance, ultrasound, resistance, optics, sound, piezoelectric, or thermal technology.

[0111] The I / O mechanism 1212 may transmit or receive data from a user or another electronic device. The I / O mechanism 1212 may include an electronic display 1202, a touch-sensitive input surface, a crown, one or more buttons (e.g., a graphical user interface "home" button), one or more cameras (including an under-display camera), one or more microphones or speakers, one or more ports such as a microphone port, and / or a keyboard. Additionally or alternatively, the I / O mechanism 1212 may send electronic signals via a communication interface such as a wireless, wired, and / or optical communication interface. Examples of wireless and wired communication interfaces include, but are not limited to, cellular and Wi-Fi communication interfaces.

[0112] The above description uses specific nomenclature to provide a thorough understanding of the embodiments for explanation. However, it will be apparent to those skilled in the art that, after reading this specification, the embodiments can be practiced without specific details. Therefore, for the purpose of illustration and description, the foregoing description of the specific embodiments described herein is presented. They are not intended to be exhaustive or to limit the embodiments to the precise form disclosed. It will be apparent to those of ordinary skill in the art that, after reading this specification, many modifications and variations are possible in view of the above teachings.

[0113] As described above, one aspect of the present technology may be the collection and use of data available from various sources, including biometric data (e.g., the surface quality of a user's skin or fingerprints). The present disclosure contemplates that, in some cases, the collected data may include personal information data that uniquely identifies or can be used to identify, locate, or contact a specific person. Such personal information data may include, for example, biometric data (e.g., fingerprint data) and data linked thereto (e.g., demographic data, location-based data, phone number, email address, home address, data or records related to the user's health or fitness level (e.g., vital sign measurements, medication information, exercise information), date of birth, or any other identifying or personal information).

[0114] The present disclosure recognizes that the use of such personal information data in the present technology can be used to benefit users. For example, the personal information data can be used to authenticate users to access their devices, or to collect performance metrics for the user's interaction with an augmented or virtual world. In addition, the present disclosure also contemplates other uses of personal information data that benefit users. For example, health and fitness data can be used to provide insights into the user's overall health, or can be used as positive feedback to individuals using technology to pursue health goals.

[0115] This disclosure envisions that entities responsible for collecting, analyzing, disclosing, transmitting, storing or otherwise using such personal information data will comply with established privacy policies and / or privacy practices. Specifically, such entities should implement and adhere to privacy policies and practices that are recognized as meeting or exceeding industry or government requirements for maintaining the privacy and security of personal information data. Such policies should be easily accessible to users and should be updated as the collection and / or use of data changes. Personal information from users should be collected for legitimate and reasonable purposes of the entity and not shared or sold outside of these legitimate uses. In addition, such collection / sharing should be performed after receiving informed consent from the user. In addition, such entities should consider taking any necessary steps to defend and secure access to such personal information data and ensure that others who have access to personal information data comply with their privacy policies and processes. In addition, such entities may subject themselves to third-party assessments to demonstrate their compliance with widely accepted privacy policies and practices. In addition, policies and practices should be adjusted to specific types of personal information data collected and / or accessed, and to applicable laws and standards including specific considerations of jurisdiction. For example, in the United States, the collection or access of certain health data may be governed by federal and / or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA), while health data in other countries may be subject to other regulations and policies and should be handled accordingly. Therefore, different privacy practices should be maintained in each country for different types of personal data.

[0116] Regardless of the foregoing, the present disclosure also contemplates implementation schemes in which users selectively block the use or access of personal information data. That is, the present disclosure contemplates that hardware elements and / or software elements may be provided to prevent or block access to such personal information data. For example, with respect to an advertising delivery service, the technology of the present invention may be configured to allow a user to choose to "opt in" or "opt out" at any time during or after registration for the service to participate in the collection of personal information data. As another example, a user may choose not to provide data to a target content delivery service. In yet another example, a user may choose to limit the length of time that data is maintained, or to completely prohibit the development of a baseline profile for the user. In addition to providing "opt-in" and "opt-out" options, the present disclosure contemplates providing notifications related to access or use of personal information. For example, a user may be notified that their personal information data will be accessed when downloading an application, and then the user may be reminded again just before the personal information data is accessed by the application.

[0117] Furthermore, it is an object of the present disclosure that personal information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use. Risks can be minimized by limiting data collection and deleting data once it is no longer needed. Additionally, and when applicable, including in certain health-related applications, data de-identification can be used to protect the privacy of users. Where appropriate, de-identification can be facilitated by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of the data stored (e.g., collecting location data at the city level rather than at the address level), controlling how the data is stored (e.g., aggregating data across users), and / or other methods.

[0118] Thus, while the present disclosure broadly covers the use of personal information data to implement one or more of the various disclosed embodiments, the present disclosure also contemplates that various embodiments may also be implemented without access to such personal information data. That is, various embodiments of the present technology will not fail to function properly due to the lack of all or a portion of such personal information data. For example, content may be selected and delivered to a user by inferring preferences based on non-personal information data or an absolute minimum amount of personal information, such as content requested by a device associated with the user, other non-personal information available to a content delivery service, or publicly available information.

Claims

1. An electronic device, comprising: a housing defining a stylus body having a tip; a set of one or more self-mixing interferometry (SMI) sensors attached to the housing and comprising: a set of one or more electromagnetic radiation emitters having a set of one or more resonant cavities and configured to emit a set of one or more electromagnetic radiation beams having a set of one or more known relationships to the tip; and a set of one or more detectors configured to generate an indication of self-mixing within the set of one or more resonant cavities; and A processor, the processor being configured to: characterizing a light field speckle of a target using an indication of said self-mixing; characterizing a surface quality of the object using the characterization of the light field speckle and the set of one or more known relationships; and One or more machine-based operations are performed using the characterization of the surface quality.

2. The electronic device according to claim 1, wherein: The processor is further configured to: While at least one of characterizing the light field speckle or characterizing the surface quality, and using the indication of self-mixing to determine at least one of: a pose of the housing relative to the target; the distance from the housing to the target; or The speed of movement between the housing and the target.

3. The electronic device of claim 1 , wherein the processor is configured to characterize the light field speckle by: performing a time domain analysis of the indication of the self-mixing; performing a frequency domain analysis of the indication of the self-mixing; and Determine at least one of the following from at least one of the time domain analysis or the frequency domain analysis: Light field speckle contrast; phase shift; or Light field speckle correlation length.

4. The electronic device according to claim 1, wherein: The set of one or more SMI sensors includes at least a first SMI sensor and a second SMI sensor, wherein the at least first SMI sensor and the second SMI sensor have different: Angle of incidence; Numerical aperture; Working distance; Polarization; or The wavelength of electromagnetic radiation emitted.

5. The electronic device according to claim 1, further comprising: a set of optical devices, the set of optical devices being arranged above an SMI sensor in the set of one or more SMI sensors; wherein, The processor is configured to tune the set of optical devices, the tuning providing diversity in the indication of the self-mixing.

6. The electronic device of claim 1 , wherein characterizing the surface quality comprises determining at least one of: Surface roughness; Surface waviness; Subsurface scattering within the target; or The refractive index of the target.

7. The electronic device according to claim 1, further comprising: A motion sensor; wherein: The processor is further configured to characterize the surface quality in response to the output of the motion sensor.

8. The electronic device of claim 1, wherein the surface quality comprises surface roughness.

9. The electronic device of claim 1, wherein the surface quality comprises texture height and at least one of texture width or texture pitch.

10. The electronic device according to claim 1, further comprising: A set of optical devices; wherein, an SMI sensor of the set of one or more SMI sensors, emitting a beam of electromagnetic radiation from the resonant cavity and into the set of optical devices; and receiving a return portion of the electromagnetic radiation beam from the set of optical devices and passing it into the resonant cavity; and The emitted electromagnetic radiation beam and the returned portion of the electromagnetic radiation beam have non-reciprocal optical paths through the set of optical devices.

11. A method comprising: receiving an indication of self-mixing from a set of one or more self-mixing interferometry (SMI) sensors disposed in the stylus as the stylus is moved relative to a target having a surface quality to define a stroke; using the self-mixed indication to determine at least one of a range or a directional velocity relative to the target; characterizing a light field speckle of the target using the indication of the self-mixing and the at least one of the range or the directional velocity; characterizing the surface quality of the object using the characterization of the light field speckle; as well as The stroke is drawn on an electronic display based on the surface quality.

12. The method according to claim 11, further comprising: The actuator is caused to provide feedback to a user indicative of the quality of the surface.

13. The method according to claim 11, further comprising: The actuator is caused to provide feedback to the user masking the surface quality.

14. A method for characterizing surface quality, the method comprising: receiving an indication of self-mixing from a set of one or more self-mixing interferometry (SMI) sensors disposed in the stylus as the stylus moves relative to a target having a surface quality; characterizing a light field speckle of the target using the indication of the self-mixing; characterizing the surface quality of the target using the characterization of the light field speckle; as well as The tactile actuator provides, feedback indicative of the quality of the surface; or Masking feedback of the surface quality.

15. The method of claim 14, wherein characterizing the surface quality comprises determining at least one of: Surface roughness; Surface waviness; Subsurface scattering within the target; or The refractive index of the target.

16. An electronic device, comprising: a housing defining a wearable device; a set of one or more self-mixing interferometry (SMI) sensors attached to the housing and comprising: A set of one or more electromagnetic radiation transmitters, the set of one or more electromagnetic radiation transmitters having a set of one or more resonant cavities and configured to emit a set of one or more electromagnetic radiation beams, at least one of the set of one or more electromagnetic radiation beams pointing outward from an exterior of the wearable device; or pointing inward from an interior of the wearable device; a set of one or more detectors configured to generate an indication of self-mixing within the set of one or more resonant cavities; and A processor, the processor being configured to: characterizing a light field speckle of a target using an indication of said self-mixing; characterizing the surface quality of the object using the characterization of the light field speckle; and One or more machine-based operations are performed using the characterization of the surface quality.

17. The electronic device of claim 16, wherein the wearable device is a glove.

18. A method comprising: receiving an indication of self-mixing from a set of one or more self-mixing interferometry (SMI) sensors disposed in the stylus as the stylus is moved relative to a target having a surface quality to define a stroke; using the self-mixed indication to determine at least one of a range or a directional velocity relative to the target; characterizing a light field speckle of the target using the indication of the self-mixing and the at least one of the range or the directional velocity; characterizing the surface quality of the object using the characterization of the light field speckle; as well as Interactions between a virtual object and the target are animated in an augmented reality or virtual reality environment, wherein the animation is performed in response to the surface quality of the target.

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