Abstract: Systems, devices, media, and methods are presented for gaze-based control of device operations. One method includes receiving a video stream from an imaging device, the video stream depicting one or more eyes, determining a gaze direction for the one or more eyes depicted in the video stream, detecting a change in the gaze direction of the one or more eyes, and triggering an operation in a client device based on the change in the gaze direction.

Abstract: A method for a device to acquire biometric information includes acquiring a plurality of images including an ocular region using an infrared ray (IR) image sensor, detecting a sclera region in each of the plurality of acquired images, sensing a change of the detected sclera region, and determining biometric information based on information on the sensed change of the sclera region.

Abstract: An image of an eye of a user from an image sensor can be received, the image resulting from the image sensor detecting light from one or more illuminators reflected from the eye of the user. A glint is identified in the image as a representation in the image of a reflection of light from a cornea of the eye of the user or from a sclera of the eye of the user. A first pixel intensity of the glint is determined, a second pixel intensity of neighbor pixels of the glint is determined, and an absolute value of the difference between the first pixel intensity and the second pixel intensity is determined. The glint is identified as a representation of a reflection from the sclera of the eye of the user on condition that the determined absolute value of the difference is below a predetermine threshold value.

Abstract: An image processing method applied by a medical imaging device is proposed, including at least one camera and at least one display screen on which is displayed a medical image showing a region of interest of a patient, the method being characterized in that the region of interest is determined by the following steps, the screen and the camera being laid out so as to be facing a practitioner simultaneously, acquisition by the camera of at least one tracking image containing the eyes of the practitioner, analysis of the tracking image so as to localize in the medical image at least one pixel of interest contemplated by the practitioner on the screen from the orientation of the eyes of the practitioner, processing the medical image so as to select the region of interest from the localized pixel of interest.

Abstract: An object identifying and tracking device is provided. The device includes a first image capturer to capture a first raw image of an object, a second image capturer to capture a second raw image of the object, a first processor, a second processor and a post processor. The object includes a first light source emitting light of a first wavelength and a second light source emitting light of a second wavelength. The first processor and the second processor respectively receive the first and the second raw images and respectively extract a first group of information associated with the light of the first wavelength and a second group of information associated with the light of the second wavelength emitted from the object. The post processor processes the first group of information and the second group of information to obtain a third group of information.

Abstract: A progressive addition lens, a manufacturing method and a design method therefor, and a progressive addition lens manufacturing system, capable of flexibly adapting to an actual use state of a wearer and are optimal for each wearer, for determining a main line of sight considering not only convergence of the eye occurring with near vision including passive accommodative power but also convergence of the eye induced by using an accommodative power margin of the eye. The design method includes a first main line of sight calculation step of calculating a first main line of sight, where accommodative convergence caused by use of the accommodative power margin is considered, based on lens design information including at least information of accommodative power of the eye and a final main line of sight determination step of determining a final main line of sight of a lens from the first main line of sight.

Abstract: This invention relates to methods and apparatus for improving communications between humans and devices. The invention provides a method of modulating operation of a device, comprising: providing an attentive user interface for obtaining information about an attentive state of a user; and modulating operation of a device on the basis of the obtained information, wherein the operation that is modulated is initiated by the device. Preferably, the information about the user's attentive state is eye contact of the user with the device that is sensed by the attentive user interface.

Abstract: Systems, devices, and methods for laser eye tracking are described. Laser eye tracking involves scanning laser light over the eye and detecting diffuse reflections of the laser light with one or more photodetector(s). While conventional camera-based eye tracking techniques rely on detecting and identifying specific reflections (i.e., Purkinje images such as the “glint”), the laser eye tracking techniques described herein detect and identify a reduction in reflection intensity due to transmission of laser light through the pupil and/or increased diffusivity of reflections from the cornea relative to reflections from the sclera. This effect is referred to herein as the “corneal shadow” effect. Laser eye tracking uses considerably less power than conventional camera-based eye tracking techniques.

Abstract: A sensing device with an odd-symmetry grating projects near-field spatial modulations onto an array of closely spaced pixels. Due to physical properties of the grating, the spatial modulations are in focus for a range of wavelengths and spacings. The spatial modulations are captured by the array, and photographs and other image information can be extracted from the resultant data. Pixels responsive to infrared light can be used to make thermal imaging devices and other types of thermal sensors. Some sensors are well adapted for tracking eye movements, and others for imaging barcodes and like binary images. In the latter case, the known binary property of the expected images can be used to simplify the process of extracting image data.

Abstract: A system and method are provided that use eye gaze as a pointing or selection tool, which enables hands-free operation of a display such as a television. wherein the use of eye gaze as an input can also lead to easier and faster interactions when compared to traditional remote controls. A system and method are also provided that use eye tracking on displays such as televisions to determine what content was viewed and, by association, what content was of most interest to the user. Systems and methods are also described that enable interaction with elements displayed in an augmented reality environment using gaze tracking and for controlling gaze tracking on a portable electronic device.

Abstract: Apparatus for testing a patient's visual field, the apparatus comprising: means for recording the results of the patient's responses to one or more visual field targets (5) presented during a visual field test; and a fixation loss switch activatable by an observer observing the patient during the visual field test for identifying periods of fixation loss by the patient. The results recorded during periods of fixation loss are identified as being unreliable. Also disclosed is a method of testing a patient's visual field.

Abstract: Aspects are generally directed to a high speed pupil detection system and method. In one example, the method includes receiving optical radiation reflected from an eye at one or more pixels of an optical sensor, reading-out a value of each of the pixels in a plurality of lines to progressively generate an image frame of a video image stream, the value of each of the pixels being based on a flux of the received optical radiation, identifying a first chord within a first line of the plurality of lines, identifying a second chord within a second line of the plurality of lines, the first chord and second chord being separated by a subset of the plurality of lines, and determining a location of a center of a pupil of the eye based on a two chord crossing of the pupil with the first chord and the second chord.

Abstract: Provided is a detection apparatus and detection method. The detection apparatus includes an imaging unit that images a subject and an eye gaze detector detects the subject's eye gaze direction based on a captured image. A diagnostic image is displayed that includes an image including a face image and a geometric pattern image. A first gaze point is detected as a gaze point of the subject in the person image based on the eye gaze direction and a second gaze point is detected as a gaze point of the subject in a determination region in the geometric pattern image.

Abstract: A computer system may track the user's eye gaze on a display device over time using an eye tracker. When the computer system detects a risk associated with a graphical object and determines that the user's gaze is close to the graphical object, it may display a warning message indicating the risk. The computer system may display the warning message at a location that corresponds to the graphical object associated with the risk. Furthermore, when the computer system detects a risk and determines that the user's gaze is not at the graphical object that needs the user's immediate attention, it may display a warning message near the user's current gaze to notify the user. If desired, the warning message may be hidden based on the user's gaze, such as when the user moves his gaze away from the detected risk.

Abstract: In a measurement by means of OCT, when dispersion is present in a measured target or an optical system in the vicinity of the measured target, resolution of the measurement is degraded. One spectral interference fringe intensity is acquired when a phase difference between measurement light and reference light is not introduced, two spectral interference fringe intensities are acquired in a time-series manner when a phase difference of ? is introduced, a required calculation is performed based on the intensity, and a tomographic image not having reduced resolution due to dispersion is acquired.

Abstract: A gaze position detection apparatus includes: a memory which stores a plurality of registered move patterns of a gaze position and correction information of the gaze position included in the registered move pattern for each of the registered move patterns; a move pattern detection unit which detects a move pattern of a user's gaze position, from a plurality of measurement points of the user's gaze position which are obtained from data items representing a user's gaze direction generated by a gaze detection device in different timing; a similar-pattern extraction unit which extracts the registered move pattern similar to the move pattern of the user's gaze position from among the plurality of registered move patterns; and a correction unit which corrects the gaze position included in the move pattern of the user's gaze position using the correction information of the gaze position for the similar registered move pattern.

Abstract: A display, imaging units that capture a subject, an eye gaze detector that detects an eye gaze direction of the subject, from the captured image captured by the imaging units, a gaze point detector that detects a gaze point of the subject in a display region of the display, based on the eye gaze direction, an output controller that displays any of a plurality of diagnosis images on the display, selects the diagnosis image to be displayed next according to a position of the gaze point detected when the diagnosis image is displayed, from the plurality of diagnosis images, and further displays the selected diagnosis image on the display, and an evaluator that calculates an evaluation value of the subject, based on the gaze point detected by the gaze point detector when the diagnosis image is displayed.

Abstract: Systems and methods for measuring dysphotopsia are provided. These systems and methods can be used to objectively quantify positive and negative dysphotopsia. One embodiment provides a system and method for determining dysphotopsia that uses a first light source configured to provide light energy to illuminate a model eye, a refractor for refracting the light energy from the first light source and directing it into the model eye, a first electronic light sensor for measuring an amount of light in the model eye; a second light source configured to provide light energy to illuminate the model eye, wherein the light energy from the second light source is introduced at an angle from the first light source; and a second electronic light sensor for measuring the amount of light in the model eye, wherein the second electronic light sensor is capable of taking measurements from various points around the model eye. Data from these measurements can then analyzed to provide an objective measurement of dysphotopsia.

Abstract: A head mounted display (HMD) includes one or more light field cameras for tracking one or both eyes of a user wearing the HMD. The HMD optionally includes light sources positioned inside the HMD and that illuminate one or both of the eyes of the user. The light field camera captures a plenoptic image of the user's eye. The plenoptic image includes light intensity data and direction data of the captured light rays. An eye tracking system updates a 3D light field model of the user's eye based on depth information from the plenoptic image frame. The eye tracking system identifies an iris plane of the user's eye using the 3D light field model. The eye tracking system determines a gaze direction of the user's eye by identifying the normal to the center of the iris plane.

Abstract: An embodiment of the invention includes a system that tracks a user's pupillary response to content located on a web page. The system then determines a cognitive load for the user that is based on the measured response. Cognitive load refers to the total amount of mental activity imposed on working memory in any one instant. Further, the system may aggregate the cognitive load data for one user over time, for many different users, and/or for many different users over time. The cognitive load may be determined for different portions of a displayed page, such as a document object model (DOM) included on the page. The cognitive load may be specified for different elements that make up the DOM. Also, cognitive load may be apportioned over several different DOM elements at one moment in time or over a period of time. Other embodiments are described herein.

Abstract: A system and method are provided for detecting and monitoring Pupillary Light Reflex responses and physical conditions using a portable video capture device (PVCD) for the purpose of diagnosing or monitoring impairment due to consumption of intoxicating substance or neurological disorder due to trauma or illness. In one embodiment, the PVCD is placed in an opaque enclosure, and positioned over one or both eyes. Video of the eyes is captured over a predetermined time using a video camera of the PVCD, and the video processed to measure changes in a feature of at least one eye. Data from the measured changes is analyzed together with additional physical data collected on a condition of the user, to estimate a degree of impairment. The degree of impairment and additional physical data is output to the user through a user interface in the PVCD and stored in local and remote memory for monitoring.

Abstract: A method is provided for determining a point of gaze directed at a graphical display. The method comprises: a) acquiring an image of at least one eye of a user containing at least one gaze aspect and at least one reference aspect; b) extracting image aspects from the image, the image aspects comprising a set of reference aspects and a set of gaze aspects corresponding to the image; c) extracting a set of features for each of said image aspects; d) computing a set of feature vectors between said set of gaze aspects and said set of reference aspects; e) computing a point of gaze for each of said set of feature vectors, using a predefined mathematical relationship; and f) using a predefined rule to combine the computed points of gaze into a final point of gaze on the graphical display.

Abstract: Autofocusing eyewear for correcting eye accommodative dysfunctions includes a pupil tracking VOG (video-oculography) system to determine location of the pupils, a focus-tunable lens and a controller to focus the lens based on the position of the pupils.

Abstract: Systems, devices, and methods are disclosed which may be used to detect and determine the extent of brain trauma, mental impairment, physical disability, or other brain dysfunction by tracking one or more ocular responses.

Abstract: A system mounted within eyewear or headwear to unobtrusively produce and track reference locations on the surface of one or both eyes of an observer is provided to improve the accuracy of gaze tracking. The system utilizes multiple illumination sources and/or multiple cameras to generate and observe glints from multiple directions. The use of multiple illumination sources and cameras can compensate for the complex, three-dimensional geometry of the head and the significant anatomical variations of the head and eye region that occurs among individuals. The system continuously tracks the initial placement and any slippage of eyewear or headwear. In addition, the use of multiple illumination sources and cameras can maintain high-precision, dynamic eye tracking as an eye moves through its full physiological range.

Abstract: A computer determines a cognitive overload of a user interacting with a visual display based on eye tracking data. The visual display includes content of the dashboard and graphical elements of the content of the dashboard. The computer adjusts the visual display by modifying the content based on determining the cognitive overload.

Abstract: A method for displaying images on a head-mounted display (HMD) device that compensates for a user's vestibulo-ocular reflex (VOR) response. The displayed HMD image is compensated for predicted eye position such that the displayed image stays centered on the fovea of the eye, during transient eye movement caused by head motion, resulting in better display readability, discernment and cognitive processing.

Abstract: A system and method tracks a user's eye for a data trigger arrangement. The method includes obtaining first image data within a first vision field of a first data capturing sensor. The method includes determining a first area viewed by a user's eye as a function of the first image data. The method includes obtaining second image data within a second vision field of a second sensor. The method includes determining a second area captured within the second field of vision as a function of the second image data. The method includes determining disposition data of the first area within the second area. When a trigger command is captured, the method includes data capturing a machine readable representation of data (MRRoD) using the second sensor as a function of the disposition data.

Abstract: Circuitry of a gaze/eye tracking system obtains one or more images of a left eye and one or more images a right eye, determines a gaze direction of the left eye based on at least one obtained image of the left eye, determines a gaze direction of the right eye based on at least one obtained image of the right eye, determines a first confidence value based on the one or more obtained images of the left eye, determines a second confidence value based on the one or more obtained images of the right eye, and determines a final gaze direction based at least in part on the first confidence value and the second confidence value. The first and second confidence values represent indications of the reliability of the determined gaze directions of the left eye and the right eye, respectively. Corresponding methods and computer-readable media are also provided.

Abstract: The present disclosure describes compact remote eye tracking systems that include depth sensing capacity. In one aspect, a method of eye tracking includes illuminating a subject's eye with illumination; detecting, in a depth sensor, optical signals reflected from the subject's face in response to the illumination; generating a depth map based on the optical signals detected by the depth sensor; acquiring an intensity image based on optical signals reflected from the subject's face in response to the illumination; determining, based on a portion of the depth map corresponding to the subject's eye, an estimated distance between the subject's eye and a target screen; determining an estimated gaze direction of the subject's eye based on information obtained from the intensity image; and determining, based on the estimated gaze direction and the estimated distance between the subject's eye and the target screen, a gaze point for the subject's eye.

Abstract: A subject (180) is illuminated whose movements of at least one eye are to be registered by an eye-tracker for producing resulting data (DEYE). To this aim, a coherent light source in light producing means (140) produces at least one well-defined light beam (L1, L2). A diffractive optical element is arranged between the coherent light source and an output from the light producing means (140). The diffractive optical element is configured to direct a light beam (L1) towards at least a first designated area (A1) estimated to cover the at least one eye of the subject (180). Image registering means (150) registers light from the at least one light beam (L1, L2) having been reflected against the subject (180). The resulting data (DEYE) are produced in response to these light reflections, which resulting data (DEYE) represent movements of the at least one eye of the subject (180).

Abstract: The invention is directed to systems, methods and computer program products for gaze tracking. An exemplary method includes directing light into an eye using a projector; detecting, using an image-capturing module, a reflection from a surface associated with the eye; and determining a line of sight associated with the eye based on the detected reflection. In some embodiments, the light comprises infra-red light. In some embodiments, the projector comprises a laser. In some embodiments, the projector comprises a liquid crystal on silicon (LCoS) chip. In some embodiments, the surface associated with the reflection is at least one of the cornea, the iris, or the retina.

Abstract: Smart eyeglasses with iris recognition device comprise at least one glasses frame, a glasses arm connected to a side of the glasses frame; an iris recognition device installed on the glasses frame and having a recognition unit facing an inner side of the glasses frame. A light source device installed on the glasses frame projects a light on an inner side of an outer boundary of an iris of an eyeball, and not in contact with the outer boundary of the iris. The iris is sampled more easily and clearly with luminosity compensation of the light source device for enhancing the accuracy and sampling speed.

Abstract: A pupil detection light source device includes an aperture disposed to face a subject to allow light from a pupil of the subject to pass therethrough, an illumination light for obtaining a light pupil image toward the subject from the inside or the vicinity of the aperture when seen from the subject, and an illumination light for forming a reflection image with glasses obtained by canceling a reflection image with glasses of the light pupil image using an image difference toward the subject from the inside or the vicinity of the aperture when seen from the subject.

Abstract: A motor vehicle operating device has a display device, an operating element and a control device, which are mutually coupled and set up such that an operating element symbol that corresponds to the operating element with respect to its outline shape is displayed on the display device. Navigation through a hierarchical menu structure displayed on the display device can take place or takes place by use of the operating element. The operating element can be operated corresponding to a plurality of operating degrees of freedom. Different groups of operating degrees of freedom are enabled for the navigation at different locations of the hierarchical menu structure. Those operating degrees of freedom enabled at the current location of the menu structure are displayed on or at the operating element symbol.

Abstract: There is provided an information processing device including: a gaze position acquisition unit configured to acquire a gaze position of a user; a determination unit configured to determine whether the acquired gaze position corresponds to an application-related position; and a processing unit configured, when the gaze position is determined to correspond to the application-related position, to control a state of an application.

Abstract: In a color imaging system, multiple rendering devices are provided at different nodes along a network. Each rendering device has a color measurement instrument for calibrating the color presented by the rendering device. A rendering device may be a printer in which the measuring of color samples on a sheet rendered by the printer is provided by a sensor coupled to a transport mechanism which moves the sensor and sheet relative to each other, where the sensor provides light from the samples to a spectrograph. A rendering device may also be a display having a member supporting a color measuring instrument for receiving light from an area of the screen. The color measuring instruments provide for non-contact measurements of color samples rendered on a display or a sheet, and are self-calibrating by the use of calibration references.

Abstract: At least one image registering unit records at least one series of images representing a subject. A control unit controls an operation sequence for the at least one image registering unit in such a manner that a subsequent data processing unit receives a repeating sequence of image frames there from, wherein each period contains at least one image frame of a first resolution and at least one image frame of a second resolution being different from the first resolution. Based on the registered image frames, the data processing unit produces eye/gaze tracking data with respect to the subject.

Abstract: Methods for improving gaze tracking are presented. These methods eliminate the need for a separate initial calibration step to determine whether the subject is properly centrally fixated during testing. In one embodiment, whether the subject is centrally fixated is determined by identifying inlier and outlier gaze descriptors; the inliers are assumed to be associated with central fixation. This reduces the total time required for testing. These methods also improve the accuracy of gaze tracking during testing without the need for individual subject calibration. Instead, a database of reference eyes is used. The subject's eye can be compared to the reference eyes, and the mapping function for one or more reference matches can be used to estimate the subject's gaze direction. In another embodiment, previous calibration data from the same subject can be used to determine whether the subject is properly centrally fixated and/or the direction of the subject's gaze.

Abstract: The invention relates to a method and device for determining eye position, wherein a light pattern is produced on the surface of an eye by means of a light source and an image of the light pattern produced on the eye is recorded by means of an image recording apparatus, wherein points of the transition region between the sclera and the iris of the eye are determined from the image of the light pattern by means of an image processing apparatus. The coordinates of the calculated points are calculated by triangulation or stereovision, and the position of the iris plane or a plane oriented parallel thereto is determined from said coordinates. The limbus of the eye and the center thereof can also be determined in three dimensions.

Abstract: A human-machine interface (HMI) system used to indicate a vehicle-feature based on glance-direction of an occupant of the vehicle includes a camera and a controller. The camera is used to capture a sequence-of-images of an occupant of a vehicle. The controller is configured to determine a plurality of glance-directions from the sequence-of-images, define a plurality of glance-zones based on the plurality of glance-directions, one glance-zone for each glance-direction, define an intersection-zone based on an intersection of two or more of the glance-zones, determine an outlier-count based on how many of the plurality of glance-zones do not intersect with the intersection-zone, and select a vehicle-feature in the vehicle indicated by the occupant, said vehicle-feature located at a location inside the vehicle that corresponds to the intersection-zone, said vehicle-feature indicated by the operator when the outlier-count during the pause-interval is less than a paused-threshold.

Abstract: A 3D holographic virtual object display controlling method and apparatus based on human-eye tracking are provided. The display controlling method comprises the following steps of: activating tracking of human eyes of a user; tracking motions of eyeballs of the user; controlling a 3D holographic virtual object presented in a display interface to rotate in response to the motions of the eyeballs of the user; and ending up the tracking of the human eyes of the user. Thereby, the present disclosure can control rotation of a 3D holographic virtual object presented in a display interface by tracking eyeballs and in response to the motions of the eyeballs, which makes the operations convenient and easy.

Abstract: A display device includes an image display section adapted to display an image so as to be able to be visually recognized together with an outside view, a camera, and a control section adapted to process taken image data of the camera, and the control section selects a mode as a processing condition, which corresponds to whether or not display is performed in the image display section based on taken image data, to process the taken image data.

Abstract: Efficient interferometer designs for optical coherence tomography (OCT) systems are presented. One example interferometer design includes two polarization dependent beamsplitters and a non-polarization dependent combiner. The first polarization dependent beamsplitter transmits light in a first polarization state to a sample arm of the OCT system and transmits light in a second polarization state different from the first polarization state to a reference arm of the system. The second polarization dependent beamsplitter transmits light returning from a sample to the non-polarization dependent combiner. The combiner combines light returned from the sample and the light that has passed through the reference arm, which is then detected at a detector. Another example interferometer design includes free space optics comprising a non-reciprocal beamsplitting element in a beam path from a light source to a sample.

Abstract: A system for tracking the 3D position and gaze angles of the eyes over their full range of movement in space relative to a camera or relative to the head without the need for calibration or specialized image aquisition equipment. The eyes are tracked on the basis of surface features in relation to a geometrical 3D model of the eyes by means of a standard consumer device for recording the sequence of face images in conjunction with computing capability. The resultant eye positions and pupil diameters are used to control the information on a viewing screen or in another device. The system further allows for deriving the angular trajectories of the eye movements and for fitting model functions of these trajectories to characterize the degree of normality and deviation from normality of the binocular eye movement parameters.

Abstract: The invention provides an image capture system, apparatus and method for capturing a biometric image in high ambient light environments. Reflections from ambient light can introduce unwanted environmental pattern noise that can interfere with extracting information from a captured biometric image. The invention performs attenuation of ambient light without requiring employment of shielding to prevent ambient light from reflecting off of a surface being imaged. As a result, the invention can be deployed into environments with varied indoor or outdoor lighting characteristics.

Abstract: A device is for imaging an eye and is wearable on the object to be examined or otherwise able to be placed to the front of an eye or eyes. When the device is switched on, it automatically performs the imaging such that all images are useful. The device comprises a camera arrangement with optics and a camera sensor, and an illumination arrangement. The device comprises a control arrangement that switches the camera arrangement to take automatically one or more images of the eye, when the device is in front of the eye. The device comprises an image analyzing arrangement or a connection to an image analyzing arrangement that is provided for detecting a reflection in the image taken by the camera arrangement or in the image area of the camera arrangement and for transmitting the information about the detected reflection to the control arrangement which is provided thereby to repeat or decline imaging. When repeating the imaging the control arrangement alters the parameters of imaging.

Abstract: The present invention is a method and system for rating in-store media elements based on the measurement for behavior patterns and demographics of the audience in the vicinity of the media element, where a plurality of input images of the audience are captured by at least a means for capturing images in the vicinity of the media element. The input images are processed by automated video analytic algorithms in order to measure the behavior patterns and demographics of each person in the audience tied to the media element. The measurements for the behavior patterns and demographics of the audience from the target media elements are aggregated. A set of ratings for the media element is calculated based on the measurements. The measured media elements are sampled, and the audience measurement for the sample is extrapolated to other media elements for in-store locations or for a group of stores. The ratings are converted into a standardized output.

Abstract: Systems and methods for assessing human reaction to a stimulus using computer vision are described herein. A computer can compare a first facial image with a second facial image to identify a region of a subject's face where an expressional repositioning is evident. Based on the expressional repositioning, the computer can determine an emotion exhibited by the subject.

Abstract: Technologies for power optimization of light sources include an imaging device to generate a captured image of a subject. The imaging device analyzes the captured image to determine, in the captured image, a location of the subject's eye relative to the imaging device, an iris-pupil contrast of the subject's eye, and a glint intensity of glints present on the subject's eye. The imaging device determines, for each of a plurality of light sources, an illumination efficiency based on a distance between the camera and the subject's eye, a distance between the light source and the subject's eye, an incidence angle of the light source relative to the subject's eye, and a power profile of the light source. The imaging device determines an amount of power to supply to each light source to reduce a total cumulative power supplied to the light sources based on one or more power constraints.