Abstract: Introduced here are light sources for flash photography configured to produce high-fidelity white light that is tunable over a broader range of correlated color temperatures (CCTs) than conventional flash technologies. The light source can include multiple independently controllable color channels representing illuminants (e.g., light-emitting diodes) of different colors with varying degrees of saturation. Operating collectively, the multiple color channels can produce a high spectral quality white light corresponding to different CCTs (e.g., “warm” white light having a red hue, “cool” white light having a blue hue). Operating independently, these same color channels can be pre-flashed in a variety of prescribed sequences to probe the spectral characteristics of a scene, thereby allowing for an enhanced, spectrally matched white flash as well as collecting per-pixel reflectivity data that can be later used in during post processing of the captured image.

Abstract: Introduced here are computer programs and associated computer-implemented techniques for determining reflectance of an image on a per-pixel basis. More specifically, a characterization module can initially acquire a first data set generated by a multi-channel light source and a second data set generated by a multi-channel image sensor. The first data set may specify the illuminance of each color channel of the multi-channel light source (which is configured to produce a flash), while the second data set may specify the response of each sensor channel of the multi-channel image sensor (which is configured to capture an image in conjunction with the flash). Thus, the characterization module may determine reflectance based on illuminance and sensor response. The characterization module may also be configured to determine illuminance based on reflectance and sensor response, or determine sensor response based on illuminance and reflectance.

Abstract: Some embodiments include a method of operating a tunable light module. The method can include driving a lamp in the tunable light module, having lamps of at least two colors, to produce a colored light according to the color mixing plan that corresponds to a correlated color temperature (CCT); measuring a light characteristic of the lamp using a light sensor; detecting a degradation level by comparing the measured light characteristic against an expected light characteristic; and adjusting a current level for driving the lamp at the CCT by referencing the color mixing plan and an alternative coefficient corresponding to the degradation level.

Abstract: Various embodiments relate to systems and methods for controlling one or more LED-based lighting sources that are coupled to a logic module by a ribbon cable. The ribbon cable allows some or all of the processing components (e.g., processors and drivers) to be decoupled from the LED-based lighting source(s). The processing components can instead be housed within the logic module, which is able to simultaneously control the LED-based lighting source(s). Together with color models established for each LED board, the logic module acts as a platform for modularity and is able to more precisely control the color channels of each LED-based lighting source using the color models established for those LED-based lighting source(s). Techniques are also described herein that allow the logic module to utilize data stored within an erasable programmable read-only memory (EPROM) that describes the color characteristics of an LED-based lighting source.

Abstract: Various embodiments are described herein that relate to systems and methods for selectively providing current to power LEDs. The techniques introduced here can enable smooth dimming of the LEDs from maximum brightness down to “actual extinction” or “pseudo-extinction.” More specifically, the LEDs can be dimmed to extinction without any significant gaps in the levels of brightness (i.e., a noticeable drop rather than a smooth transition between brightness levels). Various pulse width modulation (PWM) and shunting techniques may be used to control the power provided to each color channel of an LED board. Conventionally, PWM often causes LEDs to produce an undesirable acoustic effect. However, by dithering the PWM signals between multiple predetermined positions once the frequency enters the audible range (e.g., below 25 kHz), the cumulative acoustic effect instead becomes white noise.

Abstract: An electrical circuit is disclosed and methods for controlling the same. The electrical circuit may comprises a plurality of color strings coupled in series, where each color string has at least one lamp, preferably a light emitting diode. Improved efficiency may be accomplished in some embodiments using certain of the disclosed systems and methods.

Abstract: Some embodiments include a method of operating a tunable light module. The method can include driving a lamp in the tunable light module, having lamps of at least two colors, to produce a colored light according to the color mixing plan that corresponds to a correlated color temperature (CCT); measuring a light characteristic of the lamp using a light sensor; detecting a degradation level by comparing the measured light characteristic against an expected light characteristic; and adjusting a current level for driving the lamp at the CCT by referencing the color mixing plan and an alternative coefficient corresponding to the degradation level.

Abstract: Some embodiments include a model builder system that generates a color model to facilitate a color tunable lamp to mix the right amount of light from various color channels to reproduce a target color characteristic of a reference lamp. The model builder system can perform pre-computations that characterize the perceived characteristic of individual color channels and the reference lamp. The model builder system can divide the color channels of the color tunable lamp into floating channels and non-floating channels. Holding the operating points of the non-floating channels constant, the model builder system inverse solves for the necessary flux values of the color channels to reproduce the target color characteristic and to optimize color metrics.

Abstract: Light source systems and methods of operating the light source systems are disclosed. A light source system may include a combination of two lighting modules in communication with each other. The lighting modules can operate in concert, in parallel, or as master or slave. A printed circuit board assembly (PCBA) of the light source system includes electrical circuitry to drive a set of light emitting diodes (LEDs). The PCBA can include a communication interface for communication amongst the lighting modules. The PCBA can also include an optical sensor to provide color spectrum feedback to a controller module for self calibration. A master PCBA can receive sensor feedbacks, such as thermal and optical feedbacks from a slave PCBA. The sensor feedbacks can then be used to tune a color spectrum of a slave lighting module including calibrating the slave lighting module.

Abstract: Some embodiments include a model builder system that generates a color model to facilitate a color tunable lamp to mix the right amount of light from various color channels to reproduce a target color characteristic of a reference lamp. The model builder system can perform pre-computations that characterize the perceived characteristic of individual color channels and the reference lamp. The model builder system can divide the color channels of the color tunable lamp into floating channels and non-floating channels. Holding the operating points of the non-floating channels constant, the model builder system inverse solves for the necessary flux values of the color channels to reproduce the target color characteristic and to optimize color metrics.

Abstract: Systems and methods for using an expert system to develop a color model for and LED-based lamp for reproducing a target light and calibrating the lamp are disclosed. The CCT of light generated by the lamp is tunable by adjusting the amount of light contributed by each of the LED strings in the lamp. The target light is decomposed into different wavelength bands, and light generated by the LED-based lamp is also decomposed into the same wavelength bands and compared. A color model for the lamp provides information on how hard to drive each LED string in the lamp to generate light over a range of CCTs, and the color model is used to search for the appropriate operating point of the lamp to reproduce the target light.

Abstract: A linear light source and a method of manufacturing the linear light source are disclosed. The linear light source includes a light emitting diode (LED) array, a light pipe, and a shell with a linear exit slit aperture. Cutouts of the light pipe provides a slanted surface to reflect portions of light rays along the length of the light pipe out of the linear exit slit aperture.

Abstract: Lighting and control systems and methods for a lighting node and a remote control device are disclosed. The remote control device may be coupled to the lighting node via an identification process, such as broadcasting an identification request from the remote control device to nearby lighting nodes. The lighting node can respond to the identification request by sending an identifier to the remote control device such that future commands sent from the remote control device is limited to be responded by the lighting node having the identifier stored thereon. Once coupled, the remote control device can adjust spectral content produced by the lighting node based on user-configuration or a color profile captured via an optical sensor. The adjustment via the remote control device may further include calibration and recalibration of the lighting node utilizing a feedback mechanism with the optical sensor.

Abstract: A lighting system comprising multiple linear lighting module building blocks is described. A lighting module is designed to emit light in a linear configuration, and multiple lighting modules are concatenated to emit light in a single linear configuration. A mechanical coupling system allows the lighting modules to be inserted into the linear configuration from a direction perpendicular to the linear configuration. The housing of the lighting modules is designed to allow the module to be clipped together in the linear configuration.

Abstract: A phase change material (PCM) is used for thermal storage for LED-based lighting systems. The PCM is placed in multiple sealed containers in thermal contact with the LED to be cooled. The PCM is selected such that its melting point temperature is substantially the preferred operating temperature of the LED. When the LED is on, the PCM absorbs and stores some of the heat generated by the LED, while some of the generated heat is convected away from the LED. The PCM is selected based upon its heat storage capabilities to cool the LED when the lighting system is operated for a cyclical application.

Abstract: Systems and methods for using an LED-based lamp for reproducing a target light are disclosed. A color-space searching technique is introduced here that enables the LED-based lamp to be tuned to generate light at a specific CCT by adjusting the amount of light contributed by each of the LED strings in the lamp. The target light is decomposed into different wavelength bands, and light generated by the LED-based lamp is also decomposed into the same wavelength bands and compared. The color-searching techniques allow the LED-based lamp to closely emulate a black body radiator given the limitations of the physical specification of color string in the LED strings.

Abstract: A mobile application is disclosed that allows a user to configure an LED-based lamp. The LED-based lamp has the capability of color matching color spectrums and calibrating its correlated color temperatures, brightness, and hue based on a color model. The mobile application can send or schedule commands actively or passively to activate the color matching and calibration process on the LED-based lamp. The mobile application can further receive status information regarding the LED-based lamp including fault detection, estimated life time, temperature, power consumption, or any combination thereof.

Abstract: The tunable color mixing system includes a mixing barrel that captures light from multiple light emitting diodes emitting at different colors, mixes the light, and outputs the light with a narrow beam angle from a small area. The array of LEDs in the system is thermally coupled to a heat conductor via thermal pads. A flexible printed circuit is electrically connected to the LEDs to supply and fine-tune the electrical power. The array includes LEDs of at least three emitting colors to achieve an output light having a high color rendering index, tunable to a wide range of correlated color temperatures.

Abstract: An electrical circuit is described that comprises a first string and second LED string coupled in parallel, a first and second transistor, at least one bypass transistor, and a controller. The first transistor is coupled to the first LED string at a first terminal of the first transistor. The second LED string includes multiple LED color strings coupled in series. The second transistor is coupled to the second LED string at a first terminal of the second transistor. The bypass transistor is coupled to one of the color strings. A first terminal of the bypass transistor is coupled to a first terminal of the color string. The second terminal of the bypass transistor is coupled to a second terminal of the color string. The controller controls a gate voltage of the first and second transistors and the bypass transistor to operate all transistors in linear modes.

Abstract: A lighting node is described. One embodiment of the lighting node includes a lamp, a radio device, and a memory. The lamp is configured for generating illumination. The radio device is configured for radio communication. The radio device is configured to remotely receive a color profile from the controller. The lamp is also configured to generate illumination to substantially match the received color profile. The memory is configured to store a group identifier for the lighting node.