Apparatus and methods for interactive illumination

• US 8,593,073 B2
• Filed: 10/15/2010
• Issued: 11/26/2013
• Est. Priority Date: 10/15/2009
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Aldrich, Matthew, Feldmeier, Mark, Paradiso, Joseph
• Primary Examiner(s): A, Minh D
• Application Number:
  US12/905,968
• Publication Number:
  US 20110089842A1
• Time in Patent Office: 1,138 Days
• Field of Search: 315/291, 315/307, 315/292, 315/185.R, 315/192, 315/247, 315/312, 315/293, 315/317, 315/318, 315/DIG.4
• US Class Current: 315/291
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/175 by remote control
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

In illustrative implementations of this invention, a lighting system comprises a plurality of LEDs, fluorescent lights, incandescent lights, a processor, a sensor node and a human-computer interface. The sensor is adapted to be moved by a user and placed in the location that a user wants to illumine. The LED lights are adapted to emit pulse-width modulated (PWM) light, controlled by signals from the processor. The lighting system is adapted to optimize parameters (such as efficacy or color rendering index) selected by the user, subject to certain constraints (such as desired illuminance or color temperature). According to principles of this invention, if a sensor is moved, attenuation may be measured and the inverse square law may be used to determine how constraints in an optimization algorithm need to be updated.

Claims

1. A lighting control system comprising, in combination:

(a) a light sensor; and

(b) one or more processors;

wherein the one or more processors are configured to;

(i) to optimize a parameter regarding lighting,

(ii) to calculate how to adjust outputs of respective light sources to maximize or minimize the parameter,

(iii) to update a constraint in an optimization algorithm, after the sensor has been moved relative to a light source to a new position, by (A) taking a measurement of incident intensity at the new position, (B) calculating attenuation, by comparing the measurement to a reference value at a known distance from the light source, and (C) using the inverse square law to calculate a change in the constraint of the optimization algorithm.

2. The system of claim 1, wherein the system is further adapted to update outputted control instructions in real time, in response to a constraint of the optimization algorithm being changed by input from a user.

3. The system of claim 1, wherein:

(a) the sensor is configured to take measurements of intensity of infrared light from a light source incident at a target position; and

(b) the one or more processors are configured

(i) to calculate, based on the measurements, intensity of visible light from the light source incident at the target position, and

(ii) to calculate contribution by the light source to total illuminance at the target position, which total illuminance is from a plurality of light sources.

4. The system of claim 1, wherein

a) the sensor is configured to measure amplitude of a carrier frequency at a sensor position, which carrier frequency comprises part of PWM light emitted by a light source, is higher than the fundamental frequency of the PWM light, and uniquely identifies the light source;

and

(b) the one or more processors are configured

(i) to estimate, based on the amplitude of the carrier frequency, visible light amplitude, and

(ii) to determine contribution of the light source to total illuminance at the sensor position, which total illuminance is from a plurality of light sources.

5. The lighting control system of claim 1, wherein the lighting control system is configured:

(5a) to measure incident intensity at a sensor position during an initial lighting state;

(5b) to output instructions for causing a change in emitted intensity of a plurality of light sources, which change is to a new lighting state and is by a known percentage, in such a way that emitted intensity is increased for a first subset of the plurality of the light sources and decreased for a second subset of the plurality of the light sources;

(5c) to measure incident intensity at the sensor position during the new lighting state;

(5d) to repeat steps (5a), (5b) and (5c) for different subsets of the plurality of the light sources, until a system of linear equations is specified, and

(5e) to solve the system of linear equations to determine contributions of respective light sources, out of the plurality, to a total incident intensity at the sensor position.

6. The system of claim 1, wherein the sensor is configured to be carried by a human user.

7. The system of claim 1, wherein at least one actuator is adapted to move at least one said sensor continuously or periodically through or in an area or volume.

8. The system of claim 1, wherein the parameter comprises efficacy or CRI.

9. A lighting system comprising, in combination:

(a) a plurality of PWM illumination sources;

(b) a light sensor for measuring intensity of light; and

(c) at least one processor for

(i) calculating light intensity contributed by respective illumination sources, out of a plurality of illumination sources, at a point of incidence;

(ii) calculating the light intensity of each of the respective illumination sources needed to optimize an attribute of said system, subject to one or more constraints; and

(iii) outputting instructions for controlling the illumination sources;

wherein the system is adapted (1) to update the optimization calculations and the outputted instructions in real time, in response to the light sensor being repositioned relative to the illumination sources, and (2) to update the optimization calculations and the outputted instructions in real time, in response to a specified constraint, out of the one or more constraints, being changed by input from a user.

10. The system of claim 9, wherein the at least one processor is adapted to process measurements of primarily reflected light in order to update a constraint or objective function in a linear computing optimization.

11. The system of claim 9, wherein the specified constraint is a value that represents a user preference regarding lighting intensity.

12. The system of claim 9, wherein the specified constraint is a value that represents a user preference regarding color.

13. The system of claim 9, wherein at least some of the PWM illumination sources comprise a polychromatic set of LED active emitters.

14. The system of claim 9, wherein:

(a) the light sensor is one of a plurality of light sensors;

(b) the system further comprises the plurality of light sensors;

(c) each respective sensor, out of the plurality of sensors, is substantially co-located with one of the illumination sources; and

the at least one processor is adapted

(i) to process data regarding light intensity measurements taken by the plurality of sensors,

(ii) to calculate respective light maps for the illumination sources,

(iii) to superimpose the light maps on each other to calculate a model of a lighting space, and

(iv) to calculate light intensity contributed by the respective illumination sources at a point of incidence.

15. The system of claim 9, wherein the sensor is adapted for being carried or worn by a human user.

16. The system of claim 9, wherein the sensor is housed with at least one infrared motion detection sensor or with at least one accelerometer.

17. The system of claim 9, wherein the attribute that is optimized is efficacy or CRI.

18. The system of claim 9, wherein at least one actuator is adapted to move the sensor continuously or periodically through or in an area or volume.

19. A method for controlling lights comprising the following steps, in combination:

(a) using a light sensor to measure intensity of light; and

(b) using at least one processor

(i) to calculate light intensity contributed by respective light sources, out of a plurality of light sources, at a point of incidence,

(ii) to calculate light intensity of each of the respective light sources needed to optimize an attribute of said system, subject to one or more constraints,

(iii) to output instructions for controlling the light sources, and

(iv) to update the optimization calculations and the outputted instructions in real time, in response to the light sensor being repositioned relative to the illumination sources.

20. The method of claim 19, further comprising the step of changing, in real time, a specified constraint out of the one or more constraints in response to input from a user.