Method and apparatus for correcting light

• US 8,737,731 B2
• Filed: 12/15/2011
• Issued: 05/27/2014
• Est. Priority Date: 12/16/2010
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Park, Seong Hee, Kim, Insu, Kang, Tae-Gyu
• Primary Examiner(s): PATEL, KANJIBHAI B
• Application Number:
  US13/327,005
• Publication Number:
  US 20120153837A1
• Time in Patent Office: 894 Days
• Field of Search: 382/162, 382/167, 382/276, 382/305, 382/312, 382/274, 315/151, 315/247, 345/30, 345/80, 345/82, 345/84, 345/88, 362/84, 362/97.1, 362/97.2, 362/97.3, 362/642
• US Class Current: 382/167
• CPC Class Codes: H05B 45/22 using optical feedback

Abstract

Light emitted from a lighting device including a white LED and RGB LEDs is sensed when the lighting device is driven based on a predetermined reference value, sensed data is converted into values corresponding to color coordinates, and a difference between the value and a reference value is calculated. It is determined whether or not the lighting device is corrected on the basis of the calculated difference, and the lighting device is selectively corrected depending on the determination result.

Claims

1. A method for correcting a lighting device, comprising:

sensing light emitted from the lighting device when the lighting device is driven and generating sensing data including RGB values corresponding to the sensed light;

converting the sensing data into measured color coordinate values corresponding to color coordinates;

calculating differences between the measured color coordinate values corresponding to the sensing data and reference color coordinate values used when the lighting device is driven; and

correcting the reference color coordinate values on the basis of the calculated differences; and

comparing the differences with predetermined allowances to determine whether or not to perform correction, and performing a delay process for delaying the correction when it is determined that the correction is not to be performed,

wherein the color coordinate values are composed of x, y, and z, and the differences include a first difference corresponding to a difference between an x value of the measured color coordinate values corresponding to the sensing data and an x value of the reference color coordinate values, a second difference corresponding to a difference between a y value of the measured color coordinate values corresponding to the sensing data and a y value of the reference color coordinate values, and a third difference corresponding to a difference between a z value of the measured color coordinate values corresponding to the sensing data and a z value of the reference color coordinate values.

2. The method of claim 1, wherein the determining of whether or not to perform correction comprises:

respectively comparing the first, second, and third differences with first, second, and third allowances; and

determining that correction is not to be performed if any of the first, second, and third differences exceed the corresponding allowance.

3. The method of claim 2, wherein the determining of whether or not to perform correction further comprises performing correction when all of the first, second, and third differences do not exceed the corresponding allowances.

4. The method of claim 2, wherein the first, second, and third allowances have the same value.

5. The method of claim 2, wherein the performing of the delay process repeats a process of acquiring the sensing data for a predetermined period, and includes calculating the differences and comparing the differences with the corresponding allowances a predetermined number of times.

6. The method of claim 5, wherein the performing of the delay process finishes a correction operation if any of the first, second, and third differences exceed the corresponding allowance even though the process has been repeated the predetermined number of times for the predetermined period.

7. The method of claim 2, wherein the correcting of the reference color coordinate values comprises:

adding or subtracting the first difference to or from the x value of the reference color coordinate values;

adding or subtracting the second difference to or from the y value of the reference color coordinate values; and

adding or subtracting the third difference to or from the z value of the reference color coordinate values.

8. The method of claim 7, wherein when the first, second, and third differences are greater than “

0”

, a correction operation of adding the differences is performed, and when the first, second, and third differences are smaller than “

0”

, a correction operation of subtracting the differences is performed.

9. An apparatus for correcting a lighting device, comprising:

a sensing unit that senses light emitted from the lighting device when the lighting device is driven and generating sensing data including RGB values corresponding to the sensed light; and

a correction unit that corrects reference color coordinate values corresponding to color coordinates used when the lighting device is driven using the sensing data,

wherein the correction unit comprises;

a conversion module that converts the sensing data into measured color coordinate values corresponding to color coordinates;

a calculation module that calculates differences between the measured color coordinate values corresponding to the sensing data and the reference color coordinate values used when the lighting device is driven; and

a correction module that corrects the reference color coordinate values on the basis of the calculated differences,

wherein the color coordinate values are composed of x, y, and z, and the differences include a first difference corresponding to a difference between an x value of the measured color coordinate values corresponding to the sensing data and an x value of the reference color coordinate values, a second difference corresponding to a difference between a y value of the measured color coordinate values corresponding to the sensing data and a y value of the reference color coordinate values, and a third difference corresponding to a difference between a z value of the measured color coordinate values corresponding to the sensing data and a z value of the reference color coordinate values.

10. The apparatus of claim 9, wherein the correction module performs a process for comparing the differences with predetermined allowances, determining whether or not to perform correction, and performing a delay process for delaying the correction when determining that the correction is not to be performed.

11. The apparatus of claim 9, wherein the delay process repeats a process of acquiring the sensing data for a predetermined period, calculating the differences, and comparing the differences with corresponding allowances a predetermined number of times.

12. The apparatus of claim 9, wherein the correction module respectively compares the first, second, and third differences with first, second, and third allowances, and determines that correction is not to be performed when any of the first, second, and third differences exceeds the corresponding allowance.

13. The apparatus of claim 9, wherein the correction module performs one of a correction operation of adding the first difference to the x value of the reference color coordinate values, a correction operation of adding the second difference to the y value of the reference color coordinate values, and a correction operation of adding the third difference to the z value of the reference color coordinate values when one of the first, second, and third differences exceeds “

0”

, and carries out one of a correction operation of subtracting the first difference from the x value of the reference color coordinate values, a correction operation of subtracting the second difference from the y value of the reference color coordinate values, and a correction operation of subtracting the third difference from the z value of the reference color coordinate values when one of the first, second, and third differences is smaller than “

0”

.

14. The apparatus of claim 9, wherein the sensing unit is located between the lighting device and a diffuser and is configured with a sensor that outputs RGB values including an R value, a G value, and a B value that respectively correspond to an R component, a G component, and a B component of the light emitted from the lighting device.

15. The apparatus of claim 9, wherein the lighting device includes a white light emitting diode (LED) and red, green, blue (RGB) LEDs.