Determining an ambient light unit vector and an ambient light intensity value using a sensor behind display

Patent metadata

Field	Value
Publication number	US-12163839-B2
Application number	US-202017617722-A
Country	US
Kind code	B2
Filing date	Jul 16, 2020
Priority date	Jul 26, 2019
Publication date	Dec 10, 2024
Grant date	Dec 10, 2024

Abstract

The present disclosure describes a method and apparatus that can be used to determine various characteristics of ambient light when an ambient light sensor is located behind a display screen. The strategy of the disclosure relies, at least in part, on spectral decomposition of ambient light measurements into components (e.g., red, green, and blue components of an Organic Light Emitting Diode (“OLED”) display screen and ambient light). Following the spectral decomposition technique, statistical analysis are performed on the measurement data to remove the OLED light components from the measurement. This technique enables determinations such as ambient lux and correlated color temperature independent of the content displayed on the screen.

First claim

The invention claimed is:

1. An apparatus comprising:
a display screen;
a memory;
an ambient light sensor disposed behind the display screen; and
an electronic control unit operable to:
receive ambient light measurements for a plurality of optical channels of the ambient light sensor, the ambient light measurements taken over a time interval;
retrieve, from the memory, reference data generated based on prior measurements for the plurality of optical channels, wherein the prior measurements are for the display screen;
determine, based on the measurement data and the reference data for measurements during the time interval, a first set of intensity data corresponding to a first color component of an image on the display screen, a second set of intensity data corresponding to a second color component of the image on the display screen, a third set of intensity data corresponding to a third color component of the image on the display screen, and a fourth set of intensity data corresponding to an estimate of intensity of ambient light;
determine, using statistical correlation between the first set and the fourth set, a first dataset corresponding to a red color component of ambient light;
determine, using statistical correlation between the second set and the fourth set, a second dataset corresponding to a green color component in the ambient light;
determine, using statistical correlation between the third set and the fourth set, a third dataset corresponding to a blue color component in the ambient light; and
calculate, based on the first dataset, the second dataset, and the third dataset, an ambient light unit vector and an ambient light intensity value.

2. The apparatus of claim 1 , wherein the first color component is a red color component of the image on the display screen, the second color component is a green color component of the image on the display screen, and the third color component is a blue color component of the image on the display screen.

3. The apparatus of claim 2 , wherein the electronic control unit is operable to receive ambient light measurements from the ambient light sensor over a time period by:
receiving, at a first time of the time interval, a first plurality of light measurements for a plurality of optical channels of the ambient light sensor;
storing the first plurality of light measurements with the first time;
receiving, at a second time of the time interval, a second plurality of light measurements for the plurality of optical channels of the ambient light sensor; and
storing the second plurality of light measurements with the second time.

4. The apparatus of claim 3 , wherein the electronic control unit is further operable to generate, based on the ambient light measurements, a plurality of vectors for a plurality of times during the time interval, wherein each vector of the plurality of vectors includes a plurality of measurement values, each measurement value corresponding to an intensity value recorded by a corresponding optical channel of the ambient light sensor.

5. The apparatus of claim 4 , wherein the electronic control unit is operable to retrieve, from the memory, reference data generated based on the prior measurements by retrieving a red component reference unit vector, a green component reference unit vector, and a blue component reference unit vector, wherein each retrieved reference unit vector comprises a plurality of unit intensity values for each of the plurality of optical channels.

6. The apparatus of claim 5 , wherein the electronic control unit is operable to determine the first set of intensity data, the second set of intensity data, the third set of intensity data, and the fourth set of intensity data by calculating, based on the reference data and the ambient light measurement data using a set of equations, a plurality of red component intensity vectors, a plurality of green component intensity vectors, a plurality of blue component intensity vectors, and a plurality of ambient light component intensity vectors.

7. The apparatus of claim 6 , wherein the electronic control unit is operable to determine, the first dataset corresponding to the red color component of the ambient light by: calculating, for the first dataset, a first plurality of metrics, wherein each of the first plurality of metrics is determined using a red component intensity vector and an ambient light component intensity vector that was received at a same time as the corresponding red component intensity vector;
for each metric:
in response to determining that the metric is less than zero setting a scalar value to a negative number; and
in response to determining that the metric is greater than zero setting the scalar value to a positive number;
iteratively adding each scalar to a given light component intensity vector; and
determining a red light component intensity vector based on result of iteratively adding each scalar to the given light component intensity vector.

8. The apparatus of claim 7 , wherein the electronic control unit is operable to determine, the second dataset corresponding to the green color component of the ambient light by:
calculating, for the second dataset, a second plurality of metrics, wherein each of the second plurality of metrics is determined using a green component intensity vector and an ambient light component intensity vector that was received at a same time as the corresponding green component intensity vector;
for each metric:
in response to determining that the metric is less than zero setting a scalar value to a negative number; and
in response to determining that the metric is greater than zero setting the scalar value to a positive number;
iteratively adding each scalar to a given light component intensity vector; and

determining a green light component intensity vector based on result of iteratively adding each scalar to the given light component intensity vector.

9. The apparatus of claim 8 , wherein the electronic control unit is operable to determine, the third dataset corresponding to the blue color component of the ambient light by: calculating, for the third dataset, a third plurality of metrics, wherein each of the third plurality of metrics is determined using a blue component intensity vector and an ambient light component intensity vector that was received at a same time as the corresponding blue component intensity vector;
for each metric:
in response to determining that the metric is less than zero setting a scalar value to a negative number; and
in response to determining that the metric is greater than zero setting the scalar value to a positive number;
iteratively adding each scalar to a given light component intensity vector; and

determining a blue light component intensity vector based on result of iteratively adding each scalar to the given light component intensity vector.

10. The apparatus of claim 9 , wherein the electronic control unit is operable to calculate, based on the first dataset, the second dataset, and the third dataset, the ambient light unit vector and the ambient light intensity value by:
retrieving the red light component intensity vector, the green light component intensity vector, and the blue light component intensity vector; and
determining the ambient light unit vector and the ambient light intensity value based on the red light component intensity vector, the green light component intensity vector, and the blue light component intensity vector.

11. A method comprising:
receiving ambient light measurements for a plurality of optical channels of an ambient light sensor, the ambient light measurements taken over a time interval;
retrieving, fr

Assignees

• Ams Int Ag

Inventors

• Archibald James
• Nelson Doug
• Cogan Timothy

Classifications

• G09G2360/16

  Calculation or use of calculated indices related to luminance levels in display data · CPC title

• G09G2360/145

  the light originating from the display screen · CPC title

• G09G2360/144

  the light being ambient light · CPC title

• G09G3/3208

  organic, e.g. using organic light-emitting diodes [OLED] · CPC title

• G01J1/4204 Primary

  with determination of ambient light (solar light G01J2001/4266) · CPC title