System and method for estimating an ambient light condition using an image sensor
First Claim
1. A computer-implemented method of calculating an ambient light estimate using an image sensor in a camera of a device, the method comprising:
- obtaining a digital image using the image sensor operating in at least one of;
a light-sensor mode, a camera mode;
storing the digital image in a computer memory storage element;
obtaining an array of pixels from the digital image;
defining a matrix of grid elements, each grid element comprised of multiple adjacent pixels of the array of pixels;
generating a set of measurement values for the matrix of grid elements based on the pixels associated with a respective grid element;
calculating a mean intensity value using the set of measurement values;
defining a threshold based on a multiple of a standard deviation from the mean intensity value;
identifying a set of grid elements having a first measurement value that satisfies a brightness criteria defined at least in part by the threshold;
calculating a weighted measurement value using the identified set of grid elements; and
calculating the ambient light estimate based on the weighted measurement value and the first measurement value.
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Abstract
A system and method for calculating an ambient light estimate using an image sensor in a camera of a device. An array of pixels is obtained using the image sensor. A matrix of grid elements is defined. Each grid element is comprised of multiple adjacent pixels of the array of pixels. A first measurement value is generated for a grid element of the matrix of grid elements based on the pixels associated with a respective grid element. A set of grid elements are identified having a first measurement value that satisfies a brightness criteria. A weighted measurement value is calculated using the identified set of grid elements. The ambient light estimate is calculated based on the weighted measurement value and the first measurement value.
140 Citations
20 Claims
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1. A computer-implemented method of calculating an ambient light estimate using an image sensor in a camera of a device, the method comprising:
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obtaining a digital image using the image sensor operating in at least one of;
a light-sensor mode, a camera mode;storing the digital image in a computer memory storage element; obtaining an array of pixels from the digital image; defining a matrix of grid elements, each grid element comprised of multiple adjacent pixels of the array of pixels; generating a set of measurement values for the matrix of grid elements based on the pixels associated with a respective grid element; calculating a mean intensity value using the set of measurement values; defining a threshold based on a multiple of a standard deviation from the mean intensity value; identifying a set of grid elements having a first measurement value that satisfies a brightness criteria defined at least in part by the threshold; calculating a weighted measurement value using the identified set of grid elements; and calculating the ambient light estimate based on the weighted measurement value and the first measurement value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A portable electronic device configured to calculate an ambient light estimate using a digital image, the portable electronic device comprising:
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a digital camera comprising an image sensor formed from an array of sensor cells, the image sensor configured to operate in a light-sensor mode and a camera mode; a computer memory for storing a digital image produced by the image sensor in at least one of;
the light-sensor mode, the camera mode;a computer processor for executing computer-readable instructions; the instructions for; obtaining an array of pixels from the digital image; defining a matrix of grid elements, each grid element comprised of multiple adjacent pixels of the array of pixels; generating a set of measurement values for the matrix of grid elements based on the pixels associated with a respective grid element; calculating a mean intensity value using the set of measurement values; defining a threshold based on a multiple of a standard deviation from the mean intensity value; identifying a set of grid elements having a first measurement value that satisfies a brightness criteria based in part on the threshold; calculating a weighted measurement value using the identified set of grid elements; calculating the ambient light estimate based on the weighted measurement value and the first measurement value. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification