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.
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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