Exposure ratio control
AssigneeApical Limited
InventorsMaxim Novikov, Alexey Kornienko, Alexis Leonardo Lluis Gomez
Life of this patent
Estimating the term…
Abstract
A method of determining an exposure ratio for use with a multi-exposure image capture system operable to capture a first image of a scene with a first exposure and a second image of the scene with a second exposure shorter than the first exposure. The exposure ratio is a ratio of the first exposure to the second exposure. The method comprises obtaining image data representative of an image captured using an image sensor of the image capture system and setting the exposure ratio in dependence on a distribution of counts relating to values of a characteristic of respective pixels of the image and a weighting function which varies with the values of the characteristic.
Claims20
A method of determining an exposure ratio for use with a multi-exposure image capture system operable to capture a first image of a scene with a first exposure and a second image of the scene with a second exposure shorter than the first exposure, the exposure ratio being a ratio of the first exposure to the second exposure, the method comprising:
- obtaining image data representative of an image captured using an image sensor of the image capture system;
- inputting distribution data derived from a distribution of counts relating to values of a characteristic of respective pixels of the image to an optimization function, each of a plurality of output values of the optimization function dependent on a respective one of a plurality of input exposure ratios input to the optimization function, wherein the optimization function is based on a weighting function which varies with the values of the characteristic;
- and
- setting the exposure ratio by selecting the exposure ratio from the plurality of input exposure ratios based on the plurality of output values of the optimization function.
An exposure controller for controlling an exposure ratio for use with a multi-exposure image capture system operable to capture a first image of a scene with a first exposure and a second image of the scene with a second exposure shorter than the first exposure, the exposure ratio being a ratio of the first exposure to the second exposure, the exposure controller operable to:
- obtain image data representative of an image captured using an image sensor of the image capture system;
- input distribution data derived from the distribution of counts relating to values of a characteristic of respective pixels of the image to an optimization function, an output value of the optimization function dependent on an input exposure ratio input to the optimization function, wherein the optimization function is based on a weighting function which varies with the values of the characteristic and the optimization function comprises a weighted signal to noise ratio (WSNR) function;
- and
- set the exposure ratio in dependence on the output value.
A method of determining an exposure ratio for use with a multi-exposure image capture system operable to capture a first image of a scene with a first exposure and a second image of the scene with a second exposure shorter than the first exposure, the exposure ratio being a ratio of the first exposure to the second exposure, the method comprising:
- obtaining image data representative of an image captured using an image sensor of the image capture system;
- and
- setting the exposure ratio in dependence on a distribution of counts relating to values of a characteristic of respective pixels of the image and a weighting function which varies with the values of the characteristic, wherein:
- the exposure ratio is a first exposure ratio;
- the multi-exposure image capture system is operable to capture a third image of a scene with a third exposure longer than the second exposure and shorter than the first exposure;
- and
- the method comprises setting a second exposure ratio of the third exposure to the second exposure in dependence on the first exposure ratio.
Dependencies are inferred from the claim text.