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US 7,724,301 B2Granted
Determination of mechanical shutter exposure time
AssigneeNokia Corporation
InventorJuha Alakarhu
Life of this patent
Estimating the term…
Abstract
The specification and drawings present a new method, apparatus and software product for determining a mechanical shutter exposure time (e.g., an actual closing time) with a rolling readout of an image (e.g., complimentary metal oxide semiconductor) sensor using a predetermined calibration area of the image sensor in digital cameras or in electronic devices with digital cameras.
Claims33
An apparatus, comprising:
- a mechanical shutter, configured to provide a predefined exposure of an image, said predefined exposure is defined by a global reset time and a closing time of the mechanical shutter;
- and
- an image sensor with a rolling shutter capability, responsive to said predefined exposure, configured to provide an image signal comprising a calibration image signal and an actual image signal by a rolling readout of said image, wherein the calibration image signal is provided by the rolling readout of a predetermined portion of the image using a predetermined calibration area of the image sensor during a time interval between times corresponding to minimum and maximum tolerance values of said predefined exposure for determining, using a predetermined criterion, said closing time of the mechanical shutter using said calibration image signal for compensating of the actual image signal, wherein said predetermined calibration area does not overlap with an area of the image sensor used for providing said actual image.
A method, comprising:
- providing a predefined exposure of an image using a mechanical shutter, said predefined exposure is defined by a global reset time and a closing time of the mechanical shutter;
- providing an image signal comprising a calibration image signal and an actual image signal by a rolling readout of said image in response to said predefined exposure using an image sensor with a rolling shutter capability, wherein the calibration image signal is provided by the rolling readout of a predetermined portion of the image using a predetermined calibration area of the image sensor during a time interval between times corresponding to minimum and maximum tolerance values of said predefined exposure for compensating of said actual image signal, wherein said predetermined calibration area does not overlap with an area of the image sensor used for providing said actual image;
- and
- determining said closing time of the mechanical shutter using said calibration image signal for said compensating.
1 more element
An electronic device, comprising:
- a mechanical shutter, configured to provide a predefined exposure of an image, said predefined exposure is defined by a global reset time and a closing time of the mechanical shutter;
- and
- an image sensor with a rolling shutter capability, responsive to said predefined exposure, configured to provide an image signal comprising calibration and actual image signals by a rolling readout of said image, wherein the calibration image signal is provided by the rolling readout of a predetermined portion of the image using a predetermined calibration area of the image sensor during a time interval between times corresponding to minimum and maximum tolerance values of said predefined exposure for determining, using a predetermined criterion, said closing time of the mechanical shutter using said calibration image signal for compensating of the actual image signal, wherein said predetermined calibration area does not overlap with an area of the image sensor used for providing said actual image.
An apparatus, comprising:
- means for exposing image, for providing a predefined exposure of an image, said predefined exposure is defined by a global reset time and a closing time of the means for exposing image;
- means for sensing, responsive to said predefined exposure, for providing an image signal comprising a calibration image signal and an actual image signal by a rolling readout of said image, wherein the calibration image signal is provided by the rolling readout of a predetermined portion of the image using a predetermined calibration area of the means for sensing during a time interval between times corresponding to minimum and maximum tolerance values of said predefined exposure for determining, using a predetermined criterion, said closing time of the means for exposing image using said calibration image signal for compensating of the actual image signal, wherein said predetermined calibration area does not overlap with an area of the image sensor used for providing said actual image.
A processing module, comprising:
- a calibration processing module, configured to provide, in response to an image signal, a mechanical shutter exposure signal indicative of the predefined exposure of an image by determining a closing time of a mechanical shutter, said predefined exposure being defined by a global reset time and said closing time of the mechanical shutter,
- wherein said mechanical shutter is configured to provide said predefined exposure,
- and wherein said image signal comprises a calibration image signal and an actual image signal and is generated by an image sensor with a rolling shutter capability using a rolling readout of said image and in response to said predefined exposure and wherein the calibration image signal is provided using the rolling readout of a predetermined portion of the image using a predetermined calibration area of the image sensor during a time interval between times corresponding to minimum and maximum tolerance values of said predefined exposure, wherein said predetermined calibration area does not overlap with an area of the image sensor used for providing said actual image.
Dependencies are inferred from the claim text.