Comprehensive fixed pattern noise cancellation
First Claim
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1. A digital imaging method for use with an endoscope in ambient light deficient environments comprising:
- actuating an emitter to emit a plurality of pulses of electromagnetic radiation, wherein each pulse comprises an individual wavelength of electromagnetic radiation to cause illumination within the light deficient environment;
pulsing the emitter at a predetermined interval corresponding to a sensing interval of a pixel array;
sensing reflected electromagnetic radiation from a pulse with the pixel array to create an image frame in a plurality of cycles, the cycles including an integration time of the pixel array that is controlled using an electronic shutter, wherein a duration of the integration time is variable from cycle to cycle in the plurality of cycles between a readout of a first frame in a first cycle and a readout of a next subsequent frame in a second subsequent cycle and wherein the electromagnetic radiation pulse width and duration are variable during each cycle to adjust a level of light intensity caused by each pulse in the cycle, wherein variation of the integration time is related to the variation in the pulse width and the duration of the electromagnetic radiation pulse;
wherein the pixel array is actuated at the sensing interval that corresponds to the pulse interval of the emitter;
stopping the emitter from pulsing for a single iteration;
creating a dark frame by sensing the pixel array while the emitter is not pulsing a pulse of electromagnetic radiation;
creating one or more reference frames, based on pixel values in both the dark frame and in a plurality of previous dark frames, for use in removing fixed pattern noise;
removing fixed pattern noise from the image frame by subtracting stored reference data in the one or more reference frames from the image frame; and
creating a stream of images by combining a plurality of image frames to form a video stream.
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Abstract
The disclosure extends to methods, systems, and computer program products for producing an image in light deficient environments having cancelled fixed pattern noise.
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Citations
24 Claims
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1. A digital imaging method for use with an endoscope in ambient light deficient environments comprising:
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actuating an emitter to emit a plurality of pulses of electromagnetic radiation, wherein each pulse comprises an individual wavelength of electromagnetic radiation to cause illumination within the light deficient environment; pulsing the emitter at a predetermined interval corresponding to a sensing interval of a pixel array; sensing reflected electromagnetic radiation from a pulse with the pixel array to create an image frame in a plurality of cycles, the cycles including an integration time of the pixel array that is controlled using an electronic shutter, wherein a duration of the integration time is variable from cycle to cycle in the plurality of cycles between a readout of a first frame in a first cycle and a readout of a next subsequent frame in a second subsequent cycle and wherein the electromagnetic radiation pulse width and duration are variable during each cycle to adjust a level of light intensity caused by each pulse in the cycle, wherein variation of the integration time is related to the variation in the pulse width and the duration of the electromagnetic radiation pulse; wherein the pixel array is actuated at the sensing interval that corresponds to the pulse interval of the emitter; stopping the emitter from pulsing for a single iteration; creating a dark frame by sensing the pixel array while the emitter is not pulsing a pulse of electromagnetic radiation; creating one or more reference frames, based on pixel values in both the dark frame and in a plurality of previous dark frames, for use in removing fixed pattern noise; removing fixed pattern noise from the image frame by subtracting stored reference data in the one or more reference frames from the image frame; and creating a stream of images by combining a plurality of image frames to form a video stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A system for digital imaging system for use in ambient light deficient environments comprising:
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one or more processors; one or more memory devices operably coupled to the one or more processors and storing executable and operational data, the executable and operational data effective to cause the one or more processors to; actuate a laser emitter to emit a pulse of a wavelength of electromagnetic radiation to cause illumination within the light deficient environment; pulse the laser emitter at a predetermined interval corresponding to a sensing interval of a pixel array; sense reflected electromagnetic radiation from the pulse with the pixel array to create an image frame; wherein the pixel array is actuated in a plurality of cycles, that includes the pulse interval of the laser emitter, wherein the each cycle in the plurality of cycles includes an integration time of the pixel array that is controlled using an electronic shutter, wherein a duration of the integration time is variable from cycle to cycle in the plurality of cycles between a readout of a first frame in a first cycle and a readout of a next subsequent frame in a second subsequent cycle and wherein the electromagnetic radiation pulse width and duration are variable during each cycle to adjust a level of light intensity caused by each pulse in the cycle wherein variation of the integration time is related to the variation in the pulse width and the duration of the electromagnetic radiation pulse, stop the emitter from pulsing for a single iteration; sense the pixel array while the emitter is not pulsing a pulse to create a dark frame; create one or more reference frames, based on pixel values in both the dark frame and in a plurality of previous dark frames, for use in removing fixed pattern noise; remove fixed pattern noise from an image frame by subtracting values derived from one or more reference frames; and create a stream of images by combining a plurality of image frames to form a video stream. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification