Methods and apparatus for a lighting-invariant image sensor for automated object detection and vision systems
First Claim
1. An active camera system configured to generate a lighting-invariant image of a scene comprising:
- at least one emitter configured to emit an active light pulse toward the scene;
an array of detectors configured to receive light for a field of view that includes at least a portion of the scene, each detector in the array of detectors configured to produce a linearized response to a number of incident photons of light;
control circuitry operably coupled to the at least one emitter and the array of detectors and configured to store at least two successive frames of data as frame pixels in one or more frame buffers, wherein each frame pixel is based on the linearized response from a corresponding one or more of the detectors in the array of detectors, wherein a duration of a capture cycle of the array of detectors is constant for the at least two successive frames but an intensity of the active light pulse emitted during each capture cycle is different for the at least two successive frames; and
a processing system operably coupled to the control circuitry and the one or more frame buffers to generate the lighting-invariant image of the scene, the processing system configured to;
analyze the at least two successive frames of data to determine a minimum intensity value due to ambient light in the scene and a maximum intensity value for frame pixels; and
generate the lighting-invariant image based on a difference between the minimum intensity values and the maximum intensity values of the frame pixels such that the image is based on a reflected portion of the frame data resulting from the active light pulse.
1 Assignment
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Accused Products
Abstract
An active camera system images successive frames of a scene utilizing an array of detectors configured to produce a response having a linear relationship to a number of incident photons. Multi-frame capture is utilized with differentiated frame illumination for successive frames. Frame processing allows the camera to produce, at the pixel level, different image intensities representing maximum signal intensity, ambient signal intensity, and object signal intensity. The linearized response of detectors in the lighting-invariant image sensor is used to establish non-attenuated signal strength that enables shadow removal and glare removal for one or more of the image signals. Embodiments of a lighting-invariant image sensor may be used in Autonomous and Semi-Autonomous Vehicle Control/Assist Systems.
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Citations
30 Claims
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1. An active camera system configured to generate a lighting-invariant image of a scene comprising:
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at least one emitter configured to emit an active light pulse toward the scene; an array of detectors configured to receive light for a field of view that includes at least a portion of the scene, each detector in the array of detectors configured to produce a linearized response to a number of incident photons of light; control circuitry operably coupled to the at least one emitter and the array of detectors and configured to store at least two successive frames of data as frame pixels in one or more frame buffers, wherein each frame pixel is based on the linearized response from a corresponding one or more of the detectors in the array of detectors, wherein a duration of a capture cycle of the array of detectors is constant for the at least two successive frames but an intensity of the active light pulse emitted during each capture cycle is different for the at least two successive frames; and a processing system operably coupled to the control circuitry and the one or more frame buffers to generate the lighting-invariant image of the scene, the processing system configured to; analyze the at least two successive frames of data to determine a minimum intensity value due to ambient light in the scene and a maximum intensity value for frame pixels; and generate the lighting-invariant image based on a difference between the minimum intensity values and the maximum intensity values of the frame pixels such that the image is based on a reflected portion of the frame data resulting from the active light pulse. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of generating a lighting-invariant image from two or more frames of image data of a scene, comprising:
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causing at least one emitter to generate and emit light within a defined frequency range throughout a field of view of the scene; causing an array of detectors to receive light within the defined frequency range for a field of view of the array of detectors, the field of view of the scene defined by the field of view of the array of detectors; controlling a start time and a duration of an image capture cycle of the array of detectors that correspond to a frame of image pixels that integrate image data of the scene, a start time of a pulse of emitted light from the emitter, and a relative difference in timing between the start time of the pulse of emitted light and the start time of the duration of the image capture cycle of the array of detectors; producing at least two successive frames of image pixels in which at least one of the relative difference in timing between the start times and the duration of the image capture cycle of the array of detectors is different; analyzing the frames of image pixels with a processing system to determine a minimum intensity value due to ambient light in the scene and a maximum intensity value of image pixels corresponding to a common point in the field of view of the scene; and generating the image based on the minimum intensity values and the maximum intensity values of the image pixels for the at least two successive frames of image data such that the image represents a reflected portion of the pulse of emitted light captured by the image pixels in that image. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. An active camera system attached to a vehicle and configured to generate lighting-invariant images of a scene that is in motion relative to the vehicle, the system comprising:
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at least one emitter configured to generate and emit light within a defined frequency range throughout a field of view of the scene; an array of detectors configured to receive light within the defined frequency range for a field of view of the array of detectors, the field of view of the scene defined by the field of view of the array of detectors; control circuitry operably coupled to the at least one emitter and the array of detectors and configured to; control a start time and a duration of an image capture cycle of the array of detectors that correspond to a frame of image pixels that integrate image data of the scene, a start time of a pulse of emitted light from the emitter, and a relative difference in timing between the start time of the pulse of emitted light and the start time of the duration of the image capture cycle of the array of detectors; produce at least two successive frames of image pixels of the scene in which at least one of the relative difference in timing and the duration of the image capture cycle of the array of detectors is different; a processing system operably coupled to the control circuitry to generate the images of the scene and configured to; analyze the at least two successive frames of image pixels to determine a minimum intensity value due to ambient light in the scene and a maximum intensity value of image pixels corresponding to a common point in the field of view of the scene; and generate each of the lighting-invariant images of the scene that is in-motion relative to the vehicle based on the minimum intensity values and the maximum intensity values of the image pixels for the at least two successive frames of image data. - View Dependent Claims (23, 24, 25, 26)
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27. An active camera system attached to a vehicle and configured to generate lighting-invariant images of a scene that is in motion relative to the vehicle, the system comprising:
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at least one emitter configured to emit active light within a defined frequency range throughout a field of view of the scene; an array of detectors configured to receive light within the defined frequency range for a field of view of the array of detectors, the field of view of the scene defined by the field of view of the array of detectors; control circuitry operably coupled to the at least one emitter and the array of detectors and configured to; control a start time and a duration of an image capture cycle of the array of detectors that correspond to a frame of image pixels that integrate image data of the scene; control the at least one emitter to emit active light during an entire period corresponding to the duration of the image capture cycle; produce at least two successive frames of image pixels of the scene in which there is a relative difference in the start time or the duration of the image capture cycle of the array of detectors; a processing system operably coupled to the control circuitry to generate the images of the scene and configured to; analyze the at least two successive frames of image pixels to determine a minimum intensity value due to ambient light in the scene and a maximum intensity value of image pixels corresponding to a common point in the field of view of the scene; and generate each of the lighting-invariant images of the scene that is in-motion relative to the vehicle based on the minimum intensity values and the maximum intensity values of the image pixels for the at least two successive frames of image data. - View Dependent Claims (28, 29, 30)
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Specification