Methods and apparatus for a lighting-invariant image sensor for automated object detection and vision systems

A method of generating a lighting-invariant image from two or more frames of image data of a scene, comprising:

• 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.

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:

• 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.

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:

• 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.