Vehicle camera vision system and method
A vehicle vision system comprises first and second vehicle headlights configured to project first and second light structures into a travel path of the vehicle to illuminate an object in the travel path. The system includes a camera disposed in the vehicle between the first and second headlights to capture images of the object in response to capture signals. The first and second vehicle headlights alternately project the first and second light structures. A system controller synchronizes the capture signals so that images of the object captured by the camera include reflections of the first and second light structures. An image processor can reconstruct a surface geometry of the object based on the reflected first and second light structures.
1 . A system comprising:
a first headlight configured to project a first light structure into a travel path of a vehicle;
a second headlight configured to project a second light structure into the travel path of the vehicle;
a camera configured to capture an image of an object in the travel path;
a system controller communicatively coupled to the first and second headlights and the camera and configured to:
provide first control signals to first light emitting elements of the first headlight to define the first light structure,
provide second control signals to second light emitting elements of the second headlight to define the second light structure,
alternate projection of the first light structure by the first headlight with projection of the second light structure by the second headlight so that the first and second light structures are switched at a rate greater than about 50 Hz,
provide capture signals to the camera to trigger the camera to capture images of the object, and
synchronize the capture signals with the first and second control signals so that the projected first and second light structures are distinguishable in the captured images of the object.
2 . The vehicle vision system of claim 1 wherein the camera is between the first and second headlights so that the first light structure is projected from one side of the imager into the vehicle path of travel, and the second light structure is projected from the opposite side of the imager into the travel path of the vehicle.
3 . The vehicle vision system of claim 2 wherein the first light emitting elements comprise a first micro LED array and the second light emitting elements comprise a second micro LED array.
4 . The vehicle vision system of claim 3 wherein the controller is configured to provide first and second control signals to the first and second micro LED arrays respectively to select LEDs comprising even rows of the first micro LED array to emit light defining the first light structure, and to select LEDs comprising odd rows of the second micro LED array to emit light defining the second light structure.
5 . The vehicle vision system of claim 3 wherein the first control signals select LEDs of the first micro LED array to be switched from OFF to ON so that the first light structure is defined by vertical stripes of light and the second control signals select LEDS of the second micro LED array to be switched from OFF to ON so that the second light structure is defined by horizontal stripes of light.
6 . The vehicle vision system of claim 5 wherein the system processor is further configured to control the first and second LED arrays so that the first and second light structures are alternately projected and only one of the first and second light structures is projected at any given time.
7 . The vehicle vision system of claim 5 wherein the system processor is further configured to provide first and second control signals so that the first and second light structures are alternately projected at an alternation rate of about 50 Hz or higher.
8 . The vehicle vision system of claim 5 wherein the system processor is further configured to provide first row control signals to each row of light emitting elements comprising the first LED array; and to provide second row control signals to each row of light emitting elements comprising the second LED array, so that only even numbered rows of light emitting elements in both the first and second LED arrays emit light at a first instant and only odd numbered rows of light emitting elements in both the first and second LED arrays emit light at a second instant so that a projection of the first light structure at any given projection time comprises light from either the even numbered rows or the odd numbered rows but not both, and a projection of the second light structure at any given projection time comprises light from either the even numbered rows or the odd numbered rows but not both.
9 . The vehicle vision system of claim 1 wherein the light comprising the first and second light structures is light in the visible spectrum.
10 . A vehicle headlight system comprising:
a camera configured to respond to capture signals by capturing images of a scene in a travel path of the vehicle;
first and second headlights comprising respective first and second LED arrays;
first and second headlight optics arranged with respect to the first and second LED arrays to project first and second light structures respectively into the travel path to illuminate an object in the scene so that the captured images include images of the object in which the first and second light structures are reflected; and
a system controller configured to alternate projection of the first light structure by the first headlight with projection of the second light structure by the second headlight so that the first and second light structures are switched at a rate greater than about 50 Hz.
11 . The vehicle headlight system of claim 10 , wherein the system controller is further configured to provide first and second control signals to the first and second LED arrays respectively to select LEDs comprising even rows of the first LED array to emit light defining the first light structure, and to select LEDS comprising odd rows of the second LED array to emit light defining the second light structure.
12 . The vehicle headlamp system of claim 11 further including:
a delay table storing delay times for switching LEDs comprising the first and second arrays from an OFF state to an ON state;
first and second PWM controllers configured to:
provide width modulation (PWM) signals to respective corresponding groups of LEDs comprising the first and second arrays;
phase shift the PWM signals in accordance with the stored delay times so that not all LEDs to be switched from an OFF to an ON state are switched to the ON simultaneously.
13 . The vehicle headlight system of claim 10 , wherein the system controller is further configured to provide first and second capture signals to the camera and to synchronize the first and second capture signals with the first and second control signals so that the camera captures a first image of the object when the first headlight is projecting the first light structure, and captures a second image of the object when the second headlight is projecting the second light structure.
14 . The vehicle headlight system of claim 13 wherein the system controller includes a timer that synchronizes the first and second capture signals with the first and second control signals.
15 . A method comprising:
configuring a first vehicle headlight to project a first light structure into a travel path of a vehicle to illuminate a scene in the travel path;
configuring a second vehicle headlight to project a second light structure into a travel path of the vehicle to illuminate the scene;
disposing a camera in the vehicle between the first and second headlights so the camera can capture images of the scene;
controlling the first and second vehicle headlights to alternately project the first and second light structures into the travel path;
controlling the camera to capture at least one first image of an object in the scene while the first headlight is projecting the first light structure; and
controlling the camera to capture at least one second image of the object while the second headlight is projecting the second light structure.
16 . The method of claim 15 further including controlling the first and second headlights so that only one headlight at a time projects a light structure.
17 . The method of claim 16 further including controlling the first and second headlights so that the first headlight projects the first light structure for a time period less than about 20 ms, and the second headlight projects the second light structure for a time period less than about 20 ms.
18 . The method of claim 16 wherein the first headlight comprises a first LED array and the second headlight comprises a second LED array and the method further includes switching a plurality of LEDs comprising the first array from an OFF to an ON state to define the first light structure and controlling the switching such that not all of the plurality of LEDs defining the first light structure are switched ON simultaneously, and switching a plurality of LEDS comprising the second array from an OFF state to an ON state to define the second light structure and controlling the switching so that not all of the plurality of LEDs defining the second light structure are switched ON simultaneously.