Vehicle headlight control using imaging sensor

Claim 2

A vehicle headlamp control, comprising: an imaging sensor that senses light in spatially separated regions of a field of view forward of a vehicle; and a control circuit that is responsive to said imaging sensor in order to determine if individual regions of the field of view include light levels having a particular intensity level in order to identify light sources of interest and provide a control output to said vehicle that is a function of the identification of light sources of interest including sensing oncoming vehicle headlights using a particular sensitivity and sensing leading vehicle taillights using a sensitivity higher than said particular sensitivity.

Claim 3

The vehicle headlamp control in claim 1 including an exposure control which determines an accumulation period of time said imaging sensor senses light in order to determine a value of sensitivity.

Claim 4

The vehicle headlamp control in claim 2 wherein said exposure control defines at least two accumulation periods, one of said accumulation periods being a relatively short accumulation period for detecting oncoming vehicle headlights and another of said accumulation periods being a relatively long accumulation period for detecting leading vehicle taillights.

Claim 5

The vehicle headlamp control in claim 1 wherein said control circuit includes a digital processor which provides a digital value of the sensed light level of each region.

Claim 6

The vehicle headlamp control in claim 1 wherein said imaging sensor includes a photosensor array.

Claim 7

The vehicle headlamp control in claim 5 wherein said imaging sensor includes a spectral separation device for dividing said photosensors into sensors which are each responsive to a particular spectral region.

Claim 8

The vehicle headlamp control in claim 6 wherein said spectral separation device divides said photosensors into red, green, and blue sensors which sense light in either a red, a green, or a blue portion of the spectrum.

Claim 9

The vehicle headlamp control in claim 6 wherein said spectral separation device divides said photosensors into red and red compliment sensors which sense light in either a red portion of the spectrum or a portion of the spectrum that is outside said red portion of the spectrum.

Claim 10

The vehicle headlamp control in claim 1 wherein said imaging sensor includes an optical device.

Claim 11

The vehicle headlight control in claim 9 wherein said optical device produces a higher resolution along an axis of vehicle travel than a resolution off of said axis.

Claim 12

The vehicle headlamp control in claim 1 wherein said control circuit switches the vehicle headlights between high-beam and low-beam states.

Claim 13

The vehicle headlamp control in claim 1 wherein said control circuit controls the vehicle headlights along a continuously variable value.

Claim 14

A vehicle headlight control, comprising: a solid-state light sensor array made up of a plurality of sensors arranged in a matrix on at least one semiconductor substrate and a spectral separation device to apply particular spectral regions to particular ones of said sensors, wherein each of said sensors responds to light in a particular spectral region; an optical device for directing light onto said sensor array in a manner which preserves spatial separation of light sources forward of the vehicle; and a control circuit that is responsive to said plurality of sensors in order to determine if spatially adjacent one or ones of said sensors are sensing light of a particular spectral signature above a particular intensity level in order to identify light sources that are either oncoming headlights or leading taillights to thereby control the vehicle headlights wherein first particular ones of said sensors respond to light in a first spectral region and second particular ones of said sensors respond to light in a second spectral region different from said first spectral region and wherein said control circuit identifies light sources by comparing light levels sensed by said first sensors with light levels sensed by said second sensors.

Claim 15

A vehicle headlight control, comprising: a solid-state light sensor array made up of a plurality of sensors arranged in a matrix on at least one semiconductor substrate and a spectral separation device to apply particular spectral regions to particular ones of said sensors, wherein each of said sensors responds to light in a particular spectral region; an optical device for directing light onto said sensor array in a manner which preserves spatial separation of light sources forward of the vehicle; and a control circuit that is responsive to said plurality of sensors in order to determine if spatially adjacent one or ones of said sensors are sensing light of a particular spectral signature above a particular intensity level in order to identify light sources that are either oncoming headlights or leading taillights to thereby control the vehicle headlights wherein first particular ones of said sensors respond to light in a first spectral region and second particular ones of said sensors respond to light in a second spectral region different from said first spectral region and wherein said control circuit identifies light sources by comparing light levels sensed by said first sensors with light levels sensed by said second sensors.

Claim 16

The vehicle headlamp control in claim 13 wherein said control circuit selects a first light exposure period for at least a portion of said array in order to detect oncoming headlights and a second light exposure period for at least a portion of said array in order to detect leading taillights.

Claim 17

The vehicle headlamp control in claim 14 wherein the same portion of said array senses oncoming headlights and leading taillights and said first and second light exposure periods are sequentially varied.

Claim 18

The vehicle headlamp control in claim 14 wherein different portions of said array sense oncoming headlights and leading taillights and each of said portions has one of said light exposure periods.

Claim 19

The vehicle headlamp control in claim 14 wherein the length of said second light exposure is at least ten times the length of said first light exposure.

Claim 20

The vehicle headlamp control in claim 17 wherein the length of said second light exposure is at least approximately 40 times the length of said first light exposure.

Claim 21

The vehicle headlamp control in claim 13 wherein said optical device produces a higher resolution along an axis of vehicle travel than a resolution off of said axis.

Claim 22

The vehicle headlamp control in claim 19 wherein said optical device has a magnification that is greater centrally of its field of view than at the periphery of its field of view.

Claim 23

The vehicle headlamp control in claim 13 including an ambient light detector which enables said control circuit during low ambient light conditions.

Claim 24

The vehicle headlamp control in claim 21 wherein said ambient light detector includes a portion of said sensors that are time-filtered in order to sense long duration changes in sensed light levels.

Claim 25

The vehicle headlamp control in claim 22 wherein said portion of said sensors are positioned on said array to receive light from sources close to the earth's horizon.

Claim 26

The vehicle headlight control in claim 13 wherein particular ones of said sensors respond to red light in generally a red spectral region and particular ones of said sensors respond to non-red light in a spectral region other than said red spectral region.

Claim 27

The vehicle headlight control in claim 24 wherein said control circuit detects leading taillights by determining that at least one of said red light responsive sensors is sensing a light level that is greater than a particular multiple of light sensed by at least one adjacent non-red light responsive sensor and that light level is greater than a particular threshold.

Claim 28

The vehicle headlight control in claim 24 wherein said control circuit detects oncoming headlights by determining that at least one of said red light responsive sensors and at least one adjacent non-red light responsive sensors are both sensing light levels within a particular ratio of each other and greater than a particular threshold.

Claim 29

The vehicle headlight control in claim 13 wherein said control circuit determines if a particular light source has a particular spectral signature by comparing levels of light sensed by sensors which respond to light in a particular spectral region with levels of light sensed by sensors which respond to light in a different spectral region.

Claim 30

The vehicle headlight control in claim 13 wherein said control circuit determines if a particular light source has a particular spectral signature by comparing levels of light sensed by sensors which respond to light in a particular spectral region with a threshold.

Claim 31

The vehicle headlight control in claim 28 wherein said threshold is a function of the spatial location of the particular sensor in the array.

Claim 32

The vehicle headlight control in claim 29 wherein said threshold is higher for sensors sensing light off a central forward axis of the vehicle than for sensors sensing light along said axis.

Claim 33

The vehicle headlight control in claim 28 wherein said control circuit determines if a particular light source has a particular spectral signature by comparing levels of light sensed by sensors which respond to light in a particular spectral region with levels of light sensed by sensors which respond to light in a different spectral region.

Claim 34

The vehicle headlight control in claim 13 wherein said solid-state light sensor and said optical device are positioned in a housing behind the vehicle's windshield.

Claim 35

The vehicle headlight control in claim 32 wherein said housing is behind a portion of the vehicle's windshield swept by wipers.

Claim 36

The vehicle headlight control in claim 33 wherein said housing is mounted to a bracket supporting a rearview mirror.

Claim 37

The vehicle headlight control in claim 32 wherein said housing is an interior mirror housing.

Claim 40

The method in claim 36 wherein said comparing includes exposing at least a portion of said sensors for a first exposure period in order to identify spectral signatures of headlights and exposing at least a portion of said sensors for a second exposure period in order to identify spectra signatures of taillights.

Claim 41

The method in claim 36 further including reading individual light intensity levels of each of said sensors.

Claim 42

The method in claim 38 including digital processing of said individual light intensity levels.

Claim 43

The method in claim 39 including digital processing using custom digital circuitry.

Claim 44

The method in claim 36 wherein said non-linear mapping of the field of view forward of the vehicle onto said array causes light sources positioned centrally in said field of view to be detected at a lower intensity than light sources positioned at the periphery of the field of view.

Claim 45

The method in claim 36 wherein said mapping includes masking portions of the field of view forward of the vehicle.

Claim 46

The method in claim 36 wherein said comparing light levels includes comparing light levels with thresholds, said thresholds being different for particular ones of said sensors.

Claim 47

The method in claim 43 wherein said thresholds are greater off a central forward axis of the vehicle than on said axis.

Claim 50

The method in claim 45 wherein said different sensing resolution is optically produced.

Claim 51

The method in claim 45 wherein the sensing resolution along said axis is greater than off of said axis.

Claim 52

The method in claim 45 including providing an optic device which provides a non-uniform magnification of said field of view.

Claim 53

The method in claim 45 wherein said solid-state photosensor array has sensor sizes which are non-uniform in said matrix.

Claim 54

The method in claim 45 wherein said identifying light sources of interest includes determining if each sensor is sensing a light level above a threshold level.

Claim 55

The method in claim 50 wherein said threshold is non-uniform for said sensors.

Claim 56

The method in claim 51 wherein said threshold is lower for sensors sensing portions of said field of view along an axis of vehicle travel than for sensors sensing, a portion of said field of view off of said axis.

Claim 57

The method in claim 45 including restricting light received by each sensor to a particular spectral region so that each sensor responds to light having a particular spectral range.