State monitoring apparatus

Patent metadata

Field	Value
Publication number	US-9679209-B2
Application number	US-201314408397-A
Country	US
Kind code	B2
Filing date	Jul 22, 2013
Priority date	Jul 25, 2012
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

In an image pickup system, illumination light emitted by a light emission part is collected and reflected by an optical member and is distributed to a predetermined area. This light distribution to the predetermined area permits a constituent point farther away from the light emission part to receive illumination light having a greater intensity of light being equal to or greater than a predetermined reference value. The image pickup system thus distributing the illumination light enables the intensity of light incident on each pixel constituting an image pickup predetermined area to be equal to or greater than an intensity reference value while enabling the distribution of the intensity of light incident on each pixel constituting the image pickup predetermined area to be within a first reference range.

First claim

The invention claimed is:

1. A state monitoring apparatus mounted in a vehicle to monitor a state of an occupant who is a driver of the vehicle, comprising:
at least one light emission part that emits light to project illumination light having a wavelength including at least a near infrared wavelength to a predetermined area that is defined as an area where a face of the occupant being the driver of the vehicle is positioned in space in a compartment of the vehicle;
an image pickup part that generates a picture image by receiving light incident from the predetermined area with an image sensor having a plurality of pixels;
a state monitoring section that monitors a state of the occupant being the driver based on a result of processing the picture image generated by the image pickup part; and
an optical control part that controls light distribution
to cause an intensity of light incident on each pixel included in an image pickup predetermined area
to be equal to or greater than an intensity reference value that is predetermined as an intensity of light providing a picture image suitable for image processing by the state monitoring section and

to cause a distribution of the intensity of light incident on each pixel included in the image pickup predetermined area
to be within a predetermined first reference range,

the image pickup predetermined area
being at least a part of a light receptive surface of the image sensor in the image pickup part, and
corresponding to the predetermined area,

wherein:
the predetermined area includes a center presence area where a central axis of the face of the occupant being the driver is probably positioned, while
the image pickup predetermined area includes an area corresponding to the center presence area, in the light receptive surface; and
the optical control part controls the light distribution in the center presence area such that
(i) a distribution of the intensity of the illumination light along a perpendicular direction is to be uniform, whereas
(ii) a distribution of the intensity of the illumination light along a horizontal direction is
to be greater to arrive at an area closer to the center presence area, and
to be smaller to arrive at an area farther away from the center presence area.

2. The state monitoring apparatus according to claim 1 ,
wherein the optical control part controls the light distribution
to cause the illumination light having a greater intensity
to arrive at a point farther away from the light source of the light emission part among points in the face of the occupant that is possibly present in the predetermined area.

3. The state monitoring apparatus according to claim 1 ,
wherein the optical control part includes at least one optical element.

4. The state monitoring apparatus according to claim 1 ,
wherein the light emission part individually includes a floodlight projector that emits the illumination light, and
wherein the optical control part is a plurality of the floodlight projectors that are arranged
to cause the illumination light having a greater intensity
to arrive at a point farther away from a light source in the light emission part among points in the face of the occupant probably present in the predetermined area.

5. The state monitoring apparatus according to claim 1 ,
wherein:
the at least one light emission part includes a plurality of floodlight projectors that each emit the illumination light having high rectilinearity;
the plurality of the floodlight projectors function as the optical control part;
the plurality of the floodlight projectors are arranged to cause the illumination light having a greater intensity to arrive at a point farther away from a light source in the light emission part, the point being among points in the face of the occupant probably present in the predetermined area; and
the plurality of floodlight projectors are arranged more densely in the perpendicular direction than in the horizontal direction to cause the distribution of the intensity of the illumination light along the perpendicular direction to be uniform.

6. The state monitoring apparatus according to claim 1 , further comprising:
a position determination section that determines whether or not a position where the face of the occupant is present is within the predetermined area; and
a brightness correcting section that performs correction control
to increase, when a result of determination at the position determination section reveals that the position where the face of the occupant is present is out of the predetermined area, a brightness value of each pixel in an area in the picture image corresponding to the position where the face of the occupant is present is increased to provide a picture image after the correction control,

wherein the picture image after the correction control by the brightness correcting section is taken as the picture image generated by the image pickup part.

7. The state monitoring apparatus according to claim 6 ,
wherein the brightness correcting section performs the correction control when the picture image is generated by the image pickup part.

8. The state monitoring apparatus according to claim 6 ,
wherein the brightness correcting section performs the correction control against the picture image that was generated by the image pickup part.

9. The state monitoring apparatus according to claim 1 , further comprising:
a filter portion that is placed on a path of the illumination light from the light emission part to the predetermined area, the filter portion having a filter that lets through light having a wavelength including a near infrared wavelength; and
an incidence reduction part that reduces light incident on the image sensor through the filter portion.

10. The state monitoring apparatus according to claim 9 ,
wherein the incidence reduction part is an attenuating portion that is placed in the filter and attenuates the illumination light propagating in the filter.

11. The state monitoring apparatus according to claim 1 , wherein
the optical control part includes
an incident part that collects the illumination light projected by the light emission part, and
a projecting part that performs, at a projecting surface, light distribution that projects the illumination light collected by the incident part to the space in the compartment
to cause the intensity of light incident on each pixel included in the image pickup predetermination area,

wherein the optical control part is an optical member including the projecting part that is connected to a connecting face that is a plane formed in the incident part.

12. A state monitoring apparatus mounted in a vehicle to monitor a state of an occupant who is a driver of the vehicle, comprising:
at least one light emission part that emits light to project illumination light having a wavelength including at least a near infrared wavelength to a predetermined area that is defined as an area where a face of the occupant being the driver of the vehicle is positioned in space in a compartment of the vehicle;
an image pickup part that generates a picture image by receiving light incident from the predetermined area with an image sensor having a plurality of pixels;
a state monitoring section that monitors a state of the occupant being the driver based on a result of processing the picture image generated by the image pickup part; and
an optical control part that includes
an incident part that collects the illumination light projected by the light emission part, and
a projecting part that performs, at a projecting surface, light distribution that projects the illu

Assignees

• Denso Corp

Inventors

• Omi Takuhiro
• Yamamoto Takahiro

Classifications

• H04N23/50

  Constructional details · CPC title

• H04N23/74

  by influencing the scene brightness using illuminating means · CPC title

• H04N23/56

  provided with illuminating means · CPC title

• H04N23/61

  based on recognised objects · CPC title

• H04N23/611

  where the recognised objects include parts of the human body · CPC title