US 7,745,771 B2 · Synchronous imaging using segmented illumination

Abstract

In an actively illuminated imaging system, illumination of a segmented scene is synchronized with an image sensing period. A scene is segmented into a plurality of scene portions utilizing a segmented lens. In an aspect, a first scene portion is illuminated when an imager is actively collecting photogenerated charge from the first scene portion, and a second scene portion is illuminated when an imager is actively collecting photogenerated charge from the second scene portion. The sensitivity of an image sensor is maximized, while simultaneously minimizing the amount of light that must be supplied to illuminate a scene. An irradiance pattern is varied allowing a more uniform distribution of light. Bands of varying wavelength, polarization, and light intensity may be variously applied to illuminate individual scene segments, as needed to enhance an identification of an object in the scene. The present invention is particularly useful with high frame rate imaging systems.

Claims19

Dependent claims

A method of synchronizing an actively illuminated imaging system comprising:

employing one of a global shutter imager and a rolling shutter imager;
segmenting an image scene into a plurality of image scene portions comprising a first image scene portion and a second image scene portion;
sequentially illuminating the first image scene portion and the second image scene portion, wherein the first image scene portion is illuminated when an imager is actively collecting photogenerated charge as a function of light reflected from the first image scene portion, and the second image scene portion is illuminated when the imager is actively collecting photogenerated charge as a function of light reflected from the second image scene portion, wherein a time period of illuminating the first image scene portion is substantially equal to a time period of illuminating the second image scene portion;
and
sequentially reading out pixels of the imager to produce an image, such that the segmented image scene portions form the image.

2 more elements

An actively illuminated imaging system comprising:

a plurality of light sources for individually transmitting light;
and
a segmented lens for receiving the individually transmitted light, and directing the individually transmitted light to an image scene that is segmented into a plurality of image scene portions comprising:
a first image scene portion, wherein a first light source of the plurality of light sources transmits to a first segment of segmented lens to illuminate the first image scene portion;
and
a second image scene portion, wherein the first image scene portion and the second scene portion are sequentially illuminated, such that a second light source of the plurality of light sources transmits to a second segmented lens to illuminate the second image scene portion;
and
an imager configured to actively collect photogenerated charge as a function of light reflected from the first image scene portion when the first image scene portion is illuminated, and actively collect photogenerated charge as a function of light reflected from the second image scene portion when the second image scene portion is illuminated, such that the imager and the plurality of light sources are synchronized so that at least one of the plurality of image scene portions illuminated by at least one of the plurality of light sources is the portion that the imager is actively collecting photogenerated charge from, wherein a time period of illuminating the first image scene portion is substantially equal to a time period of illuminating the second image scene portion, and the imager is a rolling shutter imager, wherein pixels of the imager are sequentially read out to produce an image, such that the segmented image scene portions form the image.

5 more elements

Dependencies are inferred from the claim text.

Synchronous imaging using segmented illumination

Life of this patent

Synchronous imaging using segmented illumination

Life of this patent

Abstract

Claims19