Multiple operating modes to expand dynamic range

Patent metadata

Field	Value
Publication number	US-10757320-B2
Application number	US-201816199998-A
Country	US
Kind code	B2
Filing date	Nov 26, 2018
Priority date	Dec 28, 2017
Publication date	Aug 25, 2020
Grant date	Aug 25, 2020

Abstract

Example embodiments relate to multiple operating modes to expand dynamic range. An example embodiment includes a camera system. The camera system may include a first image sensor having a first dynamic range corresponding to a first range of luminance levels in a scene. The system may also include a second image sensor having a second dynamic range corresponding to a second range of luminance levels in the scene. The camera system may further include a processor coupled to the first image sensor and the second image sensor. The processor may be configured to execute instructions to identify objects of a first type in a first image of the scene captured by the first image sensor and identify objects of a second object type in a second image of the scene captured by the second image sensor.

First claim

What is claimed is:

1. A camera system, comprising:
a first image sensor having a first dynamic range corresponding to a first range of luminance levels in a scene;
a second image sensor having a second dynamic range corresponding to a second range of luminance levels in the scene, wherein the second image sensor receives light from the scene via a neutral-density filter, and wherein the second range of luminance levels includes luminance levels that are higher than the first range of luminance levels; and
a processor coupled to the first image sensor and the second image sensor, wherein the processor is configured to execute instructions to:
identify objects of a first object type in a first image of the scene captured by the first image sensor, wherein the first object type has an expected luminance within the first range of luminance levels; and
identify objects of a second object type in a second image of the scene captured by the second image sensor, wherein the second object type has an expected luminance within the second range of luminance levels.

2. The camera system of claim 1 ,
wherein the first image sensor has a variable exposure that is adjusted by a controller executing instructions based on illuminance, and
wherein the second image sensor has a fixed exposure.

3. The camera system of claim 2 , wherein adjusting the variable exposure based on luminance comprises adjusting an exposure duration, an aperture size, a gain level, or an ISO sensitivity of the first image sensor.

4. The camera system of claim 2 ,
wherein the variable exposure is adjusted by modifying a shutter speed or gain associated with a shutter on the first image sensor,
wherein the first object type comprises:
objects in motion relative to the camera system and having high velocities relative to the shutter speed; or
actively illuminated objects that are modulated at faster rates than the shutter speed, and

wherein the second object type comprises:
objects in motion relative to the camera system and having low velocities or comparable velocities relative to the shutter speed; or
actively illuminated objects that are modulated at similar or slower rates than the shutter speed.

5. The camera system of claim 1 , further comprising a third image sensor having a third dynamic range corresponding to a third range of luminance levels in the scene,
wherein the processor is coupled to the third image sensor,
wherein the third range of luminance levels includes at least one luminance level that is lower than the first range of luminance levels, and
wherein the processor is further configured to execute instructions to identify objects of a third object type in a third image of the scene captured by the third image sensor, wherein the third object type has an expected luminance within the third range of luminance levels.

6. The camera system of claim 5 , wherein the third image sensor has a variable exposure that is adjusted by a controller executing instructions based on illuminance.

7. The camera system of claim 6 , wherein adjusting the variable exposure based on luminance comprises adjusting an exposure duration, shutter speed, an aperture size, or an ISO sensitivity of the third image sensor.

8. The camera system of claim 1 , wherein the first image sensor and the second image sensor are non-overlapping sensor regions of a single image sensor.

9. The camera system of claim 1 , further comprising:
a third image sensor having the first dynamic range; and
a fourth image sensor having the second dynamic range,
wherein the fourth image sensor receives light from a separate perspective of the scene via an additional neutral-density filter,
wherein the processor is coupled to the third image sensor and the fourth image sensor, and
wherein the processor is further configured to execute instructions to:
identify objects of the first object type in a third image of the separate perspective of the scene captured by the third image sensor; and
identify objects of the second object type in a fourth image of the separate perspective of the scene captured by the fourth image sensor.

10. The camera system of claim 1 , further comprising:
a third image sensor having the first dynamic range; and
a fourth image sensor having the second dynamic range,
wherein the fourth image sensor receives light from a separate perspective of the scene via an additional neutral-density filter,
wherein the processor is coupled to the third image sensor and the fourth image sensor, and
wherein the processor is further configured to execute instructions to:
identify objects of a third object type in a third image of the separate perspective of the scene captured by the third image sensor, wherein the third object type has an expected luminance within the first range of luminance levels; and
identify objects of a fourth object type in a fourth image of the separate perspective of the scene captured by the fourth image sensor, wherein the fourth object type has an expected luminance within the second range of luminance levels.

11. The camera system of claim 10 ,
wherein the third image sensor has a variable exposure that is adjusted by a controller executing instructions based on luminance, and
wherein the fourth image sensor has a fixed exposure.

12. The camera system of claim 11 , wherein adjusting the variable exposure based on luminance comprises adjusting an exposure duration, an aperture size, or an ISO sensitivity of the third image sensor.

13. The camera system of claim 1 , wherein the processor is further configured to execute instructions to:
identify objects of the first object type in the second image of the scene; and
check for errors in the identified objects of the first object type by comparing the objects of the first object type identified in the first image of the scene and the objects of the first object type identified in the second image of the scene.

14. The camera system of claim 1 , further comprising:
a first lens optically coupled to the first image sensor and having a first focal length; and
a second lens optically coupled to the second image sensor and having a second focal length,
wherein the first focal length is different than the second focal length,
wherein, correspondingly, the first image of the scene and the second image of the scene are captured at different focal lengths,
wherein the processor is further configured to execute instructions to generate an image that simulates an image captured by a simulated image sensor having a simulated lens optically coupled thereto, and
wherein the simulated lens has a focal length between the first focal length and the second focal length.

15. The camera system of claim 1 , further comprising:
a first lens optically coupled to the first image sensor and having a first focal length; and
a second lens optically coupled to the second image sensor and having a second focal length,
wherein the first focal length is different than the second focal length,
wherein, correspondingly, the first image of the scene and the second image of the scene are captured at different focal lengths, and
wherein the processor is further configured to execute instructions to:
identify objects of the first object type in the second image of the scene; and
determine a distance of one or more objects of the first object type in the scene from the camera system based on:
the first focal length;
the second focal length;
a focus of the one or more objects in the first image of the scene; and
a focus of the one or more objects in the second image of the

Assignees

• Waymo Llc

Inventors

• Wendel Andreas
• Dittmer Jeremy
• Hermalyn Brendan
• Ingram Benjamin

Classifications

• H04N23/45 Primary

  for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images · CPC title

• H04N23/61 Primary

  based on recognised objects · CPC title

• H04N23/75

  by influencing optical camera components · CPC title

• H04N23/72

  Combination of two or more compensation controls · CPC title

• H04N23/745

  Detection of flicker frequency or suppression of flicker wherein the flicker is caused by illumination, e.g. due to fluorescent tube illumination or pulsed LED illumination · CPC title