Geiger-mode LiDAR Sensing Technology6 Geiger-Mode Sensing Technology 6 Geiger-mode Sensing Technology Geiger-mode is sensitive to a single photon Number of photons Peak power 1,000,000

1Geiger-Mode Sensing Technology

1Geiger-mode Sensing Technology

• Frisbee players at 50 meters

• Green car (15% reflectance) at 150 meters

• Black motorcycle (3% refl.) at 250 meters

• 60 mph highway traffic, at 350 meters

Geiger-mode LiDAR Sensing Technology


Geiger-mode LiDAR –The Dawn of Digital Mapping

Peter Kostoulas, Sr. Applications Engineer



• Expertise in indium phosphide lasers and avalanche photodiodes (APDs)

• Pioneers in single-photon, Geiger-mode sensing technology

• Specialization in long-range 3D LiDAR imaging to < 3 cm resolution

• Staff of 50, with over half holding advanced technical degrees

• Customers are leaders in their respective industries around the globe

• Autonomous navigation

• Defense/targeting

• 3D mapping

• Quantum communications

• Satellite tracking and long free-space optical communications

Introduction to Princeton Lightwave



• What is Geiger-mode?

• Some aspects of Geiger-mode detection technology

• Imaging with Geiger-mode cameras

• Applications

• Mapping

• Disaster Management

• Resource Management

• Autonomous navigation, including driverless cars

• Conclusion

Contents



• Single event detection is often referred to

as Geiger-mode detection, a term derived

from X-rays

• A Geiger-mode detector (GmD) emits a

macroscopic current from the detection of

a single photon

• Used with a clock, a GmD is ideal for

detection and Time-of-Flight (TOF)

ranging applications

What is Geiger-mode (Gm) detection?

Laser

Detector Reflector

Time of flight 2T1



Geiger-mode is sensitive to a single photon

Number of

photonsPeak power

1,000,000

100,000

10,000

1,000

100

10

1

Geiger-

mode

Linear-

mode

< 500 photons are detectable only in Geiger-

mode

Photon

Detectivity

l = 1550 nm,

1 nsec pulse

128 mW

12.8 mW

1.28 mW

128 nW

12.8 nW

1.28 nW

128 pW

Single-photon, or

Geiger-mode, APDs

• Are 500 times more

sensitive than

Linear-mode APDs

• Respond digitally

when sensing

photon(s) • (Output current of L-M

APD is proportional to

# of photons)



Flash LiDAR: Linear-mode processes light classically

• LiDAR is based on relative reflectance: at a given distance, the higher the reflectance, the

more photons are returning from the target

• Reflectance, then, is the probability that a single photon reflects rather than is absorbed

by the target

• Linear-mode LiDAR uses individual flashes of quadrillions

of photons (1mJ equals 7.8x1015 photons per pulse at 1550

nm) to obtain reflections at repetition rates of 20-30 Hz

Photons traveling to

reflector from source

Percentage of photons

reflected back

33%

reflector

• Resultant image is from trillions of photons per flash returning from the target to the detector

67%

reflector



Flash LiDAR: Geiger-mode processes photons serially

• Geiger-mode uses high repetition rate (200 kHz) at low energy

(1 nJ = 7.8x109 photons at 1550 nm)

• An image is formed based on the percentage of flashes that register a detection

33%

Target

Reflectance

67%

Case

A

Case

B

• Geiger-mode obtains same relative intensity information

faster and more efficiently than linear-mode



Geiger-mode detects through obscurants

75 m 300 mGate opened Obscurant is 25% transmissive,

25% reflective, 50% absorptive

100% specularlyreflective

target

T = 0 ms, 0 photons

T = 0+ms, 16 photons

T = 0.25ms, 16 photons

T = 0.5-ms, 16 photons






target

T = 0.5+ms, 8 photons (4 reflected / 4 transmitted)

T = 1-ms, 8 photons (4 reflected / 4 transmitted)

T = 1+ms, 4 photonsObscurant detected







target

T = 2ms, 4 photons

T = 3ms, 4 photons

T = 3.5-ms, 4 photons







target

T = 3.5+ms, 2 photons (1 reflected / 1 transmitted)

T = 4-ms, 2 photons (1 reflected / 1 transmitted)

T = 4+ms, 1 photon (reflected) Target detected!



• Gm technology originally developed for imaging through canopy

Geiger-mode LiDAR sees through foliage

Tree canopy obscures ground Geiger-mode images vehicle under canopyImages courtesy of Harris Corp.



• For the same

brightness source,

Geiger-mode has a

500 x advantage for

(Field of View x

Distance)

• (Diode laser has

1/10th lower beam

quality than a fiber

laser)

27dB margin lets Geiger-mode image farther/wider

1

10

100

1,000

10,000

0.010 0.032 0.100 0.316 1.000 3.16 10.00 31.62 100.00

# o

f FP

A P

ixel

s

Distance (km)

# of FPA Pixels as a Function of Range and Light Source

Fiber Laser - Lm Diode Laser - Gm Fiber Laser - Gm

Fiber laser, in Linear-

mode, detects 1 point at 1

km range

50x enhancement500x enhancement

128 x 32 FPA



• Geiger-mode camera

equivalent to Linear-mode

camera

• 32 x 32 on 100 µm pitch

• 128 x 32 on 50 µm pitch

Geiger-mode Focal Plane Array

32 x 32 Photodetector Array

Focal Plane Array with PDA mounted on Readout

Integrated Circuit

GmD pixel (contact side)

128 x 32 FPA on ROIC6.4 x 1.6 mm2 PDA

3.2 x 3.2 mm2



High Accuracy, High Resolution Geiger-mode Cameras

Model ArrayTiming

(ps)

Accuracy

(cm)

Returns

per

second

Blind

Readout

time (µsec)

Framed Data Output

Kestrel 32 x 32 250 3.75 200 M 3

Falcon 128 x 32 500 7.5 400 M 7

Free Running Data Output

Merlin 32 x 32 300 4.5 800 M N/A

10 x 10 x 10 cm3

New!



Laser Rx with

CameraScanner

Position

(INS)

Sys. Control & Data

Acquisition ComputerOperator

Data Storage

LiDAR Functional Block Diagram

3D LiDAR Imaging with Laser and Gm Camera

Courtesy of

Harris Corp

Laser & camera

embedded in

scanner

~ 40 x 40 x 40 cm3



Geiger-mode maximizes resolution at long-range

Images courtesy of Harris Corp.

Linear-mode Geiger-mode

• From 8 km altitude, Geiger-mode provides ten times higher resolution

Details such

as power

lines and

shrubs now

visible

Significant

infrastructure detail

enhances disaster

response initiatives


LiDAR in Resource Management

Courtesy of Harris Corp

What Can Geiger-mode Deliver?

• High level of detail

– Resolution capability that

surpasses USGS QL1 (8 pts/m2)

– Rich point cloud

• Ability to image below canopies

• Lower cost of obtaining data

– Ability to scan more often,

which enables tracking

changes more frequently and

effectively

– Ability to manage larger areas

due to time and cost savings


LiDAR in Disaster Management

• Enhanced speed of collection

– Higher altitude operation allows more coverage in shorter time period

– Time is critical for disaster response

• Resolution capability that surpasses USGS QL1 (8 pts/m2)

– Provides detail information regarding power lines and other critical

infrastructure

– Enhanced ability to identify transportation link breakdowns for first

responders

• Lower cost of obtaining data

– Enables multiple passes for ‘before’ and ‘after’ or for situation updates

What Can Geiger-mode Deliver?

7 km aerial imaging at 20 pts/m2, McGuire Nuclear Station, N.C. Uses Falcon 128x32 Geiger-mode LiDAR Camera Courtesy of Harris Corporation. Ref: W. E. Clifton, B. Steele, G. Nelson, A. Truscott, M. Itzler, M.

Entwistle, “Medium Altitude Airborne Geiger-mode Mapping Lidar System” Proc. SPIE 9465, 946506 (May 2015).


• Power line detail visible from 7 km AGL

• Disaster relief needs to clearly identify:

– Missing or damaged utility wires

– Damaged roads

– Impacted infrastructure

• Geiger-mode achieves this

– Faster than linear

– More efficiently than other methods

Infrastructure Details Critical to Disaster Relief

7 km aerial imaging at 20 pts/m2, McGuire Nuclear Station, N.C. Uses Falcon 128x32 Geiger-mode LiDAR Camera Courtesy of Harris Corporation. Ref: W. E. Clifton, B. Steele, G. Nelson, A. Truscott, M. Itzler, M.

Entwistle, “Medium Altitude Airborne Geiger-mode Mapping Lidar System” Proc. SPIE 9465, 946506 (May 2015).


Geiger-mode for Autonomous Navigation



Geiger-mode camera used for autonomous flight

https://www.youtube.com/watch?v=udQ3WoK_Wdk&feature=youtu.be

• Sikorsky Blackhawk

navigates autonomously

using Falcon 128 x 32

Geiger-mode camera at

1550nm

Unmanned



ParameterGeigerCruizer™

Demo System

GeigerCruizer™

Long-Range

Image Format (Pixels) 512x64 512x128

Field of View (pixel) 2 mrad 2 mrad

Field of View (H x V), total 60° x 7.5° 60° x 15°

Raw Data Points/Image ~5 Million ~10 Million

Geiger-mode essential for high speed self-driving

• GeigerCruizer™ LiDAR images 300 meters, at 10% reflectance

• Real-time video refresh rates

• Enables use of eye-safe, scalable diode lasers

• Capability proven via GeigerCruizer™ Demo System

Demo System



• Fog highly

adverse to

imaging

• 80%

attenuation

• Backscatter

Geiger-mode images vehicle in dense fog

Noise Filtered in SoftwareUnfiltered

Dense fog

Shrubs Shrubs

• Software

filtering

– Resolves car and

shrubs

– Removes

backscatter and

other noise



GeigerCruizer™ Demo System



• Geiger-mode processes photons digitally and in real-time

• Resolution and imaging speed of Geiger-mode is unsurpassed

• 3D LiDAR applications being transformed

• Maps generated faster, at higher resolution

• More detailed images through obscurants: leaves, soot, rain,

fog, …

• High speed autonomous navigation & driving being enabled

• Geiger-mode extends imaging beyond traditional 3D LiDAR

Conclusion


THANK YOU!

GEIGER-MODE LIDAR –

THE DAWN OF DIGITAL MAPPING

www.princetonlightwave.com

[email protected]

http://www.princetonlightwave.com/


Geiger-mode Sensing Technology

Documents

Geiger-mode LiDAR Sensing Technology6 Geiger-Mode Sensing Technology 6 Geiger-mode Sensing Technology Geiger-mode is sensitive to a single photon Number of photons Peak power 1,000,000