"developing real-time video applications with coaxpress," a presentation from euresys

Copyright © 2017 Euresys 1

Jean-Michel Wintgens

May 2017

Developing Real-time Video

Applications with CoaXPress


Introducing Euresys


• Manufacturer of frame-grabbers and image processing software libraries

• Since 1989

• Staff: 45 people

• Head office in Belgium

• Sales offices in California, Singapore, China and Japan

• Specialize in image capture and camera control for machine vision and

computer vision applications

• Selling 25 K frame grabbers and 10 K software licenses per year

• Member of the AIA, EMVA, JIIA and the Embedded Vision Alliance

• Active member of the CoaXPress technical committee

Introducing Euresys


What is CoaXPress?


• A video transport standard for Computer Vision

• Camera – Frame Grabber Interface

• High data rate

• Up to 6.25 Gbps (8b/10b encoded: 625 MByte/s) over a single

coaxial cable

• Link aggregation: 8-connection cameras at 50 Gbps (5 GByte/s) are

available off-the-shelf

• 12.5 Gbps per connection under development

• Acquire images from the fastest and highest-resolution cameras

What is CoaXPress?


• Flexible and reliable cable

• Use standard coaxial cables

• Ease of integration

• Simplify cabling and reduce costs with a single coaxial cable for

• Data transfer

• Camera control

• Power

• Take advantage of robust connectors

• With a push/pull latching system for reliability in industrial applications

CoaXPress Benefits


• Standard 75-Ohm Coaxial Cable

• Asymmetric High Speed Serial Communication

• Connection Aggregation

• Use multiple cables to increase performance

• 1, 2, 4, or more

CoaXPress

Image /Video

Control +Trigger

Power over CoaXPress


• Comparison with other interfaces

Bandwidth

Interface Bandwidth

GigE Vision/Ethernet 230 Mbyte/s

USB3 400 Mbyte/s

Camera Link 850 Mbyte/s

(1 x CXP-6)625 Mbyte/s

(8 x CXP-6)5000 Mbyte/s


• Comparison with other interfaces

Cable length

Interface Cable length

GigE Vision/Ethernet 100 m / 330 ft

USB3 3~5 m / 10~16 ft

Camera Link 6~10 m / 20~32 ft

(CXP-1)130 m / 430 ft

(CXP-6)40~80 m / 130~260 ft

(CXP-12)20~40 m / 65~130 ft


• Adopted by Major Camera Manufacturers

CoaXPress Benefits


• Problem

• Trigger is asynchronous with any other traffic on the CoaXPress link

• Frame grabber sends the trigger packet (6 characters) to the camera

using 20.83 Mbps uplink

• Traffic is 8b/10b encoded

• Packet insertion at character boundary, one 10-bit character is 480 ns

• Potential jitter up to 7 x 480 ns = 3.4 µs

CXP Fixed-latency low-jitter camera triggering


CXP Fixed-latency low-jitter camera triggering

• Solution

• Measure the time between

trigger event and sending trigger

packet (time unit = 2 ns)

• Send the delay in the packet

• The camera waits (480 ns - )

before issuing the trigger

• Fixed latency: 7 symbols: 3.4 µs

• Jitter: < 4 ns


Camera Trigger

Up Connection

(No Additional Cable)

Up Connection

(Additional CXP-6 Cable)

Bit Rate 20.833 Mbps 6.125 Gbps

Latency 3.4 µs 20 ns

Jitter +/- 4 ns +/- 1.6 ns

Trigger Rate Up to 125 kHz

Up to 250 kHz*

Up to 2 MHz

* Single message trigger mode


Euresys CoaXPress Frame Grabbers


• Coaxlink: general purpose CoaXPress frame grabbers

• Up to four CoaXPress CXP-6 connections

• PCIe 3.0 (Gen 3) or PCIe 2.0 (Gen 2) x4 bus

• Feature-rich set of up to 20 digital I/O lines

• Extensive camera control functions

• Memento event logging tool

Euresys CoaXPress Frame Grabbers


Euresys Coaxlink Series

CoaXPress Configuration and camera bandwidth

CXP-6 DIN-1

1 x 6.25 Gb/s

= 625 MB/s

CXP-6 DIN-2

2 x 6.25 Gb/s

= 1,250 MB/s

CXP-6 DIN-4

4 x 6.25 Gb/s

= 2,500 MB/s

PCIe

Bus

PCIe 2.0 (Gen 2) x4

1,700 MB/s (sustained

bandwidth)

Coaxlink Mono

Coaxlink Duo

Coaxlink Duo

PCIe/104

Coaxlink Quad

PCIe 3.0 (Gen 3) x4

3,350 MB/s (sustained

bandwidth)

- -

Coaxlink Quad G3

Coaxlink Quad G3 DF


• Two-connection ruggedized

CoaXPress frame grabber

• Ruggedized board for

industrial and transportation

embedded applications

• Small stackable PCIe/104

form factor

Coaxlink Duo PCIe/104-EMB


• Two-connection ruggedized CoaXPress frame grabber

• Extended temperature range: -40 to +85°C / -40 to +185°F

• Sustained shock: 40 g/11 ms (all axes – half-sine and saw tooth)

• Optional conformal coating

• Two CoaXPress CXP-6 connections: 1,250 MB/s camera bandwidth

• PCIe 2.0 (Gen 2) x4 bus: 1,700 MB/s delivery bandwidth

Coaxlink Duo PCIe/104-EMB


• Feature-rich set of IO

• High-speed differential inputs: Quadrature motion encoder

support up to 5 MHz

• Isolated current-sense inputs: 5 V, 12 V, 24 V signaling

voltages accepted, up to 50 kHz, individual galvanic isolation

up to 500 VAC RMS

• Isolated contact outputs

• High-speed 5V-compliant TTL inputs/LVTTL outputs

Coaxlink General Purpose IO


• C2C-Link is able to synchronize cameras connected

• To the same Coaxlink card

• To different cards in the same PC

• To different cards in different PCs

• Distributes camera trigger at up to 2.5 MHz

Coaxlink C2C-Link


• Memento event logging system

• Memento records an accurate log of events related to the camera,

the frame grabber and its driver as well as the host application

• It provides assistance during application development and

debugging, as well as during operation

Coaxlink Memento


• Memento event logging system

• It provides a precise timeline of

time-stamped events, with

context information

• It is non-intrusive and works

with all Coaxlink cards

in the PC

Coaxlink Memento


• AMD DirectGMA

• Direct transfer of image data from Coaxlink to GPU memory

• Compatible with the AMD FirePro W5x00 and above

and all AMD FirePro-S series products

• Sample program available

• NVIDIA GPUDirect for Video/Cuda

• Significant performance improvements

in data transfer times for applications

Coaxlink Image transfer to GPU


• Windows and Linux drivers

• x86 and x86_64 architectures

• AArch64 64-bit ARM architecture for Linux

• User-level API

• Dynamic libraries to use with ISO-compliant C/C++ compilers

• .NET assemblies to use with .NET framework 2.0 and above

Drivers


Applications


• For applications where

• Use of coaxial cable is prevalent

• Longer cable length is required

• Defense applications

• Security applications

• Medical applications

Applications


• For applications requiring

• High data rates

• High frame rates

• Long cable lengths, greater

cable reliability and flexibility

• Flat panel display inspection

• Solar glass inspection

• Glass inspection

Applications


• For applications requiring

• High resolution & frame rate

• Synchronized operation of

multiple cameras

• Complex lighting control

Strobed, IR, Multi-spectral…

• Consistent real-time timing

• Automated Optical Inspection

• Printing inspection

Applications


Applications


• Accurate synchronization between frame grabber and OS time

• Challenge

• Different start time

• Clock drift

• Low frequency drift variations

• Temperature

• CPU load

• Power supplies

Accurate Time Synchronization

OS Time

FG T

ime


• Solution

• Synchronization model

• Taking into account the drift

between clocks

• Robust against low frequency

drift variations

• Monitor the synchronization error

and react if it varies

• In practice

• Error < 2 µs (with clock precision 1 µs)

Accurate Time Synchronization

OS Time

FG T

ime


Summary


• A powerful standard for computer vision

• Simple and cost-effective

• 75 Ohm coaxial cable with industrial connectors

• Highly Integrated

• Data, control, real-time trigger, and power in the same cable

• Adopted by major camera manufacturers

• Highest rates

• 8 x CPX-6 50 Gbps 5 Giga Pixels/s

Summary


• A Powerful standard for computer vision

• Longest cables

• 130 m with CXP-1

• 40-80 m with CXP-6

• Reliable

• Resilient protocol

• A progressing standard

• Towards Higher Rates: CXP-12…

Summary


• Coaxlink: general purpose frame grabbers

• Up to four CoaXPress CXP-6 connections

• Choice of PCIe 3.0 (Gen 3) or PCIe 2.0 (Gen 2) x4 bus

• Feature-rich set of up to 20 digital I/O lines

• Extensive camera control functions

• Memento Event Logging Tool

Summary


Thank you for your attention!


CoaXPress Details


CoaXPress – Comparison with other interfaces

Interface Bandwidth Frame rate

4MP camera

Cable

length

Trigger

jitter

GigE Vision 1.0 Gbps 25 fps 100 m

USB3 5.0 Gbps 90 fps 3 ~ 7 m

Camera Link Base: 2.0 Gbps

80-bit: 6.8 Gbps

-

180 fps

6 ~ 10 m ☺

CXP-6

1x: 6.2 Gbps

2x: 12.5 Gbps

4x: 25.0 Gbps

142 fps

-

563 fps

40 m ☺


CoaXPress Down Link – Data Rates

Bit Rate (Gbps) Data Rate (MBps)

CXP-1 1.25 125

CXP-2 2.5 250

CXP-3 3.125 312

CXP-5 5 500

CXP-6 6.25 625

Pixel Rate

(Megapixel/s)1 x CXP-6 2 x CXP-6 4 x CXP-6

8-bit pixel 625 1,250 2,500

10-bit pixel 500 1,000 2,000

24-bit pixel 208 417 833


• 20.833 Mbps Communication Channel

• Control the Camera

• Setup the camera

• Control the camera operation

• Real-Time Triggering

• Trigger the camera exposure

• Control the exposure time

• Reliable protocol

• Fixed latency/Low jitter

CoaXPress Up Link


• 24 V DC

• 17 W provided by the frame grabber on each connector

• 4 W cable loss budget

• 13 W at camera side

• Connection Aggregation

• 2 Connections: 34 W (26 W)

• 4 Connections: 68 W (52 W)

• Plug and Play

• Automatic detection of PoCXP support

• Over-current protection

Power over CoaXPress (PoCXP)


Cable length

Cable

Type

Manufacturer

Reference

CXP-1 CXP-3 CXP-6

Industry

Standard

Belden 1694A 130 m 100 m 40 m

Gepco VSD2001 140 m 110 m 44 m

Canare L-5CFB 118 m 88 m 34 m

Flexible Belden 1505F 80 m 60 m 23 m

Gepco VHD2000M 81 m 61 m 24 m

Canare L-3CFB 72 m 60 m 24 m

Thinnest Belden 1855A 55 m 55 m 25 m

Gepco VDM230 66 m 62 m 25 m

Canare L-2.5CFB 43 m 43 m 20 m


• BNC Connector

• DIN 1.0/2.3 Connector

• Robust push/pull latching connection

system for reliable industrial applications

• Since CoaXPress 1.1

• Multi-Connector Assemblies

75-Ohm Connectors


• 8b/10b Encoding

• Increase the reliability of the transmission

• Detect data transmission errors

• Forward error correction is considered for a future CXP version

Data Transmission Reliability


• Resilient Protocol

• Data Packets (image and control)

• 32-bit CRC checksum

• Redundancy: Replication of critical packet header data

• Image & Synchronization Information

• Trigger Packets

• Using special K-codes in the 8b/10b coding

• Redundancy: Character replication

• Message Handshake: Acknowledge and resend procedure



• Connection Test Mode

• Standardized method to validate a system

• Mandatory for all CoaXPress Frame Grabbers and Cameras



• Comparison with Camera Link


InterfaceBit Stream

encoding

Resilient

Protocol

Connection

Test Mode

Camera Link No encoding No checksum No

8b/10b

32-bit CRC,

redundancy,

message

handshake

Mandatory

"developing real-time video applications with coaxpress," a presentation from euresys

Technology