High-speed digital video serial link

• US 6,061,089 A
• Filed: 07/02/1999
• Issued: 05/09/2000
• Est. Priority Date: 03/24/1995
• Status: Expired due to Fees

• Current Assignee: Coastal Chromatics LLC (Intellectual Ventures LLC)
• Original Assignee: PPT Vision, Inc. (Datalogic S.p.A.)
• Inventors: Paulsen, Mark Thomas, Tonkin, Steven Wallace
• Primary Examiner(s): Garber, Wendy R.
• Assistant Examiner(s): MOE, AUNG SOE
• Application Number:
  US09/348,120
• Time in Patent Office: 312 Days
• Field of Search: 348/212, 348/211, 348/213, 348/218, 348/12, 348/15, 348/16, 348/17, 370/522, 370/465
• US Class Current: 348/211.6
• CPC Class Codes: H04N 21/23602 Multiplexing isochronously with the video sync, e.g. according to bit-parallel or bit-serial interface formats, as SDI
• CPC Class Codes: H04N 21/2381 Adapting the multiplex stream to a specific network, e.g. an Internet Protocol [IP] network transmission of MPEG streams over ATM H04L12/5601
• CPC Class Codes: H04N 21/4342 Demultiplexing isochronously with video sync, e.g. according to bit-parallel or bit-serial interface formats, as SDI
• CPC Class Codes: H04N 21/4363 Adapting the video stream to a specific local network, e.g. a Bluetooth® network
• CPC Class Codes: H04N 21/4381 Recovering the multiplex stream from a specific network, e.g. recovering MPEG packets from ATM cells transmission of MPEG streams over ATM H04L12/5601
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

Abstract

A system for bi-directional digital serial communication and control of remote units including video cameras and input/output devices in machine vision systems. The communication system includes a main processor, communication hubs and remote units. The system is capable of monitoring and controlling the remote units in real-time while receiving video data images from the remote video cameras. Digital signals are transmitted in two different protocols; one for data communications, and one for control communications.

Claims

1. A communications protocol for use on a high-speed machine-vision digital serial communications link comprising:

a packaged digital control packet having a first header that identifies the control packet as having control information and that provides routing information that identifies a source and a destination for the control packet on the digital serial communications link; and

a packaged digital video-data packet having a second header that identifies the video-data packet as having video data and that provides routing information that identifies a source and a destination for the control packet on the digital serial communications link;

wherein the first header and the second header are directly decodeable to distinguish control packets from video-data packets in order to provide high-speed operation for a machine-vision manufacturing operation, and

wherein the control packet is optionally inserted within the video-data packet such that the first header distinguishes the control pack from other information within the video-data packet without changing second header and without adding another header.

2. The communications protocol according to claim 1, wherein the control packet and the video-data packet each comprise a plurality of units of information, and the first and second header each include a designating bit that distinguishes a header unit of information from other units of information within the control packet and within the video-data packet.

3. The communications protocol according to claim 2, wherein each of the units of information passed on the digital serial communications link includes nine bits, the nine bits comprising the designating bit plus eight other bits.

4. The communications protocol according to claim 2, wherein the control packet and the video-data packet each further comprise an end-of-packet indicator, the end-of-packet indicator and the header both including the designating bit that distinguishes header and end-of-packet-indicator units of information from other units of information within the control packet and within the video-data packet.

5. The communications protocol according to claim 4, wherein each of the units of information passed on the digital serial communications link includes nine bits, the nine bits comprising the designating bit plus eight other bits.

6. A communications hub that uses the communications protocol according to claim 1, the communications hub comprising:

a processor interface connected to a main processor; and

a plurality of remote video camera interfaces connected to a plurality of remote video cameras, including a first remote video camera interface and a second remote video camera interface;

wherein the processor interface comprising;

a receiver that receives packaged digital transmissions from the main processor,

a first transmitter that transmits packaged serial digital signals to at least one of the plurality of remote video cameras on the first remote video camera interface,

a second transmitter that transmits packaged serial digital signals to at least one of the plurality of remote video cameras over the second remote video camera interface, and

a third transmitter that transmits packaged signals to the main processor over the processor interface;

wherein each one of the plurality of remote video camera interfaces comprises;

a receiver associated with each of the plurality of remote video cameras,

a controller associated with each receiver for controlling transmissions from one of the plurality of remote video cameras, and

a memory for storing the transmissions; and

wherein the communication hub is adapted to start a transmission of the video-data packet, and before completion thereof, insert the control packet within the transmission, and then complete the transmission of the video-data packet.

7. A machine vision control system for use in a manufacturing environment using two-directional high speed serial digital transmissions, the system comprising the communications hub according to claim 6, and further comprising:

the main processor coupled to the communications hub, and comprising;

a receiver that receives packaged digital signals including a header and either digital data and control signals,

a memory that stores the received digital signals,

a transmitter that transmits packaged serial digital signals, and

an analyzer circuit that analyzes received video image data and generates a content-analysis response based upon content of the video image data,

the plurality of remote cameras coupled to the communications hub and each having a communication hub interface for communication with the communication hub, the video camera comprising a transmitter, a receiver, and a controller for controlling communication with the communication hub;

wherein the communication hub distributes transmissions between the main processor and the plurality of remote video cameras.

8. The communications protocol according to claim 1, wherein the control packet and the video-data packet each further comprise an end-of-packet indicator, the end-of-packet indicator including a designating bit that distinguishes end-of-packet-indicators from other units of information in the respective packets.

9. The communications protocol according to claim 8, wherein each of the units of information passed on the digital serial communications link includes nine bits, the nine bits comprising the designating bit plus eight other bits.

10. A method of operating a machine vision control system having a plurality of remote video cameras including a first remote camera, and a main processor connected to the plurality of remote cameras by a digital serial link that includes a communication hub, the method comprising:

receiving an input trigger signal from a trigger source;

generating a digital control packet, including a first header, based upon the input trigger signal;

capturing an image of an object with the first remote video camera in response to the digital control packet;

converting the image to a digital video-data packet including a second header;

serially transmitting the digital video-data packet from the first remote video camera to the communication hub;

in the communications hub, evaluating a destination address identifier included in the second header, and transmitting the digital video-data packet to the main processor based on the evaluation; and

machine-vision analyzing the digital video-data packet with the main processor to evaluate the captured image and generating a response signal based on an image content of the captured image, wherein the first header and the second header are directly decodeable to distinguish control packets from video-data packets in order to provide high-speed operation for a machine-vision manufacturing operation.

11. The method according to claim 10, wherein the control packet and the video-data packet each further comprise a header unit of information and a plurality of other units of information, each unit of information including a designating bit that distinguishes a header unit of information from other units of information in the respective packets.

12. The method according to claim 11, wherein each of the units of information passed on the digital serial communications link includes nine bits, the nine bits comprising the designating bit plus eight other bits.

13. The method according to claim 10, wherein the control packet and the video-data packet each further comprise an end-of-packet indicator, the end-of-packet indicator including a designating bit that distinguishes end-of-packet-indicators from other units of information in the respective packets.

14. The method according to claim 13, wherein each of the units of information passed on the digital serial communications link includes nine bits, the nine bits comprising the designating bit plus eight other bits.

15. The method according to claim 10, further comprising

in the communications hub, inserting a control packet having a third header within the video-data packet such that the third header distinguishes the control packet with the third header from other information within the video-data packet without changing the second header and without adding another header.

16. A machine-vision control system for use in a manufacturing environment using two-directional high-speed serial digital transmissions comprising:

a main processor that receives digital video-data packets and digital control packets and that transmits digital control packets, the main processor including an analyzer circuit that analyzes received video image data and that generates and transmits a packaged digital control signal that includes a content-analysis response based upon content of the video image data;

a primary communication hub having a first interface and a plurality of second interfaces, the first interface connected to the main processor through a serial communication bus that transmits and receives the packaged digital data and control signals;

a plurality of remote video cameras each having a third interface that is connected to one of the plurality of second interfaces for two-directional communication with the primary communication hub; and

a first trigger source responsive to a manufacturing process or assembly step, that provides a signal commanding that one of the plurality of remote video cameras acquire an image;

wherein the digital video-data packets and digital control packets each have different headers that distinguish digital video-data packets from digital control packets, and the primary communication hub adapted to generate a priority response to a high priority request signal, the priority response being inserted between the beginning and end of transmission of a digital data packet carrying video information from one of the remote video cameras to the main processor, in order that high-speed automated manufacturing is performed.

17. The machine-vision control system according to claim 16, wherein the control packet and the video-data packet each further comprise a header unit of information and a plurality of other units of information, each unit of information including a designating bit that distinguishes a header unit of information from other units of information in the respective packets.

18. The machine-vision control system according to claim 17, wherein each of the units of information passed on the digital serial communications link includes nine bits, the nine bits comprising the designating bit plus eight other bits.

19. The machine-vision control system according to claim 16, wherein the control packet and the video-data packet each further comprise an end-of-packet indicator, the end-of-packet indicator including a designating bit that distinguishes end-of-packet-indicators from other units of information in the respective packets.

20. The machine-vision control system according to claim 19, wherein each of the units of information passed on the digital serial communications link includes nine bits, the nine bits comprising the designating bit plus eight other bits.