Latency measurement system and method

• US 9,188,644 B1
• Filed: 11/01/2012
• Issued: 11/17/2015
• Est. Priority Date: 09/25/2012
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Blanton, William Brendan, Allen, Robert Crenshaw, DuBois, Thomas Alfred
• Primary Examiner(s): Patel, Jay
• Assistant Examiner(s): Mikeska, Neil
• Application Number:
  US13/665,993
• Time in Patent Office: 1,111 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G01R 31/3181 Functional testing G01R31/3177 takes precedence
• CPC Class Codes: G01R 31/31937 Timing aspects, e.g. measuring propagation delay G01R31/3191 and G01R31/31922 take precedence; marginal testing G06F11/24
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 2380/12 Avionics applications
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: H04N 17/04 for receivers

Abstract

The present disclosure is directed to a system for, and method operating latency measurement including an event generation device that generates an initial event used to measure system latency. A component test system receives the event and in response outputs a test component output signal and a zero-latency indicator. An electronics system including a multifunction display unit receives the test component output signal and displays a visible element on the multifunction display unit. A camera generates a series of recorded images, where each recorded image contains an image of the zero-latency indicator and an image of the visible element. A processor then determines the system latency by determining a time difference in the series of recorded images between a representation of an occurrence of the event in the image of the zero-latency indicator and a representation of the occurrence of the event in the image of the visible element.

Claims

1. A latency measurement system, the system comprising:

an event generation device that generates an event used to measure system latency;

a component test system that receives the event and in response outputs a test component output signal and changes a state of a zero-latency indicator to produce a visual output representing receipt of the event;

a receiving system that receives the test component output signal and outputs a corresponding visible element;

a camera that generates a series of recorded images, where each recorded image contains an image of the zero-latency indicator and an image of the visible element; and

a processor that determines the system latency by determining a time difference in the series of recorded images between a representation of an occurrence of the change of state of the zero-latency indicator in the image and a representation of the occurrence of the event in the image of the visible element.

2. The latency measurement system of claim 1, wherein the generated event further comprises one of:

an event trigger signal;

rotational motion;

electromagnetic radiation;

or

continuous motion.

3. The latency measurement system of claim 1, wherein the component test system further comprises one of:

a combination of an imaging device and an electromagnetic radiation emitter;

a combination of an actuator that actuates a switch and an electromagnetic radiation emitter;

a combination of an inertial navigation system and an electromagnetic radiation emitter;

or

a combination of a continuous variable controller and an electromagnetic radiation emitter.

4. The latency measurement system of claim 1, zero-latency indicator comprises an electromagnetic radiation emitter, and wherein the change of state of the electromagnetic radiation emitter comprises one of the emitter beginning to emit electromagnetic radiation and the emitter ceasing to emit electromagnetic radiation.

5. The latency measurement system of claim 4, wherein the electromagnetic radiation emitter further comprises:

an infrared illumination source;

a low-level visible light illumination source;

a visible light source;

or

a laser output of a laser level.

6. The latency measurement system of claim 1, wherein the receiving system further comprises at least one of:

an avionics control system;

a vehicle control system;

or

a ship control system.

7. The latency measurement system of claim 1, further including a multi-function display for displaying the visible element, wherein the multi-function display device further comprises at least one of:

a graphical image display device that graphically displays images based input received at the receiving system;

a warning/caution/advisory (WCA) indicator display that is activated based input received at the receiving system;

or

an artificial horizon display that corresponds to input received at the receiving system.

8. The latency measurement system of claim 1, where determining the time difference further comprises:

detecting a threshold within the representation of the occurrence of the change of state of the zero-latency indicator in the image and a threshold within the representation of the occurrence of the event in the image of the visible element;

creating a plurality of binary waveforms based on detecting the threshold within the representation of the occurrence of the change of state of the zero-latency indicator in the image and the threshold within the representation of the occurrence of the event in the image of the visible element;

detecting edges for each of the plurality of binary waveforms that measure one of rising or falling; and

measuring a delta time between the zero-latency indicator and the image of the visible element based on the detected edges for each of the plurality of binary waveforms.

9. The latency measurement system of claim 1, wherein determining the time difference further comprises:

determining the difference in a rate of angular change between the representation of the occurrence of the change of state of the zero-latency indicator in the image and a rate of angular change of the representation of the occurrence of the event in the image of the visible element.

10. A method of measuring latency, the method comprising:

triggering an event that generates an indication of the event and changes a state of a zero-latency indicator at substantially the same time to produce a visual output representing receipt of the event;

recording a series of images with a camera, where each image contains both a representation of the zero-latency indicator and a representation of the indication of the event; and

processing, by a computing device, the series of images to compute a latency value based on determining a time difference between the indication of the event and the change of state of the zero-latency indicator.

11. The method of measuring latency according to claim 10, wherein the triggering an event further comprises one of:

generating an event trigger signal;

generating rotational motion;

or

transmitting electromagnetic radiation.

12. The method of measuring latency according to claim 10, further comprising:

wherein the change of state of the zero-latency indicator comprises emitting an electromagnetic radiation emission corresponding to the zero-latency indicator based on receiving the indication of the event.

13. The method of measuring latency according to claim 12, wherein the emitting the electromagnetic radiation emission further comprises one of:

emitting an infrared illumination source;

emitting a low-level visible light illumination source;

emitting a visible light source;

or

emitting a laser output of a laser level.

14. The method of measuring latency according to claim 10, further comprising:

sending the indication of the event from a test component to a multi-function display device, wherein the sending the indication of the event further comprises sending the indication through an electronics system to the multi-function display device.

15. The method of measuring latency according to claim 14, further comprising:

displaying a visible element on the multi-function display device based on receiving the indication of the event at the multi-function display device.

16. The method of measuring latency according to claim 15, wherein the displaying the visible element further comprises one of:

displaying the visible element on a graphical image display device that graphically outputs display images based input received at the electronics system;

displaying the visible element on a warning/caution/advisory (WCA) indicator that is activated based input received at the electronics system;

or

displaying the visible element on an artificial horizon display that corresponds to input received at the electronics system.

17. The method of measuring latency according to claim 10, wherein the processing the series of images further comprises:

detecting a threshold within the representation of the change of state of the zero-latency indicator and a threshold within the representation the indication of the event;

creating a plurality of binary waveforms based on detecting the threshold within the representation of the zero-latency indicator and a threshold within the representation of the indication of the event;

detecting edges for each of the plurality of binary waveforms that measure one of rising and falling; and

measuring a delta time between the zero-latency indicator and the representation of the indication of the event based on the detected edges for each of the plurality of binary waveforms.

18. The method of measuring latency according to claim 10, wherein determining the time difference further comprises:

determining the difference in a rate of angular change between the indication of the event and a rate of angular change of a representation of the zero-latency indicator.

19. A method for measuring latency in electronic equipment, comprising:

generating pulsed source signals at a sensor aperture and at a multi-functional display;

capturing a source illumination and multi-functional display illumination directly and through a sensor path using a high frame rate camera;

isolating a plurality of regions of interest for the source illumination and the multi-functional display illumination in video captured by the high frame rate camera;

detecting peak thresholds in the regions of interest;

creating a plurality of binary waveforms based on the detected peak thresholds;

detecting a plurality of edges of the binary waveform measuring one of rising or falling; and

measuring a delta time between the source and the multi-functional display edges providing a latency measurement.

20. The method of claim 19, further comprising:

generating the source illumination by emitting an electromagnetic radiation emission based on receiving the generated pulsed source signals; and

generating the multi-functional display illumination by receiving an event signal based on the generated pulsed source signals.