Request-and-respond approach to reducing latency within a tracking system
First Claim
1. A method of tracking movement of an object comprising steps of:
- generating packets of tracking data indicative of positions of said object;
transferring a packet of said tracking data via a data link as a conditioned response to receiving a packet-transfer request;
receiving transferred packets of said tracking data at an output end of said data link;
processing said transferred packets such that said movement of said object is tracked by operations of said processing; and
triggering said packet-transfer requests in response to said processing such that said packets are transferred via said data link in accordance with processing requirements at said output end of said data link.
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Accused Products
Abstract
A method of managing latency in a system for tracking movement of an object includes providing a request-and-response mechanism for transferring tracking data across a communications link. In one embodiment, the object for which movement is to be tracked is a human head and the system is a virtual reality system. Packets of the tracking data may be generated using a conventional sensor processing technology, but the packets are transferred via the communications link to an image processing capability, such as that of a host computer. The packets are generated at a fixed sample rate that is asynchronous with respect to the processing requirements of the host computer. When the host computer is available for fresh tracking data, a packet-transfer request is transmitted to the source of the packet. Latency can be reduced by enabling the source of the packets to anticipate reception of a packet-transfer request. Thus, any incoming signal to the source is “prematurely” interpreted as a packet-transfer request. Appropriate actions are executed, if the interpretation is subsequently determined to be inaccurate. As a technique for reducing variability of latency, each transfer of a packet is preceded by a determination of whether to transmit a presently available packet or a next available packet. If a request is received momentarily before the next available packet is accessible, the presently available packet may be identified as “stale,” and the next packet may be transmitted when available.
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Citations
17 Claims
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1. A method of tracking movement of an object comprising steps of:
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generating packets of tracking data indicative of positions of said object;
transferring a packet of said tracking data via a data link as a conditioned response to receiving a packet-transfer request;
receiving transferred packets of said tracking data at an output end of said data link;
processing said transferred packets such that said movement of said object is tracked by operations of said processing; and
triggering said packet-transfer requests in response to said processing such that said packets are transferred via said data link in accordance with processing requirements at said output end of said data link. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of managing latency in a system for tracking movement of an object comprising steps of:
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forming signals of tracking data at a generally fixed processing rate, said tracking data being specific to said object, including forming said signals using tracking circuitry that is in communication with image processing circuitry via a data link, said image processing circuitry having an irregular processing rate with respect to requiring fresh tracking data;
at a first end of said data link common with said tracking circuitry, detecting when said image processing circuitry is available for processing fresh tracking data including receiving a request for fresh tracking data via said data link and anticipating receptions of said requests upon detecting incoming signals at said first end of said data link, said availability having an irregularity that is at least partially based upon said irregular processing rate of said image processing circuitry; and
in response to detecting that said image processing circuitry is available for processing fresh tracking data, transmitting tracking data to said image processing circuitry via said data link, said step of transmitting data being triggered by each anticipation of a reception of one of said requests. - View Dependent Claims (10, 11)
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12. A tracking system comprising:
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sensing means coupled to an object of interest for generating packets of tracking data indicative of positions of said object, said sensing means having a substantially fixed data generation rate;
signal processing circuitry for determining image information from said tracking data during a tracking operation; and
a data link connecting said sensing means to said signal processing circuitry, said signal processing circuitry being cooperatively configured with said sensing means such that said signal processing circuitry transmits requests to said sensing means for said packets during said tracking operation, said sensing means being responsive to said requests for said packets, said requests being transmitted according to processing requirements of said signal processing circuitry and being transmitted such that a data supply rate from said sensing means to said data link is less than said data generation rate. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification