``Transparent Migration of Off-Line Frame Rate Vision Systems to Real-Time'' A. Tyrrell, J. LaPre, C. D. Carothers, B. Roysam and C. V. Stewart IEEE Transactions on Information Technology in Biomedicine, Volume 8, Number 2, June 2004.

ABSTRACT


This paper presents a collection of techniques and lessons learned in the context of efficient migration of a large and complex computer vision code base developed off-line into an equivalent real-time implementation under a standard open-source operation system (Linux). Using creative linking strategies, it is possible to create a robust environment based on loadable kernel modeuls that enables simultaneous realization of real-time and off-line frame rate computer vision systems from a single code based. Using our approach we demonstrate hard real-time predictability of a complex frame-rate vision system using commericial-off-the-self (COTS) hardware and a standard uni-processor Linux OS. This approach is simple; one can maximize systemic predictability by simply placing time-critical components of a user-level executable directly into the kernel as a virtual device driver. This effecitively emulates a single process space model that is non-preemptable, non-pageable and that has direct access to a powerful set of system level services. Experiments on a frame-rate vision system designed for computer-assisted laser retinal surgery shows that this kernel method reduces the variance of observed per frame CPU cycle counts by two orders of magnitude. The conclusion is that when predictable off-line algorithms are used, it is possible to efficiently migrate to a predictable frame-rate computer vision system.

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