Brightening the Optical Flow through Posit Arithmetic

International Symposium on Quality Electronic Design (ISQED), pp. 463–468

Abstract

As new technologies are invented, their commercial viability needs to be carefully examined along with their technical merits and demerits. The positTMdata format, proposed as a drop-in replacement for IEEE 754TMfloat format, is one such invention that requires extensive theoretical and experimental study to identify products that can benefit from the advantages of posits for specific market segments. In this paper, we present an extensive empirical study of posit-based arithmetic vis-à-vis IEEE 754 compliant arithmetic for the optical flow estimation method called Lucas-Kanade (LuKa). First, we use SoftPosit and SoftFloat format emulators to perform an empirical error analysis of the LuKa method. Our study shows that the average error in LuKa with SoftPosit is an order of magnitude lower than LuKa with SoftFloat. We then present the integration of the hardware implementation of a posit adder and multiplier in a RISC-V open-source platform. We make several recommendations, along with the analysis of LuKa in the RISC-V context, for future generation platforms incorporating posit arithmetic units.

Authors 7

1. Vinay Saxena

   Robert Bosch (India)

   Affiliation as printed

   Bosch Research and Technology Centre-India, Bangalore

   Bosch Research and Technology Centre - India, Bangalore

2. Ankitha Reddy

   Robert Bosch (India)

   Affiliation as printed

   Bosch Research and Technology Centre-India, Bangalore

   Bosch Research and Technology Centre - India, Bangalore

3. Jonathan Neudorfer

   Robert Bosch (India)

   Affiliation as printed

   Bosch Research and Technology Centre-India, Bangalore

   Bosch Research and Technology Centre - India, Bangalore

4. John Leroy Gustafson

   National University of Singapore

   Affiliation as printed

   National University of Singapore, Singapore

   National University of Singapore , Singapore

5. Sangeeth Nambiar

   Robert Bosch (India)

   Affiliation as printed

   Bosch Research and Technology Centre-India, Bangalore

   Bosch Research and Technology Centre - India, Bangalore

6. Rainer Leupers Aachen Institute for Communication Technologies and Embedded Systems

   RWTH Aachen University

   Affiliation as printed

   Institute for Communication Technologies and Embedded Systems, RWTH Aachen University, Germany

   [Institute for Communication Technologies and Embedded Systems RWTH Aachen University, Germany]

7. Farhad Merchant Aachen Institute for Communication Technologies and Embedded Systems

   RWTH Aachen University

   Affiliation as printed

   Institute for Communication Technologies and Embedded Systems, RWTH Aachen University, Germany

   [Institute for Communication Technologies and Embedded Systems RWTH Aachen University, Germany]