A real-time stereo vision system for distance measurement and underwater image restoration

Abstract

This paper presents the development of an embedded real-time system that performs distance measurement and restoration of underwater images, using stereo vision techniques. To achieve a high performance low-cost implementation, the overall system has been developed using a hardware/software codesign approach. Several hardware modules have been designed to implement the several pixel intensive tasks, such as background image storage, background subtraction, center of mass calculation, and image restoration. On the other hand, less intensive tasks, such as the estimation of the disparity and the distance tasks (performed just once for each image), are executed using an embedded soft processor (Altera Nios II). The developed platform employs a pair of identical CMOS cameras for the stereo vision system, a low-cost FPGA, and an small screen for visualization of the images. In this paper, we describe both the overall design of the system and the calibration procedure used to determine the stereo vision system parameters. The Altera Quartus II was used as a synthesis tool, which estimates that the system consumes 115.25 mW and achieves an output of 26.56 frames per second for images of $$800\times 480$$ pixels. The synthesis results and the measurement precision show that the developed system is suitable for real-time tasks.