Artificial Intelligence and Machine Vision

In this blog, I will discuss how to calibrate a suite of sensors used in a L2 autonomous prototype vehicle. Note: - To ensure a dataset generated from a L2 autonomous prototype, calibrate all sensors on board per each trip. In our autonomous vehicle prototypes, we use 6 - Cameras - we use 6 cameras - cropped native resolution from 1600x900 to smaller images - are in native BGR format. - with auto-exposure with a maximum limit of 20 ms. - use Bayer8 format for 1 byte per pixelin encoding - 1/1.8" CMOS sensor for 12 Hz capture frequency. - positions:   - one front center camera   - one front side mirrow camera per side   - one rear center camera   - one rear door centered camera per side 5 - Long Range RADARs - we use 5 sensors of RADAR - @ 13Hz capture frequency at 77 Ghz - measures distance & velocity, independently, in one cycle - positions:   - one front bumper center radar   - one front side mirror radar per side   - one...

Project Clear Sky Note: - This technology was created by me to enhance driving or flying conditions in poor weather. - This project is open sourced under GPL v3. - For the closed source for a commercial product, please contact dparksports at gmail dot com - Copyright 2010

Why RANSAC? Because we want a model of good feature matches. - Inliers:   - Good matches - Outlier:   - Bad matches Interest points (500/image) (640x480) What other algorithms are available? - Exhaustive search   - for each featfure, compare all other feactures in other images - Hashing   - compute a short descriptor from each feature vector - Nearest neighbor techniques:   - k-trees and their variants Putative correspondences (268) (Best match,SSD Outliers (117) (t=1.25 pixel; 43 iterations) How about outlier rejection? - use SSD (patch1, patch2) > threshold - 1-NN: SSD of the closest matches How to handle too many outliers? RANSAC loop: Select four feature pairs (at random) Compute homography H (exact) Compute inliers where  SSD(pi’, H pi) < ε Keep largest set of inliers Re-compute least-squares H estimate on all of the inliers Final inliers (262)