Innovations in optical geocharacterization

With exponential increases in digital camera resolution, the last 15 years have witnessed major advances in the use of image analysis in geotechnical engineering. This paper highlights the history of photography and image analysis. It includes a d atabase of 100 recent references describing the use of image analysis in four geotechnical areas: site characterization; earth mass characterization; particle characterization; motion and deformation. Also described are the authors' development of image analysis systems for particle size and shape characterization. They include the Translucent Segregation Table (TST), Sedimaging, the Vision Cone Penetrometer (VisCPT), Stereophotography and In-situ Particle Tracking. Future research will lead to the estimation of intrinsic soil properties based on detailed assessment of particle size and shape distributions from images of both non- contacting and three-dimensional assemblies of particles.