Optical imaging tool is to provide detailed, oriented, structural and geological information. Applications: fracture detection and evaluation detection of thin beds bedding dip lithological characterization casing inspection true color rock fabric. The ALT 40mm Optical Borehole Televiewer or OBI40 is an advanced slimhole logging tool designed to optically image of the surface wall of open and cased wells, either in air or clear water. Designed to complement ALT Acoustic Televiewer (ABI40) in dry well situations