The present invention is a method and an apparatus that can image objects immersed in optically opaque fluids using ultrasound in a confined space and in a harsh environment. If the fluid is not highly attenuating at frequencies above 1 MHz, where commercial ultrasound scanners are available, such scanners can be adapted for imaging in these fluids. In the case of highly attenuating fluids, such as drilling mud, then a low frequency collimated sound source is used.
STATEMENT REGARDING FEDERAL RIGHTS
 This invention was made with government support under Contract No. DE-AC52-06NA25396, awarded by the U.S. Department of Energy. The government has certain rights in the invention.