This invention discloses methods and apparatus for ultrasonic color imaging that characterizes ultra-fine structures and distributional physical conditions within the target under inspection. The disclosed complementarily incorporates information arising from a plurality of repeated sound trips forced by repeated reflections of exterior and interior interfaces of target, and expresses the information into an image segment representing the main path that ultrasonic signals traveled within the target. The image produced is substantially more discriminative, descriptive, and position-sensitive to both acoustic interfaces and distributional acoustic characteristics of the target. The invention is especially useful for thin sheet targets most vulnerable to both non-continuous and continuous interior defects. The continuous interior conditions and effects of ultra-thin layered structures, that traditional ultrasonic inspection has been unable to express, are effectively expressed by linking their effects of deforming the waveform of passing ultrasonic signals to color image details.