Patent ID: 8847813

Claim:
An unsynchronized computed tomography (CT) imaging system, comprising: at least one pair of matched, but independent, continuous wave (CW) transmitters and receivers configured to radiate CW transmissions in a plurality of vector paths through solid geologic material with strategic known transmission and reception points in tunnels, wells, surfaces and/or boreholes; a computer configured to calculate and display tomographic images constructed from individual path travel times and signal attenuation measurements logged from registered locations from the CW transmitters and receivers having different transmitter and receiver perspectives around said geologic material necessary for computed tomography; and a device configured to normalize said individual path travel time or signal attenuation measurements such that variations in operating conditions, equipment, and components, do not render as false image artifacts in tomographic computations and displays; wherein, each of the CW transmitters and receivers include independent unsynchronized crystal oscillators rated at 10-ppm or better frequency uncertainty to produce and to detect CW transmissions.