1993 Fiscal Year Final Research Report Summary
Image Formation of Moisture and Temperature in a Living Body by Microwave Computed Tomography
| Project/Area Number |
04452297
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
農業機械
|
|---|
| Research Institution | KYOTO UNIVERSITY |
|---|
Principal Investigator |
KATO Koro Kyoto University, Agriculture, Associate Professor, 農学部, 助教授 (70026566)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TORII Kiyoshi Kyoto University, Agriculture, Instructor, 農学部, 講師 (40026563)
|
|---|
| Project Period (FY) |
1992 – 1993
|
| Keywords | Microwave CT / Temperature distribution / Mllti-frequency / Time domain gate / Inverse Fourier transform / Moisture distribution / Multipass / TDR |
|---|
| Research Abstract |
Image formation of temperature and moisture distribution in living body was studied using multi-frequency microwave transmission CT and TDR.
1. We constructed a simple CT system for agricultural products using a microwave network analyzer and a personal computer. To eliminate the effect of multipath propagation, the system measured the frequency response, converted the data to the time domain and set the time gate corresponding to the direct path between 2 antennas. The gated response was transformed back to the frequency domain, and direct path response was obtained. Measured data at any frequency (1GHz-3GHz) could be selected or combined for projection data.
2. As a result of the image reconstruction by similar same method of X ray CT, the images which included the temperature and structure informations were obtained. The temperature image at a each frequency was obtained from the experiment of thermo-phantom using a water bottle, but the structural image was much stronger than the temperature image in the case of vegetable having voids between cells.
3. We noticed that the temperature coefficients of attenuation constant of water differ largely with frequencies ; thus, the method of extracting the temperature distribution from the image subtraction between the images obtainedat different frequencies, was proposed and experimented with. It became clear that the influence of the phantom wall and that of vegetable structure decreased and the temperature image improved using this method. The image of the thermo-phantom was also obtainted from phase constants.
4. The measurement of moisture disribution in grain layrs using time-domain reflectometry (TDR) was attempted, and it became clear that the moisture distribution of the thick grain layrs in silo or big dryer can be measured by TDR.
|
