| 摘要 |
PROBLEM TO BE SOLVED: To prevent lowering of capacity for direction analysis in a deeper place utilizing merits of the image softener method. SOLUTION: An adding machine ka of a load adding part 6 is to add the product of an RF signal Rb multiplied by the load coefficient αto an RF signal Ra to generate a composite RF signal Sa. And the adding machine ka of the load adding part 6 also adds the product of an RF signal Ra multiplied by the load coefficient α to the Rf signal Rb to generate a composite RF signal Sb. A load coefficient generation part 5 sets the load coefficient a at zero when the focal length is small, and at one when the focal length is large, and sets the load coefficient α between zero and one when the focal length is medium. Therefore, the opening is substantially wider in a deeper place, while the image softener method works in a shallower place. So high quality images can be obtained from shallower places through deeper places. |
