| 摘要 |
A CT scanner (10) includes a radiation source (12) mounted for rotation about a scan circle (14). A ring of radiation detectors (30) includes narrow detectors (30n) and wide detectors (30w). The narrow and wide detectors are separately sampled (42n, 42w) and operated on with different digital filters (50n, 50w). The wider detectors have a more limited frequency response (32) which typically includes an out of phase response portion (36); whereas, the output signal from the narrow detetector has a higher frequency response (34), i.e. better resolution. The filters (50n, 50w) are selected to yield optimum signal to noise ratio. When the data is merged (60), the resultant data has a modulation transfer function with response (62) which has a higher frequency component or improved resolution relative to response (70) that would be obtained from detectors of uniform width of the average of the narrow and detector widths.
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