CODED IMAGING SYSTEMS AND METHODS

摘要

1509685 Spatial filtering RAYTHEON CO 11 June 1975 [26 June 1974] 25082/75 Heading G2J [Also in Divisions H3-5] A coded imaging system (especially for nuclear imaging of living tissue) spatially codes the radiation from the object in accordance with a predetermined code and the code is altered synchronously with alterations in the spatial response of the image reconstructing means. The invention allows the use of an on-centre Fresnel pattern as the coding means thus suppressing the zero orders, as with the use of the known off-axis Fresnel pattern codes, but allowing higher intensity sources to be imaged (due to the greater spacing of the opaque rings of the pattern) or providing greater resolution at low intensities. In Fig. 1, nuclear radiation from the heart or lungs 11 is spatially coded by a rotating mask 12 comprising two complementary on-axis Fresnel zone patterns. A detector 14 spatially detects, amplifies and feeds the pattern to a data processor 16 which supplies signals to a CRT 18 which displays the signals as bright spots which are imaged via lens 20 through a mask 22 on to a film 24. Mask 22 comprises a bar pattern 66 which is reciprocated synchronously with the rotation of mask 12. The Film 24 is developed at 30, is evenly illuminated by 34 and the spots are re-imaged by lens 36 on to a second film 32 which is developed and bleached at 38. The bleaching leaves the film 32 transparent with variations in dielectric constant corresponding to spot positions. Hence the reconstructing light from laser 40 and pin hole 44 is deflected by the film 32 as a function of the information stored in the film and, after passing iris 54, forms an image of the object 11 on a ground glass screen 56. The mask 12 may have three zone patterns.