| 摘要 |
1,191,004. Pattern recognition. WESTERN ELECTRIC CO. Inc. 26 July, 1967 [29 July, 1966], No. 34307/67. Heading G4R. [Also in Divisions G1 and G2] A pattern is recognized using an array of mechanically-excitable optical fibres, a mask, an optical filter and photo-detector means. In Fig. 1, a speech (word) voltage waveform to be recognized is applied from source 19 to a quartz piezoelectric transducer 12 to set vibrating optical fibres 13 of various resonance frequencies. Coherent light from a source 11 passes down the fibres 13, through a mask 14 which blocks the light from stationary fibres 13, and lens 26 to a Fourier-transform holographic filter 16 which in response produces via a lens 27 a spot of light on a selected one of a matrix array of photo-detectors 17 to identify the word. The hologram 16 is produced by making a photograph of the light from the mask 14 when each of the possible words is applied to the transducer 12, arranging the photographs in a matrix array corresponding to the array of photodetectors 17 and forming a hologram photorecording of the Fourier transform of the array of photographs. In a modification, the photodetectors 17 are arranged in a circle around the optical axis OA, with lens 26 absent, the hologram 16 being produced by exposing a film to the light from the mask 14 while each of the possible words is applied to the transducer 12 in turn, the reference light used in thus forming the superimposed holograms coming from a different one of a plurality of mirrors in each case, the mirrors being arranged in a circle around the optical axis OA. The light is directed from the light source 11 to the selected mirror by a rotatable beam-splitter on the optical axis OA between the source 11 and transducer 12. In production of the hologram filter 16 in this case, a Fourier-transforming lens may be interposed between mask 14 and film, such lenses then being used also in the recognition apparatus. A vidicon may replace the array of photodetectors 17. |
