| Autor: |
H.S. Wise, R. Martin, E.W.T. Richards |
| Rok vydání: |
1969 |
| Předmět: |
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| DOI: |
10.1016/s0065-2539(08)61435-3 |
| Popis: |
Publisher Summary This chapter describes the digital read-out of an image intensifier using a Vidicon or a scanning spiral slit plus a digital memory oscilloscope. The instrument is a 1-m Czerny-Turner mounting specially designed to house the image intensifier. The slit is mounted vertically above the grating. The optics are set on a subframe made of nonmagnetic stainless steel, which is suspended in the main framework on vibration insulating mountings. The image intensifier and its permanent magnet are mounted on a stainless steel plate set at 45° to the optical axis. The content of each channel approaches exponentially the average value of the input signal to that channel with a superimposed random walk effect due to noise. The time constant of the system depends upon the signal-to-noise ratio and upon the weighting factor of the feedback loop. Scanning is repeated until sufficient frame-scans have been completed to give an acceptable signal-to-noise ratio. The scanning rate is approximately 12 frames/sec, so that to get an improvement in signal-to-noise ratio of 100:1, it is necessary to scan for 20 min. The spiral slit scanning system is also elaborated. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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