[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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MS (magnetic-focus electrostatic-deflection) type camera tubes are susceptible to video noise with a specific frequency spectrum concentrated around several MHz. The multi-reflection of the return beam and the noise in the deflection pulse are found to generate the video noise. The generation mechanism and the properties of the video noise are investigated through theoretical analysis and experimental simulation. The noise is reduced only to a small extent by defocusing or absorbing return beams, whereas the application of a noise-free deflection pulse generated on an integration principle almost completely reduces the video noise. The major factor the SN ratio of the deflection pulse, is required to maintain a greater than 85 dB (peak to peak) range for suppressing the video noise to an acceptable practical level.

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In noise reduction systems utilizing only the interframe correlation of video signals, it is well known that a form of time lag phenomena is often seen on the trace of the moving portion in the picture.
The described method in this paper utilizes a two-dimensional correlation and the interframe correlation of the video signal simultaneously. In the realized system, the 8th order Hadamard transform is applied to the frame difference signal, obtaining a high-performance noise extraction circuit.
The noise reduction system employing this method proves itself to be an efficient system causing much smaller image degradations including the time lag phenomena. It additionally selectively extracts and reduces rather distinctive noises generated in video equipment.
Results of the computer simulation prove the 8th order Hadamard transform usage to be sufficient for practical applications. Additionally, this idea is realized with a moderate amount of hardwave.

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