[in Japanese]

View full abstract

It has been shown that the fixed pattern noise (FPN) at the dark state of AMI is not caused by fluctuations in FET gain and photodiode dark current, but is cused by that of FET threshold voltage on each pixel. The threshold voltage fluctuation for each pixel was measured within±12 mVpp.
The FPN caused by this fluctuations can be eliminated by a software subtraction to give a value of more than 18 dB. Light exposure adds another FPN, due to the sum of the aperture ratio fluctuations and stray capacitance. Visual FPN at high illumination levels, however, is quite small and acceptable for practical use.

View full abstract

A signal processing method has been studied for digital contour correction suitable to high quality pictures. Analysis of Gamma corrected luminance signals shows that the physical factors indispensable for high quality pictures are degraded using the current method. Emphasis processes, such as amplitude extension in undershoot waveforms which are adaptive processes restricted for use near contour areas, are developed to obtain high picture quality. In experiments using these processes, dark objects in bright luminance areas are reproduced more naturally than by the current method. On a subjective 7-grade estimation scale, a picture quality improvement of about 1 grade is obtained. This method is useful for achieving higher quality pictures in IDTV and EDTV receivers.

View full abstract

[in Japanese]

View full abstract