Aberrations in holography appear when the geometry in reconstruction differs from that in the recording process. The diffraction patterns aberrated with third-order coma, astigmatism and their combination are easily obtained in holography. The experimental results are compared with numerical ones which are calculated by the Fourier-transforming of the pupil function and are displayed on CRT. There is fairly good agreement between experimental and numerical results. The influence of misalignment in the experimental arrangement is briefly evaluated. The relation between the sample number of pupil domain and the desired diffraction pattern is also considered.

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The method of pattern recognition by use of the optical matched filtering technique is studied. For simple patterns, usually, the auto-correlation pattern is significantly different from the cross-correlation pattern, but there is the case in which the auto-correlation is comparable in magnitude to the cross-correlation.
It is shown that the use of the correlation pattern can be useful for the discrimination of simple patterns such as Arabic numerals.

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Features of image formation in an optical system under partially coherent illumination are investigated for the case where the imaging process due to a nonlinear system can be assumed to be linear. It is shown that such condition is fulfilled in cases that (1) a small object in the bright background is imaged, (2) an object is imaged by an optical system illuminated with the light radiated from annular source with very narrow width and (3) a low amplitude and phase contrast object (Gabor-Zernike object) is imaged, in a microscope under partially coherent illumination. It is further shown through the evaluation of spatial frequency response in the linear system and observation of computer simulated images that a low phase contrast object becomes highly visible in coherent and near coherent illumination in an ordinary microscope in the presence of defocusing.

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Light intensity fluctuations at the image plane of a double-aperture imaging system are discussed in connection with the dynamic behaviour of an image speckle that is spatially modulated with Young's interference fringes. The dependence of fluctuations on the arrangement of the optical system is explained and confirmed by experiments. The criterion for both the velocity measurement using Doppler beat and the moire gauging technique proposed by Duffy is derived.

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A new digital data recording method which would be applied in large capacitive recording systems such as video file is proposed.
The recording medium used is consisted of two layers. A thermoplastic thin film is on a flat conductive plate, which is made of metal or nesa conductive film on a glass plate. Before data write-in, the thermoplastic film is given surface electrical charge. A focused laser beam is used as a write-in stylus. When the laser beam is irradiated on the thermoplastic film, the thermoplastic is melted. The surface of the melted thermoplastic is deformed into convex or concave shape by the electro-static force of the surface charge. The micro deformation of the thermoplastic is fixed when the melted plastic refreezes.
Experiments were done and the recorded spots were 1 micron diameter.
Recording characteristics are analyzed numerically. The given main results are that if light absorption of laser light in the thermoplastic is sufficient, the required power of laser is a several milli Watt for 10 Mbit/s bit rate recording.
Merits of this recording method are, (1) small required laser power, (2) real time recording, (3) erasability are rewrite-in ability, (4) low cost recording medium, (5) in the air operation.

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