On laser beam scanning systems including a spherical mirror having oblique angles to the incident beam, the distortions of f-θ linearity and spot size have been analysed, being compared with the characteristics of the parabolic mirror which were published in papers.
It is shown that the distortions could be minimized to nearly zero under the condition that the optical path length between the deflector and the mirror is set to an optimum value.
In the case of a spherical mirror, the optimum conditions are approximately 0.50f (f is the focal length) for the f-θ linearity and approximately 0.80f for the circle of confusion, somewhat varying with the direction of radius of the circle as well as the oblique angle and the deflecting angle.
The laser spot size has been obtained from the calculated circles of confusion, considering the Gaussian laser beam propagation property, and compared with the experimental result.

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An interferometric measuring method of aspheric surfaces, using the movement of test surfaces along the optical axis, is described. This method utilizes the following phenomenon: when a spherical wave incidents the aspheric test surface, intervals of the interference fringes spread extremely in the neighbourhood of the point where this spherical wave touches the test surface. Then, in this method, the positions of the test surface and the point where the fringe interval is the largest, are measured, and the shape of the test surface is estimated from these data by the simple recursive method. By this measuring method the aspheric surfaces, which depart large from the spheres, can be measured absolutely with interferometers which are available on the market.

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Simultaneous color contrast effect is understood as a visual phenomenon that chromatic responses are induced in the test field by the inducing stimulus. In order to provide an integrated account for the facts on this effect obtained by the previous authors, it seems fruitful to persue a quantification of the induced chromatic response. The usual methods of measurement have not permitted this quantification.
A method based on a hue-cancellation procedure is proposed for measuring the magnitude of the induced chromatic response. The experiment was carried out to confirm that this method can quantify the induced chromatic response independent of brightness contrast effect. The induced chromatic response functions, determined by using this method, could satisfactorily account for the facts on simultaneous color contrast effect obtained by the previous investigators.

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Chromatic inductions were determined as a function of wavelength of inducing stimulus by the method proposed in the previous paper, and also, compensatory shifts of spectral loci of unique hues for chromatic induction were measured.
The results showed that the chromatic induction could not be completely understood in terms of the opponent-color induction process by Jameson and Hurvich. The induced chromatic response functions obtained in this study, which could explain the facts on simultaneous color contrast effect found by the previous authors, could be fit fairly well with linear combinations of two classes of cone-receptor: the linear combination of R-cone and G-cone for the red-green function, and the linear combination of R-cone and B-cone for the yellow-blue function. This suggests that the simultaneous color contrast effect can be understood in the framework of the dual-opponent mechanisms.

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This letter describes a measurement of frequency response of photoelectric detectors by scanning the frequency of an optical beat, which is formed by the lights from two transverse Zeeman lasers. The frequency characteristic of a detector was obtained directly by the response of the detector to the optical beat because the optical outputs of the two Zeeman lasers are nearly constant for the cavity detuning.

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The most preferable color portraits are assumed to be photographs in which details of human skin are reproduced with low definition, while structures of other objects in the picture are imaged with high definition. Among three photosensitive layers of color films, green sensitive layer has the largest contribution for reproduction of blemishes in human skin by subjective evaluation of color portraits.
An optical phase-noise filter which diffuses only the green light is examined to realize low definition effects only in human skin for color portrait applications.
It is found that most suitable optical path difference given by thickness of phase portion is 2.5λG for our purpose of study from theoretical points of view. Effects of the filter are confirmed by experiments.

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A fθ lens system may be accomplished, incorporating a single plano-convex lens.

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