The optimum field viewing angle of the highest human judgement reliability for objects in virtual environment was investigated in this paper.

The field angle of fish eye lens can reached or exceed 180°, so the light path can of fish eye lens not be traced by an ordinary program.

With the example of Gran Taylor prisms, the authors deduced two types maximum field angles one of which is parrallel to the principal section, the other is vertical to it.

A simple method for calculating the field angle of a candy shape cold shield with the Monte Carlo method and MATLAB is presented.

Laser altimeter\'s field of view(FOV) is an important parameter affecting system\'s performance.

Comply with the constant principle of angle of view of sideway look bore hole TV system, the diameter of well is measured directly and simply by utilizing the television system, which is analyzed theoretically and at the same time has been proved through experiments.

With the help of the ray of equal rank and double-faced reflector,the telescopic visual angle of the spectrometer was analyzed and measured.

With the help of the ray of equal rank and double-faced reflector,the telescopic visual angle of the spectrometer has been analyzed and measured in the letterpress.