| 摘要 |
<p>A system for increasing the depth of field and decreasing the wavelength sensitivity and the effects of misfocus-producing aberrations of the lens (25) of an incoherent optical system incorporates a special purpose optical mask (20) into the incoherent system. The mask, generally located at a principal plane or at the image of a principal plane, preferably modifies only the phase, and not the amplitude of light. The optical mask causes the optical transfer function to remain essentially constant within some range from the in-focus position. Signal processing (35) of the resulting intermediate image undoes the optical transfer modifying effects of the mask and results in an in-focus image over an increased depth of field. The mask may be used to increase the useful range of passive ranging systems.</p> |
