초록 ▼

A fixed-focus camera having a retractable close-up lens, fixed-focus lens, infrared filter, and optical low-pass filter disposed along an optical axis within a housing. The close-up lens is switchable between a close-up position coaxial with the optical axis and a far position not coaxial with the o

A fixed-focus camera having a retractable close-up lens, fixed-focus lens, infrared filter, and optical low-pass filter disposed along an optical axis within a housing. The close-up lens is switchable between a close-up position coaxial with the optical axis and a far position not coaxial with the optical axis. Light received from a target passes through an aperture in the housing and then through the lenses and filters. An image sensor receives the filtered light and outputs a two-dimensional array signal of corresponding voltages proportional to the energy of light striking each sensing element. The voltage signal from the image sensor is filtered using a high-pass filter and the high-frequency components of the signal are measured to determine a relative focal value for the light received from the target. The close-up lens is retracted for calculating a far-position focal value and then engaged for calculating a close-up position focal value, and the calculated focal values are compared to empirically-derived constant values to determine which lens position will produce a better-focused image.

대표청구항 ▼

A camera comprising: a close-up lens retractably disposed on an optical axis; a fixed-focus lens disposed coaxially on the optical axis; an image sensor disposed coaxially on the optical axis to receive image data and generate corresponding voltage signals; and a processor coupled to the image senso

A camera comprising: a close-up lens retractably disposed on an optical axis; a fixed-focus lens disposed coaxially on the optical axis; an image sensor disposed coaxially on the optical axis to receive image data and generate corresponding voltage signals; and a processor coupled to the image sensor for comparing high-frequency components of the voltage signals generated when the close-up lens is alternately on and retracted from the optical axis to determined a maximum focal value for the received image data.