초록 ▼

A focus detection device which repeatedly calculates correlations between first and second image signals representing light intensity distributions on first and second image sensor arrays by shifting one of the image signals relative to the other to find an amount of shift affording the highest corr

A focus detection device which repeatedly calculates correlations between first and second image signals representing light intensity distributions on first and second image sensor arrays by shifting one of the image signals relative to the other to find an amount of shift affording the highest correlation includes shift range restriction means for restricting the shift range for the present correlation calculation in accordance with the amount of shift found through the last correlation calculation to afford the highest correlation. The shift range restriction is inhibited when the result of the last correlation calculation was not reliable indicating an infeasible condition of the focus detection.

대표청구항 ▼

A focus detection device comprising: an objective lens; optical means for forming first and second images of an object so that the relative position of said first and second images varies with the focus condition of said objective lens; first and second image sensor arrays for sensing said first and

A focus detection device comprising: an objective lens; optical means for forming first and second images of an object so that the relative position of said first and second images varies with the focus condition of said objective lens; first and second image sensor arrays for sensing said first and second images and for producing first and second image signals representing the light intensity distributions of said first and second images, respectively; calculation means for shifting one of said first and second image signals relative to the other to calculate correlations between said first and second image signals and thereby to find an amount of shift affording the highest correlation; focus condition signal producing means for producing a focus condition signal representing the focus condition of said objective lens in accordance with said amount of shift found to afford the highest correlation; control means for repeatedly operating said calculation means; shift range restriction means for restricting the range of shift for a present correlation calculation by said calculation means, in accordance with said amount of shift found through the last correlation calculation by said calculation means, to afford the highest correlation; reliability determination means for determining the reliability of a correlation calculation of said calculation means; and inhibition means for inhibiting the operation of said shift range restricting means, to permit said calculating means to calculate correlation over its entire permissible range of shift when the determination by said reliability determining means indicates that the calculation result of said calculation means was not reliable.