×

Auto-focusing method

  • US 4,561,747 A
  • Filed: 06/14/1984
  • Issued: 12/31/1985
  • Est. Priority Date: 06/30/1983
  • Status: Expired due to Fees
First Claim
Patent Images

1. A method of carrying out auto-focusing by displacing a lens along the direction of an optical axis of said lens in accordance with a correlation between outputs from a pair of solid-state image sensors, said method comprising the steps of:

  • passing light through said lens and impinging the light passed through said lens on both of said solid-state image sensors;

    scanning each of said pair of solid-state image sensors thereby producing respective outputs A(n) and B(n);

    converting said outputs A(n) and B(n) into digital data A'"'"'(n) and B'"'"'(n);

    calculating Fourier transforms F1 (u), F2 (u), G1 (u) and G2 (u) using the following equations, ##EQU8## where N is the number of photoelectric elements in each of said pair of solid-state image sensors, u=0, 1, 2, . . . , M, and M is an integer which is equal to or smaller than (N/2)-1;

    calculating the following values F0, G0, F(u) and G(u) from said F1 (u), F2 (u), G1 (u) and G2 (u), ##EQU9## calculating the following value f*g, using said F0, G0, F(u) and G(u), in a timed sequence at a predetermined time period for variable t, ##EQU10## determining an amount of displacement of said lens in accordance with a value of said variable t which gives a maximum value for said f*g, whereby if said amount of displacement thus determined is outside of a predetermined range, said lens is displaced to an in-focus position according to said amount of displacement thus determined.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×