Title:
シーンの照度レベルに鈍感なオートフォーカス方法
Document Type and Number:
Japanese Patent JP4484513
Kind Code:
B2
Abstract:
A method, system and program product for providing automatic focus adjustment for an image device, comprising the steps of: differentiating an image along some axis to obtain a difference image; computing a variance of the difference image; determining a noise contribution to the variance; subtracting the noise contribution from the variance; using the adjusted noise variance as a factor in making the automatic focus adjustment. In a preferred embodiment, the variance is normalized, and the noise contribution is determined by determining the shot noise and the read noise.
Inventors:
Bear, Richard Elle
Application Number:
JP2003501192A
Publication Date:
June 16, 2010
Filing Date:
May 24, 2002
Export Citation:
Assignee:
HEWLETT-PACKARD COMPANY
International Classes:
G02B7/28; G03B13/36; G02B7/36; H04N5/232; H04N101/00
Domestic Patent References:
| JP2000354179A | ||||
| JP6268895A | ||||
| JP8166534A | ||||
| JP5300421A | ||||
| JP1209885A | ||||
| JP10013749A |
Attorney, Agent or Firm:
Shoichi Okuyama
Arihara Koichi
Matsushima Tetsuo
Arihara Koichi
Matsushima Tetsuo