Patent ID: 6085040
Filing Date: 2000-07-04
Classification: G03B

Abstract:
Apparatus for regulating the amount of light emitted by a flash unit for use with an imaging device, comprising:a light source configured to illuminate a subject to be imaged by an imaging device;a light receiving element configured to receive light emitted by said light source and reflected by the subject to be imaged, and to generate a signal based on said reflected light;a light amount determination unit coupled to said light receiving element and configured to determine an amount of said reflected light received by said light receiving element based on said signal;a light amount comparison unit coupled to said light amount determination unit and configured to compare said amount of reflected light determined by said light amount determination unit with a threshold value to generate a corresponding control signal; anda light source regulator coupled to said light amount comparison unit and configured to regulate the amount of light emitted by said light source, said light source regulator including a range detector configured to detect a distance to the subject and a range error associated with calculating said distance to the subject, and a guide number setting unit configured to calculate at least one guide number based on said distance to the subject to be imaged, said range error, and an operating parameter related to the imaging device, said at least one guide number corresponding to an amount of time light is to be emitted by said light source during an imaging operation to be performed by said imaging device, said light source regulator controlling the emission of light by said light source based on said control signal and said at least one guide number.