Patent ID: 6456317
Filing Date: 2002-09-24
Classification: H04N

Abstract:
An endoscopic apparatus, comprising:an endoscope capable of being inserted into a body cavity and having an imaging device for imaging an object in the body cavity incorporated therein or mounted thereon; a light source unit for supplying illumination light to said endoscope; an amount-of-light control unit for controlling the amount of illumination light emanating from said light source unit; a signal processing unit for processing an image signal sent from said imaging device in said endoscope, said signal processing unit including first and second weighting circuits for receiving a first image signal produced by imaging said object during a first exposure time, and a second image signal that is produced by imaging said object during a second exposure time shorter than the first exposure time and that has a saturation value relative to a higher light level than the first image signal, and for applying a first weight which decreases monotonously with an increase in light level up to a light level causing said first and second image signals to have the saturation value and a second weight that increases monotonously for the first and second image signals under the condition that the sum of the first and second weights is 1, and an adding circuit for adding first and second picture signals produced by applying the first and second weights to the first and second image signals by means of said first and second weighting circuits to thus expand a dynamic range; and a light adjustment signal producing unit for, when said signal processing unit expands a dynamic range, sending a light adjustment signal to said amount-of-light control unit to increase an amount of light which emanates from said light source unit and falls on said imaging device as compared with an amount of light emanating from said light source unit in a normal state.