Patent ID: 7738031
Filing Date: 2010-06-15
Classification: H04N

Abstract:
1. An image input device comprising: an imaging device which is configured to convert an object image into electrical signals; a photographing optical unit which is configured to form the object image on the imaging device; an aperture unit which is configured to adjust a quantity of passing light by changing a size of an opening of the aperture unit over a plurality of stages; a filter unit which is configured to change transmittance of light and adjust a quantity of passing light by insertion or retraction of the filter unit with respect to an optical axis of the photographing optical unit; a shutter unit which is configured to adjust an exposure amount of the imaging device by changing exposure time; a control unit which is configured to control the aperture unit, the filter unit and the shutter unit according to object luminance; and an object determining unit which is configured to detect luminance distribution on an image plane of the object image and determine whether a high luminance object is present on the image plane of the object image, wherein when the object determining unit judges that a high luminance object is not present on the image plane of the object image, and when the opening of the aperture unit is adjusted to a first state other than a full aperture state of the aperture unit, and the filter unit is not inserted to the optical axis, the control unit performs a control that inserts the filter unit to the optical axis, and simultaneously changes the size of the opening of the aperture unit from the first state to a second state by at least one-stage of the aperture unit, and wherein when the object determining unit judges that a high luminance object is present on the image plane of the object image, and when the opening of the aperture unit is adjusted to the first state other than the full aperture state of the aperture unit, and the filter unit is not inserted to the optical axis, the control unit performs a control that changes the size of the opening of the aperture unit from the first state to a third state which is nearer the first state than the second state by at least one-stage of the aperture unit according to the object luminance, without inserting the filter unit to the optical axis, and further adjusts the opening of the aperture unit to the second state and inserts the filter unit to the optical axis simultaneously, according to the object luminance.