White balance correcting device for an image sensing

DETAILED DESCRIPTION With such situations in mind, the present invention has been made and its object is to provide a white balance correcting device for an image sensing apparatus which can provide an accurate white balance regardless of what color combination the color filters of the image sensor have, while causing the white balance sensor to operate with its output at a proper level.
To achieve the above-described object, according to the invention, in embodiments thereof, the white balance correcting device for an image sensing apparatus is constructed in the following ways (1) to (6): (1) Use is made of a white balance sensor having color filters of the same combination as a predetermined combination of color filters which an image sensor has, signal processing means for inputting and processing an output of the image sensor and an output of the white balance sensor in a time-sharing manner, white balance coefficient computing means for computing a white balance coefficient on the basis of the processed signal output from the white balance sensor and processed by the signal processing means, and correcting means for correcting the white balance of color signals output from the image sensor and processed by the signal processing means on the basis of an output of the white balance coefficient computing means.
(2) In the way (1), means is provided for generating a timing signal to cause the reading of the white balance sensor and the computing of the white balance coefficient to be performed during the vertical blanking period.
(3) In the way (1) or (2), means is provided for controlling the amount of light entering the white balance sensor.
(4) In the way (1), means is provided for generating a timing signal to cause the reading of the white balance sensor to be performed during the horizontal blanking period and the computing of the white balance coefficient to be performed during the vertical blanking period.
(5) In the way (4), means are provided for detecting the maximum value of the output of the white balance sensor and for controlling the interval of reading of the white balance sensor in accordance with the detected value of the maximum value detecting means