Multi-Pattern Auto White Balance Technology
When shooting scenes that include multiple light sources, such as sunlight and shade or flash, light sources are recognized automatically and the image is separated into different areas. White balance is adjusted separately in each area according to the different light sources to achieve optimal color reproduction.
Automatic recognition of sunlight and shade areas / strong and weak flash for optimal color reproduction
If WB parameters are set for the entire image, they are set either to the background sunlit area or to people in the shade. Then, the color tone of the resulting picture is unnatural. The new method, called Multi-Pattern Auto White Balance (Multi-Pattern AWB) or Multi-pattern AUTO, sets WB parameters for sunlight and shade areas separately. Therefore the colors of both background sunlit areas and shade areas are reproduced properly.
Multi-Pattern AWB automatically sets different WB parameters for areas of different flash light intensity. As shown in Photo 1 (a), because WB is adjusted to the background area and the parameters are set for the entire image, the color of people's faces is whitish blue, where the flash is strong. In Photo 1(b), Multi-Pattern AUTO sets WB parameters for the background based on an incandescent (bulb) light source and sets WB parameters for people’s faces based on strong flash exposure. Colors of both background and people are thus properly reproduced.
|(a)Set WB parameters to background||(b)Multi-Pattern AUTO|
Advanced area recognition function and high-performance classifier data
High-quality, robust classifier data is necessary for recognition. The classifier data is gathered from an accumulated knowledge base, using many digital camera images of sunlight and shade areas. The classifier data is kept small and manageable, so that the camera can recognize sunlight and shade areas quickly and accurately to realize Multi-Pattern AWB.
This technology is applied to Ricoh's current digital camera lineup. The method yields optimal color reproduction for scenes involving people, which is difficult for conventional WB methods to achieve.
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