BACKGROUND

The inventive concept relates to image processing methods and devices. More particularly, the inventive concept relates to image processing methods and devices performing auto white balance on image data.

Auto white balance (AWB) is an image processing function that may be used to control the imaging and/or reproduction (e.g., display or printing) of an image, such that “white” (or lighter or brighter) portions or objects of the image may be appropriately visualized as being white, despite variations in image staging, color and/or image illumination (e.g., sunlight, fluorescent or incandescent lights, etc.). Effective AWB is often necessary to correct imaging and/or image reproductions where reproduced white portions or objects otherwise exhibit poor or undesirable coloring (e.g., bluish or reddish tinting of white portions).

This necessity arises from the recognize phenomenon that while the human eye is able to visually adapt to variations in staging, colors, and/or illumination, electronic imaging apparatuses (e.g., cameras) do not possess an innate ability to visually adapt in order to correct of compensate for varying image conditions. AWB is a technology commonly used to correct or compensate for various phenomena characterized by an undesired color shift where a color is changed in cameras depending on illuminants.

SUMMARY

The inventive concept provides an image processing method and device for auto white balance.

According to an aspect of the inventive concept, there is provided an auto white balance method performed by an image signal processor, the auto white balance method including; dividing image data into a plurality of partition cells, calculating a skin tone estimation value for the image data, and selecting outliers for detection of a white point of the image data based on at least one of the plurality of partition cells and the skin tone estimation value.

According to an aspect of the inventive concept, there is provided an auto white balance method including; dividing image data including a face image into a plurality of partition cells, calculating a skin tone estimation value based on selected partition cells included in the face image, and selecting a gray candidate cluster for performing auto white balance on the image data based on at least one of the selected partition cells and the estimation value.

According to an aspect of the inventive concept, there is provided an auto white balance method performed by an image signal processor, the auto white balance method including; dividing the image data including a face image into a plurality of partition cells, selecting partition cells associated with at least a portion of the face image from the plurality of partition cells, calculating a skin tone estimation value based on at least one of the selected partition cells, further selecting from among the selected partition cells those selected partition cells included in a first gray candidate cluster defined in a color space associated with the image data, and selecting a second gray candidate cluster for performing the auto white balance on the image data, based on the further selected partition cells included in the first gray candidate cluster and the skin tone estimation value.

According to an aspect of the inventive concept, there is provided an auto white balance method performed by an image signal processor, the auto white balance method including; dividing image data including a face image into a plurality of partition cells, detecting a face region associated with the face image from the image data, selecting partition cells associated with the face image from among the plurality of partition cells to define a set of selected partition cells, further defining the set of selected partition cells to define a set of further selected partition cells, and calculating a skin tone estimation value for the image data from the further selected partition cells.

