In a conventional camera, a depth of lens must be changed by exchanging a lens or changing the number of apertures, in order to utilize an all-focus or out-focus function. However, a structure of lens exchange or an aperture integrated lens has a large size, and thereby has problems in applying to a camera of mobile phone or compact camera according to the trend of miniaturization.
Further, the out-focusing function may be utilized by dividing an image obtained by a camera having a high depth of focus into a portion to be focused and background by using a segmentation technology and applying a blur filter to the background. However, there are problems in obtaining a high quality photo because an error may be generated in dividing a subject and background, and deterioration of image quality may be generated when applying the blur filter due to the limitation of segmentation technology. The all-focus function may be utilized by using an EDoF (Extended Depth of Focus) technology which expands the depth of effect through image processing. However, this method is seldom used due to the deterioration of image quality. Further a re-focusing function may be utilized by using a camera obtaining information of light path, such as a plenoptic camera and array camera. However, this method has problems in obtaining a high resolution photo.
Accordingly, developments in technology providing focusing functions such as an all-focus, out-focus, and re-focus function are necessary for the camera of mobile phone and compact camera according to the trend of miniaturization.