低露出画像に対するノイズを考慮した画像強調法

A new method of contrast enhancement for underexposed images, in which lots of noise are hidden in an image, is proposed in this paper. Under low light conditions, images taken by digital cameras have low contrast in dark or bright regions. This is due to a limited dynamic range that imaging sensors have. For these reasons, various contrast enhancement methods have been proposed so far. These methods, however, have two problems: (1) The loss of details in bright regions due to over-enhancement of contrast. (2) The noise is amplified in dark regions because they do not consider noise included images. The proposed method overcomes these problems by using the shadow-up function is applied to adaptive gamma correction with weighting distribution. A denoising filter is also used to avoid noise being amplified in dark regions. As a result, it is concluded that the proposed method allows not only to enhance contrast of dark region, but also to avoid amplifying noise, even under strong noise environments.首都大学東京, 2019-03-25, 修士（工学）首都大学東