Photo composition feedback and enhancement exploiting spatial design categories and the notan dark-light principle

Abstract In this chapter, we present techniques to provide composition feedback and enhancement for photographs. In order to suit mobile applications, we have designed systems requiring minimal input from the users. The essence of composition is to create unity in a picture, which includes the balance of visual elements from many aspects. We hereby explore several fundamental concepts in composition and develop our new methods accordingly. Albeit much exploited by artists, these concepts have barely crossed over to multimedia or computer vision research. First, we have developed a tool to categorize images by spatial design into diagonal, horizontal, vertical, and centered composition types. Composition in this regard is known to be well associated with aesthetics and emotional response. For instance, placing visual elements diagonally creates a sense of movement; and horizontal placement tends to convey tranquility. This composition analysis tool enables the retrieval of highly aesthetic exemplar images from the corpus which are similar in content and composition to the snapshot. Second, the arrangement of dark and light masses in a picture, referred to as Notan in visual art, is a crucial factor in composition. We propose an approach to adjust the tonal values in an image, targeting directly at achieving an aesthetically more appealing Notan. This method addresses