The reproduction technology controls the visual perception of images based on the characteristics of human visual perception. This technology incorporates the Retinex model, which can reproduce visibility, a fundamental element of visual perception. Adding frequency band information into this model makes it possible to perform the basic processing necessary to reproduce surface properties.
It is known that the human visual system perceives an object by reducing the influence of ambient illumination components and using the object's reflectance properties. The Retinex model is a model that reproduces images based on this principle. This model first divides each pixel of an image into an illumination component and a reflection component and then enhances the reflection components to improve the visibility of the dark areas of the image. The subbands of individual objects in the image as well as the scenery can also be controlled, and therefore not only can the visibility of the entire image be improved, but its subbands can also be enhanced according to the objects and scenery in the image (Fig. 1). Moreover, when this technology is used in combination with the analysis technology, the subbands can be controlled with greater accuracy, making the image appear closer to what the human eye would see in real life.