Tone-mapping functions and multiple-exposure techniques for high dynamic-range images

Efficient Operator for Local Energy Measurements to Enhance an Image Signal

“…This image belongs to a class of a so-called High-Dynamic Range (HDR) images [11], since it has a very high global contrast ratio (87,962:1). For a correct rendering, it requires a global tone mapping [1], [4] in addition to the local contrast enhancement [5]- [8], [11]- [17]. In this particular case, the required level of global tone mapping is extremely high, We can observe that all metrics provide high level of details in the texture regions, increase depth of field and prevent disturbing "halo" artifacts.…”

“…Function f is non-linear and can have any form that combines previously mentioned parameters in a beneficial manner. For example, we have already discussed a way to improve the noise performance of our algorithm [4] by limiting the original contrast gain by introducing the Maximum gain limit and a linear response of a gain function to the LD, G ∝ 1/LD, (see Fig. 1(b)).…”

“…In real-time video applications, the computation complexity should be low, which poses a significant design problem and has a clear impact on the possible solution for the image quality optimization: whatever the adopted solution is, simplicity and efficiency are a prerequisite. Global contrast control algorithms can be applied [1]- [4], however, there are often more complex situations, where contrast can be poor in some parts of the image, but adequate in other parts, or when the overall contrast is good but local contrast is low. Besides this, low-quality video footage originating from lowquality capturing devices poses significant challenges if an acceptable output video quality is required.…”

Normalized tone-mapping operators for color quality improvement in 3DTV

“…In the case of a 50-inch 3DTV used in a previous study [10], the intensity difference of the Blue-channel between reproduction modes was less than 50% those of the Greenchannel, and since the blue does not dominate at lower intensities, tone-mapping operators (TMO) are generated for the Red and Green-channels with (1). 2 3 ( )…”

Image Quality Assessment of Tone Mapped Images

“…Dynamic range (DR) of conventional display devices is on the order of 100 to 1 whereas that of real scene is larger than 10,000 to 1 [1], [2]. Digital still and video cameras have the capability to acquire the DR larger than 100 to 1 to satisfy acceptable quality, with less noise interference and natural contrast representation [2]- [4]. Moreover, to obtain a perceptually high-quality image, consumer digital cameras need to capture real scene as human eyes do.…”