%0 Journal Article
%T Weighted Least Squares Based Detail Enhanced Exposure Fusion
%A Harbinder Singh
%A Vinay Kumar
%A Sunil Bhooshan
%J ISRN Signal Processing
%D 2014
%R 10.1155/2014/498762
%X Many recent computational photography techniques play a significant role to avoid limitation of standard digital cameras to handle wide dynamic range of the real-world scenes, containing brightly and poorly illuminated areas. In many of these techniques, it is often desirable to fuse details from images captured at different exposure settings, while avoiding visual artifacts. In this paper we propose a novel technique for exposure fusion in which Weighted Least Squares (WLS) optimization framework is utilized for weight map refinement. Computationally simple texture features (i.e., detail layer extracted with the help of edge preserving filter) and color saturation measure are preferred for quickly generating weight maps to control the contribution from an input set of multiexposure images. Instead of employing intermediate High Dynamic Range (HDR) reconstruction and tone mapping steps, well-exposed fused image is generated for displaying on conventional display devices. A further advantage of the present technique is that it is well suited for multifocus image fusion. Simulation results are compared with a number of existing single resolution and multiresolution techniques to show the benefits of the proposed scheme for variety of cases. 1. Introduction In recent years several new techniques have been developed that are capable of providing precise representation of complete information of shadows and highlights present in the real-world natural scenes. The direct 8-bit gray and 24-bit RGB representation of visual data, with the standard digital cameras in single exposure settings, often causes loss of information in the real-world scenes because the dynamic range of most scenes is beyond what can be captured by the standard digital cameras. Such representation is referred to as low dynamic range (LDR) image. Digital cameras have the aperture setting, exposure time, and ISO value to regulate the amount of light captured by the sensors. It is therefore important to somehow determine exposure setting for controlling charge capacity of the Charge Coupled Device (CCD). In modern digital cameras, Auto Exposure Bracketing (AEB) allows us to take all the images without touching the camera between exposures, provided the camera is on a tripod and a cable release is used. Handling the camera between exposures can increase the chance of miss-alignment resulting in an image that is not sharp or has ghosting. However, most scenes can be perfectly captured with nine exposures [1], whereas many more are within reach of a camera that allows 5¨C7 exposures to be
%U http://www.hindawi.com/journals/isrn.signal.processing/2014/498762/