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Tone mapping

About: Tone mapping is a research topic. Over the lifetime, 1713 publications have been published within this topic receiving 48490 citations.


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Journal ArticleDOI
TL;DR: A new tone mapping function for contrast enhancement is proposed using an optimization approach that is subject to constraints such as the output image needing to be enhanced naturally and noticeably and outperforms other contrast enhancement methods in terms of both objective and subjective criteria.
Abstract: Conventional contrast enhancement methods, including global and local enhancements, produce enhanced images with some limitations. Global contrast enhancement does not take the local characteristics into consideration, and therefore, the enhancement performance could be limited. On the other hand, a local contrast enhancement method achieves a noticeable improvement, but it generates unnatural improvement results compared with the input image. Due to the complementary characteristics of these two methods, it is hard to achieve remarkable contrast enhancement without visual artifacts. To overcome the limitations, we propose a new tone mapping function for contrast enhancement using an optimization approach that is subject to constraints such as the output image needing to be enhanced naturally and noticeably. Since contrast enhancement without artificiality is possible when the enhancement process mimics the human eye, we model the human visual perception system, and then, the model is incorporated into the proposed tone mapping function. Consequently, the contrast of the image is adaptively enhanced according to a region that is more attractive to a person. The experimental results demonstrate that the proposed algorithm outperforms other contrast enhancement methods in terms of both objective and subjective criteria.

7 citations

Book ChapterDOI
23 Oct 2011
TL;DR: A new scheme for extended visual cryptography for continuous-tone images is proposed, which mainly consists of two techniques, namely parallel error diffusion and optimum tone mapping and can quickly encrypted images with no pixel expansion and high contrast.
Abstract: Visual cryptography is a kind of cryptography that can be decoded directly by the human visual system when transparencies are stacked. Extended visual cryptography allows to print meaningful images on transparencies which can conceal the existence of "secret" in the transparencies. A lot of studies have tried to incorporate continous-tone images into extended visual cryptography. However, most of them suffer from deterioration of the resulting images. This paper proposes a new scheme for extended visual cryptography for continuous-tone images. It mainly consists of two techniques, namely parallel error diffusion and optimum tone mapping and can quickly encrypted images with no pixel expansion and high contrast. Some experimental results are shown to examine its effectiveness as well as limitation.

7 citations

Patent
12 Aug 2015
TL;DR: In this article, a method and a system for achieving HDR (High Dynamic Range) image generation and tone mapping based on an IC (Integrated Circuit) is presented, where a central processing module is communicated with an image collection module, a data storage module and an HDR processing module through a bus.
Abstract: The invention discloses a method and a system for achieving HDR (High Dynamic Range) image generation and tone mapping based on an IC (Integrated Circuit). A central processing module is communicated with an image collection module, a data storage module and an HDR processing module through a bus. At least the HDR processing module is achieved in an integrated circuit (IC) manner. The image collection module collects multiple target images of a target scene under different exposure degrees. The data storage module stores the target images collected by the image collection module, and storage a result image formed by processing of the HDR processing module. The HDR processing module obtains the target images from the data storage module, performs HDR synthesis of the multiple target images of the target scene under different exposure degrees to obtain an HDR image, performs tone mapping of the HDR image to obtain the result image of the target scene, and stores the result image of the target scene. The synthesis and the tone mapping of the HDR image are achieved through the integrated circuit (IC) manner, the real-time performance is improved, the software dependence is reduced, and the system resource cost is reduced.

7 citations

01 Jan 2009
TL;DR: In this paper, a computational framework that draws from the recent developments in computer graphics (physically based renderings and perceptually based tone mapping techniques) is utilized to generate pictorial spaces.
Abstract: Perceptual qualities of luminous environment change based on spatiality, time, and observer. This paper focuses on the complex interrelationships between architectural configurations, luminance distribution patterns, and the perception of spatial depth. A computational framework that draws from the recent developments in computer graphics (physically based renderings and perceptually based tone mapping techniques) is utilized to generate pictorial spaces. Daylighting conditions are parametrically changed and psychophysical experiments are conducted to measure the perceived distances of targets. Results reveal that luminance contrast is an effective pictorial cue that can increase the perception of the spatial depth. known to be dominant visual cues for shape perception; and lighting is used as a design strategy to reveal architectural form. However, the impact of luminance distribution patterns on depth perception has not been systematically studied; and the related design strategies are based on experiential information. In most of depth perception studies, subjects are asked to view a target in a test scene and then to adjust a target in a reference scene to match the perceived distance of the test target. Depth cues are systematically varied; and the measured difference between the perceived distances of test and reference targets allow researchers to quantify the effect of the manipulated depth cue. The dynamic character of lighting in physical environments poses challenges in terms of repeatability and manipulation of parameters in a controlled manner. Yet, with adequate modeling, visualization, and display technologies, computer generated images can provide the flexibility to simulate various lighting conditions through manipulation of input parameters including the spatial composition, materiality, lighting and the occupant's viewpoint. Therefore, computational approaches provide a unique opportunity to systematically study the impact of lighting as a pictorial cue. In this paper, physically based rendering and perceptually based tone mapping techniques are utilized to generate pictorial spaces that can provide surrogate models for physical environments to study the depth perception. The objective of this study is to demonstrate the relationship between the architectural configuration, luminance distribution patterns, time, and perceived spatial depth. METHODOLOGY The experimental setup is an elongated space that is divided into two hallways (Figure 1). Identical size floating luminous disks (12" in radius) are located at the center of each hallway as visual targets; and the camera viewpoint is set towards the center of the corridor at normal eye level. Two major variables are introduced into the experiment: The relative distance between the two disks are varied; and architectural configurations and sky conditions are changed to create different lighting conditions between the right and left hallways (Figure 2). In the base case ("no skylight" condition), the scene was illuminated with the daylight admitted from the rear end of the corridor. In other conditions, additional 5'x10' skylight was installed at 24' away from the viewpoint on one of the corridors. Different sky conditions and sun positions are simulated. The location of the left disk is fixated at 40' away from the viewpoint and it is referred as the standard disk. Right disk, referred as the comparison disk, is located at 7 different positions (located 34', 36', 38', 40', 42', 44', and 46' away from the viewpoint). The variations of disk locations are rendered under five different lighting conditions both for left and right corridors to generate a total of 70 scenes.

7 citations

Proceedings ArticleDOI
01 Dec 2011
TL;DR: Experimental results demonstrate a 169% performance improvement when adding all three instructions, with a hardware overhead of only 22%, to a 32-bit RISC-based processor for a global TM algorithm.
Abstract: Tone-mapping (TM) aims to adapt high dynamic range images to conventional display devices. TM algorithms are usually implemented on general purpose processors and graphics processing units. Such platforms may not meet performance, area, power and flexibility constraints imposed by the embedded system domain. This paper presents the design and implementation of a customized processor for a global TM algorithm. Using an architecture description language, three custom instructions to calculate luminance, logarithm and maximum luminance were added to a 32-bit RISC-based processor. The logarithm was computed using an improved Mitchell approximation. Experimental results demonstrate a 169% performance improvement when adding all three instructions, with a hardware overhead of only 22%.

7 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202330
202274
202167
202089
2019120
2018119