Adaptive contrast adjustment for postprocessing of tone mapped high dynamic range images
19 May 2013-pp 1103-1106
TL;DR: Experimental results confirm that the proposed adaptive solution always improves upon the contrast achieved from whatever given T MO parameter settings in the tested images, so it helps to achieve the results of a more optimal TMO parameter setting without the human input.
Abstract: Tone mapping operators (TMOs) employed to visualize high dynamic range (HDR) content on conventional low dynamic range (LDR) devices suffer from two major drawbacks. First, none of them can faithfully reproduce all the contrast present in HDR images. Second, most of them require one or more parameters which are mostly content specific and their optimal values can be set only via subjective testing. To address these issues, this paper proposes that `quality driven' adaptive contrast enhancement is a practical solution. This is achieved by enhancing the contrast adaptively based on the loss of contrast between the HDR and tone mapped image. Experimental results confirm that the proposed adaptive solution always improves upon the contrast achieved from whatever given TMO parameter settings in the tested images. So it helps to achieve the results of a more optimal TMO parameter setting without the human input.
Citations
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TL;DR: A subjective experiment attempting to determine users’ preference with respect to these two types of content in two different viewing scenarios—with and without the HDR reference shows that the absence of the reference can significantly influence the subjects' preferences for the natural images, while no significant impact has been found in the case of the synthetic images.
Abstract: The popularity of high dynamic range (HDR) imaging has grown in both academic and private research sectors. Since the native visualization of HDR content still has its limitations, the importance of dynamic range compression (i.e., tone-mapping) is very high. This paper evaluates observers’ preference of experience in context of image tone-mapping. Given the different nature of natural and computer-generated content, the way observers perceive the quality of tone-mapped images can be fundamentally different. In this paper, we describe a subjective experiment attempting to determine users’ preference with respect to these two types of content in two different viewing scenarios—with and without the HDR reference. The results show that the absence of the reference can significantly influence the subjects’ preferences for the natural images, while no significant impact has been found in the case of the synthetic images. Moreover, we introduce a benchmarking framework and compare the performance of selected objective metrics. The resulting dataset and framework are made publicly available to provide a common test bed and methodology for evaluating metrics in the considered scenario.
20 citations
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TL;DR: In this article , a block-priority modification of the adaptive histogram equalization method is proposed to reduce the computational complexity of transforming the dynamic range of infrared images, a modification is based on the division of the set of image blocks into two subsets of high-priority and low-priority blocks depending on their brightness statistical properties.
Abstract: Objectives. The problem of reducing the dynamic range of infrared images for their reproduction on display devices with a narrow dynamic range is considered. The method of local image histogram equalization based on the integral distribution function of brightness is investigated. To transform the brightness of a pixel, this method uses an approximation of the local alignment values of the nearest blocks of pixels of original image. This in-creases the local contrast of the image, but leads to high computational complexity, which is increasing while block size decreases. The aim of the work is to reduce the computational complexity of adaptive equalization and compression of infrared image histograms while reducing their dynamic range.Methods. Image processing methods are used.Results. To reduce the computational complexity of transforming the dynamic range of infrared images, a block-priority modification of the adaptive histogram equalization method is proposed. The modification is based on the division of the set of image blocks into two subsets of high-priority and low-priority blocks depend-ing on their brightness statistical properties. When interpolating pixel values, high-priority blocks use local alignment values, and low-priority blocks use global alignment values. As a result, the total number of alignment vectors is reduced in proportion to the ratio of subsets sizes and the computational complexity of the dynamic range transformation is reduced.Conclusion. When changing the ratio of the number of high-priority blocks of infrared image pixels to the number of all blocks in the range of 0.25–0.75, the proposed algorithm is more efficient than global and adaptive histogram equalization algorithms.
References
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TL;DR: The work presented in this paper leverages the time-tested techniques of photographic practice to develop a new tone reproduction operator and uses and extends the techniques developed by Ansel Adams to deal with digital images.
Abstract: A classic photographic task is the mapping of the potentially high dynamic range of real world luminances to the low dynamic range of the photographic print. This tone reproduction problem is also faced by computer graphics practitioners who map digital images to a low dynamic range print or screen. The work presented in this paper leverages the time-tested techniques of photographic practice to develop a new tone reproduction operator. In particular, we use and extend the techniques developed by Ansel Adams to deal with digital images. The resulting algorithm is simple and produces good results for a wide variety of images.
1,593 citations
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TL;DR: In this article, the tone reproduction problem is also considered, which maps the potentially high dynamic range of real world luminances to the low dynamic ranges of the photographic print, which is a classic photographic task.
Abstract: A classic photographic task is the mapping of the potentially high dynamic range of real world luminances to the low dynamic range of the photographic print. This tone reproduction problem is also ...
582 citations
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TL;DR: This work takes as an input a high dynamic range image and maps it into a limited range of luminance values reproducible by a display device and follows functionality of HVS without attempting to construct its sophisticated model.
Abstract: A new method is presented that takes as an input a high dynamic range image and maps it into a limited range of luminance values reproducible by a display device. There is significant evidence that a similar operation is performed by early stages of human visual system (HVS). Our approach follows functionality of HVS without attempting to construct its sophisticated model. The operation is performed in three steps. First, we estimate local adaptation luminance at each point in the image. Then, a simple function is applied to these values to compress them into the required display range. Since important image details can be lost during this process, we then re-introduce details in the final pass over the image.
371 citations
"Adaptive contrast adjustment for po..." refers methods in this paper
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Book•
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TL;DR: This book provides a practical introduction to the emerging new discipline of high dynamic range imaging that combines photography and computer graphics by providing detailed equations and code that gives the reader the tools needed to experiment with new techniques for creating compelling images.
Abstract: Imaging techniques seek to simulate the array of light that reaches our eyes to provide the illusion of sensing scenes directly. Both photography and computer graphics deal with the generation of images. Both disciplines have to cope with the high dynamic range in the energy of visible light that human eyes can sense. Traditionally photography and computer graphics took different approaches to the high dynamic range problem. Work over the last ten years though has unified these disciplines and created powerful new tools for the creation of complex, compelling and realistic images. This book provides a practical introduction to the emerging new discipline of high dynamic range imaging that combines photography and computer graphics. By providing detailed equations and code, the book gives the reader the tools needed to experiment with new techniques for creating compelling images. A supplemental website contains downloads and additional information.
287 citations
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