Tone mapping

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

Learning Mandarin tone mapping codebook for voice conversion

Abstract: The phonetics properties of Chinese Mandarin features clearly demarcated syllables with tonal phonemes. A tone codebook mapping method is proposed to obtain a better performance in voice conversion of Chinese Mandarin speech than the conventional conversion method, which focuses mainly on the short-time spectral envelopes. The pitch contour of the whole Mandarin syllable is used as a unit type for pitch conversion. The syllable pitch contours are first extracted from the source and target utterances. Time normalization and moving average filtering are then performed on them. These preprocessed pitch contours are classified to generate the source and target tone code-books, and by associating them a Mandarin tone mapping codebook is finally obtained in terms of speech alignment. Experimental results show that the proposed tone codebook mapping method in voice conversion can give a good performance in Chinese Mandarin speech.

Tone mapping method of high dynamic range image/video

Abstract: A tone mapping (TM) method of high dynamic range (HDR) image/video includes the steps of A) acquiring an HDR image/video; B) processing the HDR image/video via fast global TM where each of processed pixel outputs is denoted by Pixel FG and then computing the HDR image/video via block-based GC algorithm where each of processed pixel outputs is denoted by Pixel BGC ; and C) computing the pixel outputs Pixel FG and the pixel outputs Pixel BGC that each pixel corresponds to respectively as presented by α×Pixel FG +β×Pixel BGC where the numeral values of α and β are between 0 and 1 each and α+β=1. After the computation, the result is the final output result.

Fusion of tone-mapped high dynamic range images based on objective range-independent quality maps

Abstract: Tone mapping operators for converting high dynamic range images to low dynamic range versions usually incur a loss of details compared to the original scene. As each operator performs differently in different image regions, this paper introduces a fusion technique that combines the output of several operators in a single image, based on objective quality maps that do not depend on the dynamic range of neither the input nor the output images, thus offering a better detail preservation capability compared to the case where each operator is independently applied. Results show significant improvement in the output quality obtained with the proposed technique compared to traditional tone mapping operators.

A platform for subjective image quality evaluation on mobile devices

Abstract: From content creators, to content distributors and consumer electronics industry, image quality is an important consideration both from an engineering and artistic point of view. In recent years, with the shift towards mobile multimedia, it is becoming increasingly important to be able to assess the quality of images displayed on mobile devices. In this paper we present an iOS app that makes it easy to perform subjective image quality evaluation on mobile devices. The app implements two-alternative forced choice (2AFC) test methodology, and further reduces the cognitive load of subjects performing the test by providing an easy-to-use, natural interface using the mobile device's touch screen. A simple subjective experiment comparing two tone mapping operators for High Dynamic Range (HDR) images is performed to illustrate the effectiveness of the app.

A Retinex-Based Local Tone Mapping Algorithm Using L 0 Smoothing Filter

Abstract: In this paper, we propose a novel halo-free local tone mapping algorithm using L 0 smoothing filter. Our method imitates the adaptation of the mechanism of the human visual system (HVS), which ensures a strong adaptability to the scenes of different dynamic ranges. Firstly, we will apply a global histogram adjustment method to the luminance image, which is a simple initial global adaptation; secondely, we will demonstrate how the luminance image is remapped by a retinex-based local tone mapping method. During the estimation of illumination, a L 0 smoothing filter is used instead of Gaussian filter to compress the contrast while reducing the halo artifacts; and finally, through the color correction, we will show how the tone-mapped RGB image is obtained. According to our experimental results, the proposed method outperforms the state-of-art tone mapping algorithms in color rendition and detail preservation.