Tone mapping

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

A fixed-point tone mapping operation for HDR images in the RGBE format

Abstract: A fixed-point tone mapping operation (TMO) instead of a floating-point TMO is proposed in this paper. A TMO generates a low dynamic range (LDR) image from a high dynamic range (HDR) image. Since pixel values of an HDR image are generally expressed in a floating-point data format, e.g. RGBE and OpenEXR, a TMO is also implemented in floating-point arithmetic in conventional approaches. However, it requires a huge computational cost, even though a resulting LDR image is expressed in simple integers. The proposed TMO is implemented with only fixed-point arithmetic. As a result, the proposed method reduces a computational cost. Experimental results shows the PSNR of LDR images in the proposed method are comparable to those of the conventional methods.

A Novel Tone Mapping Method for High Dynamic Range Image by Incorporating Edge-Preserving Filter Into Method Based on Retinex

Abstract: A tone mapping method for high dynamic range image is proposed to prevent the halo artifacts, which is easy to be produced in traditional method based on the Retinex theory in handling high dynamic range(HDR) image. Our method is based on the Retinex theory. The novelties of our method is first to employ a local e dge-preserving filter for the estimation of the illuminatio n, which can smooth out the small-scale details while the large-scale edges are retained. Second, the filter is incorporated into the method based on MSR algorithm, in which the Gaussian filter is replaced by thi s filter in order to prevent the halo artifacts and a multi-sca le operation is applied for preserving more details. Finally, a post-pro cessing step is adopted to compress the dynamic range and prevent the underexposure or overexposure. We tested our method on a variety of HDR images and compared it with other typical methods. The experimental results show that the proposed method can not only prevent the halo artifacts, but also can get higher contr ast and more clearly details.

Reproducing apparatuses, reproducing method and recording medium

Abstract: PROBLEM TO BE SOLVED: To provide a reproducing apparatuses capable of displaying graphics of a wide dynamic range of brightness with an appropriate brightness.SOLUTION: An optical disk records: tone_mapping_info that includes a piece of HDR information representing the characteristics of luminance of a HDR graphic which is a graphic of a second luminance range wider than and different from the first luminance range; a Tone_map stream including tone_mapping_info which is a piece of tone mapping definition information used when performing luminance conversion from the HDR graphic to an STD graphic which is a graphic of a first luminance range; and a graphic stream of the HDR graphic. The art is applicable to a recording medium for recording graphics.

Multi-Scale Retinex with Color Restoration and Detail Compensation

Abstract: An algorithm is proposed to solve the problem that the results of multi-scale Retinex with color restoration(MSRCR) are prone to have fuzzy detail and color distortion when it is used to separate lightness components.The proposed algorithm utilizes Retinex theory to divide the luminance into the components of lightness and reflectance.Then,the boundary of image is compensated by adding the detailed information that is extracted from lightness using bilateral filtering.The base-layer is extracted from the components of reflectance,and then is adaptively adjusted so as to compress the dynamic range of the high dynamic range image.Furthermore,the method can prevent color distortion and make the target images achieve better visual effect through color correction.Experimental results show that the proposed algorithm has better effect on dynamic range compression than both MSRCR and bilateral filtering methods have,and prevents halo artifacts,and that not only details but also color can be reproduced by the algorithm in visual point of view.

Revisited histogram equalization as HDR images tone mapping operators

Abstract: High Dynamic Range (HDR) image provides higher perceptual quality such that it appears considerably more realistic and attractive for the human observer. Since most of current screens are Low Dynamic Range (LDR) screens, lots of researches have been proposed to design tone mapping algorithms converting the HDR images into a range that is suitable to display these tone mapped images on standard LDR screens. For this purpose, this paper first investigates the pixels distribution in the HDR image through the study of various traditional Histogram Equalization (HE) algorithms which were originally developed to improve the visual quality of LDR images such as the contrast enhancement of the latter. Moreover, a modification of the Histogram Adjustment based Linear to Equalized Quantizer (HALEQ), developed for HDR images, is proposed. Simulation results show that the proposed modification preserves more details than the original version of the algorithm in most parts of the HDR image.