Human-visual-system-inspired tone mapping algorithm for HDR images

Rizzi, Alessandro; Gatta, Carlo; Piacentini, Benedetta; Fierro, Massimo; Marini, Daniele

doi:10.1117/12.525777

Cited by 11 publications

(6 citation statements)

References 21 publications

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“…43,44 In this case, we use the term prefiltering. Prefiltering is a good solution when the original luminance range is known or when images are stored in a high dynamic range ͑HDR͒ format.…”

Section: Tone Mapping Solutionsmentioning

confidence: 99%

Postfiltering for color appearance in synthetic image visualization

Marini

Rizzi

Rossi

2004

J. Electron. Imaging

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In the photorealistic image synthesis process, an accurate approximation of the spectral light radiance field of a synthetic scene is carefully reproduced, with the goal of generating a synthetic image that is indistinguishable from the actual one. The paradigm of photorealism requires a comparison of the real scene and its synthetic reproduction, and the two visual representations should be studied under the same conditions to make a correct comparison and evaluate the degree of accuracy. To reproduce the same observing conditions, we need to define a sort of synthetic observer (given the impossibility to enter into a synthetic world) to compensate the deep differences in the viewing conditions, between the real and synthetic images. Various solutions have been proposed to this end; most of them are based more on perceptive measures of the human visual system (HVS) under controlled conditions, rather than on the HVS behavior under real conditions, e.g., observing a natural image and not a controlled black and white or colored pattern. Besides the comparison problem, difficulties can arise from the visualization phase, whose purpose is to display the final results of the simulation model on a monitor screen or printed paper. This is known as the tone reproduction problem, and in most cases, one has to find the best solution to compress an extended dynamic range of the computed light field into the limited range of displayable colors. Several solutions have been proposed to solve this problem. On the contrary, no mapping is usually made in case of low luminance and extremely limited dynamic range images, and consequently photorealism and visual appearance are lost. We propose a working hypothesis to solve the appearance and the tone reproduction problems in the synthetic image generation, integrating the Retinex model into the photorealistic image synthesis context, including in this way a model of the HVS in the image synthesis process.

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Section: Tone Mapping Solutionsmentioning

confidence: 99%

Postfiltering for color appearance in synthetic image visualization

Marini

Rizzi

Rossi

2004

J. Electron. Imaging

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“…From the many existing contrast models, we here use the most relevant and applicable ones (Simone et al 2012). They are generally based on two distinguishable concepts of the human visual system: the difference of gaussians (DoG) and the retinal-like subsampling of contrast (Rizzi et al 2004;Simone et al 2012;Tadmor and Tolhurst 2000). The first feature was adopted and modified by Tadmore and Tolhurst in 2000, who investigated the usefulness of a DoG based receptive field model for predicting the perception of contrast in natural scenes, as experienced by the retinal ganglion cells and the neurons in the lateral geniculate nucleus (LGN).…”

Section: State Of the Artmentioning

confidence: 99%

“…Later Joulan et al extended the DoG model by including a multi-scale spatial filter based on parameters determined by the contrast sensitivity function (CSF). The second feature was adopted by Rizzi et al in 2004 to determine a contrast measure in digital images. In 2012, Simone et al extended and combined these two features into a weighted level framework model.…”

Section: State Of the Artmentioning

confidence: 99%

Road Marking Contrast Threshold Revisited

Spieringhs

Smet

Heynderickx

et al. 2021

LEUKOS

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Sufficient contrast between road surface and road markings is key for a safe and comfortable driving experience. This calls for a comprehensive and well established contrast (threshold) model, which ideally results in a single contrast threshold value independent of object angular size or road luminance. The contrast threshold model introduced by Adrian is still commonly used in road lighting. More recently, new contrast metrics that also predict supra-threshold contrast visibility have been proposed, but the corresponding visibility thresholds are not yet known. In the present study, participants are presented a rendering of a highway, including road marking arrows of various size and luminance and were asked to indicate the direction of the arrow. The luminance of the road surface, acting as background for the markings, was varied too. Due to the very low luminance values and the very small differences in luminance, measurement accuracy and calibration issues require special attention. The results show good agreement with Adrian's visibility model (R 2 = 0.75) in terms of luminance contrast, background luminance and size. In addition, we used our experimental data to define contrast thresholds for several other existing image based contrast models. Unfortunately, it seems to be impossible to state one unique threshold contrast value independent of object angular size and road luminance.

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“…Some of these approaches for tone mapping are [28]- [31] and, more recently, the probabilistic approaches introduced in [32] and [33]. Rizzi et al [34] try to apply knowledge about the human visual system to perform the tone mapping in a related way. A perceptual evaluation of some tone mapping operators is presented in [35].…”

Section: Related Workmentioning

confidence: 99%

Adaptive High Dynamic Range for Time-of-Flight Cameras

Conde

Hartmann

Loffeld

2015

IEEE Trans. Instrum. Meas.

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The limited dynamic range of conventional digital cameras is a well-known problem. A common solution is to apply high-dynamic-range (HDR) techniques over several images acquired using different exposure times. Time-of-flight (ToF) cameras using a photonic mixer device (PMD) are not an exception, since the dynamic range of its dual pixels is also limited. Furthermore, in this case, the saturation of the pixel channels leads to wrong depth measurements. An appropriate solution is the suppression of background illumination (SBI) system designed by the PMD. This system actually extends the dynamic range of the camera by hardware, but it also introduces noise when activated. In this paper, we present an adaptive HDR (AHDR) solution to the problem for the ToF case that overcomes the limited dynamic range of the system, allowing sensing along a theoretically infinite dynamic range with the only limitations of the power of the illumination system and the decay of the SNR with higher distances or lower illumination intensities. Our method is able to detect and segment relevant scene regions responsible for unexpected saturation, i.e., close foreground objects, from the rest of the scene and adjust the exposure times of the acquired images considering them. The results show a reduction in detail losses and a higher SNR in the AHDR raw images, with respect to single acquisitions. This results in a dramatic depth error reduction and effective axial resolution improvement in critical areas, while keeping a high frame rate. In addition, the SBI-related noise is eliminated.Index Terms-High dynamic range (HDR), noise reduction, photonic mixer device (PMD), suppression of background illumination (SBI), time-of-flight (ToF).

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Human-visual-system-inspired tone mapping algorithm for HDR images

Cited by 11 publications

References 21 publications

Postfiltering for color appearance in synthetic image visualization

Postfiltering for color appearance in synthetic image visualization

Road Marking Contrast Threshold Revisited

Adaptive High Dynamic Range for Time-of-Flight Cameras

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