Tone Mapping Method Based on the Least Squares Method

Zhao, Lanfei; Li, Guoqing; Wang, Jun

doi:10.3390/electronics12010031

Cited by 5 publications

(3 citation statements)

References 19 publications

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“…The R-square and RMSE were 1 and 0.00573, respectively. The fourth-order polynomial fitting of standard conductivity data and AD value is carried out by the least square method 15 . The fitting equation is as follows:…”

Section: Sensor Calibrationmentioning

confidence: 99%

Development and application of seven-electrode temperature and salinity sensor

ZHANG,

et al. 2024

Ninth International Symposium on Sensors, Mechatronics, and Automation System (ISSMAS 2023)

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The temperature and salinity of seawater are essential physical parameters for marine science. The measurement of conductivity is an important means of salinity measurement. In this article, seven electrodes are used to design a temperature and salinity sensor. The sensor detects voltage signal and current signal in strong marine noise environments using lock-in amplifier technology to improve the measurement accuracy of seawater conductivity. A seven-electrode temperature and salinity sensor and a Seabird SBE37-SI temperature and salinity sensor are used for laboratory comparison, the temperature measurement error and the conductivity measurement error are within ±0.005℃ and ±0.0003s/m. The temperature and salinity sensor is installed on an ocean buoy, and offshore testing is carried out. The test data shows that the sensor's measurement data is accurate and reliable, and can be used to measure the temperature, conductivity, and salinity of seawater.

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Section: Sensor Calibrationmentioning

confidence: 99%

Development and application of seven-electrode temperature and salinity sensor

ZHANG,

et al. 2024

Ninth International Symposium on Sensors, Mechatronics, and Automation System (ISSMAS 2023)

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“…However, global TMOs may result in insufficient local contrast, leading to the loss of some local details. Local TMOs, such as TMOs based on Retinex theory [13], the image color appearance model [14], and the TMO proposed in [15], adjust the tone curve based on local information around a pixel. These TMOs have been extensively developed to meet the requirements of many applications.…”

Section: Introductionmentioning

confidence: 99%

A Low-Latency Noise-Aware Tone Mapping Operator for Hardware Implementation with a Locally Weighted Guided Filter

Liang,

Yan,

Wang

et al. 2024

Symmetry

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A tone mapping operator (TMO) is a module in the image signal processing pipeline that is used to convert high dynamic range images to low dynamic range images for display. Currently, state-of-the-art TMOs typically take complex algorithms and are implemented on graphics processing units, making it difficult to run with low latency on edge devices, and TMOs implemented in hardware circuits often lack additional noise suppression because of latency and hardware resource constraints. To address these issues, we proposed a low-latency noise-aware TMO for hardware implementation. Firstly, a locally weighted guided filter is proposed to decompose the luminance image into a base layer and a detail layer, with the weight function symmetric concerning the central pixel value of a window. Secondly, the mean and standard deviation of the basic layer and the detail layer are used to estimate the noise visibility according to the human visual characteristics. Finally, the gain for the detail layer is calculated to achieve adaptive noise suppression. In this process, luminance is first processed by the log2 function before being filtered and then symmetrically converted back to the linear domain by the exp2 function after compression. Meanwhile, the algorithms within the proposed TMO were optimized for hardware implementation to minimize latency and cache, achieving a low latency of 60.32 μs under video specification of 1080 P at 60 frames per second and objective metric smoothness in dark flat regions could be improved by more than 10% compared to similar methods.

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“…Beyond that, Dargo [10] first proposed an adaptive logarithmic tone mapping curve. Zhao et al [11,12] proposed the effective TMOs by using localized contrast correction and Retinex [13]. Mantiuk et al [14] used the contrast perturbation of the HVS model as the weight to construct the tone mapping operator, and Khan et al [15] adjusted the image luminance histogram based on the just noticeable difference (JND) and used a look-up table to construct the mapping.…”

Section: Introductionmentioning

confidence: 99%

Domain-Aware Adaptive Logarithmic Transformation

Fang

Feng

2023

Electronics

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Tone mapping (TM) aims to display high dynamic range scenes on media with limited visual information reproduction. Logarithmic transformation is a widely used preprocessing method in TM algorithms. However, the conventional logarithmic transformation does not take the difference in image properties into account, nor does it consider tone mapping algorithms, which are designed based on the luminance or gradient-domain features. There will be problems such as oversaturation and loss of details. Based on the analysis of existing preprocessing methods, this paper proposes a domain-aware adaptive logarithmic transformation AdaLogT as a preprocessing method for TM algorithms. We introduce the parameter p and construct different objective functions for different domains TM algorithms to determine the optimal parameter values adaptively. Specifically, for luminance-domain algorithms, we use image exposure and histogram features to construct objective function; while for gradient-domain algorithms, we introduce texture-aware exponential mean local variance (EMLV) to build objective function. Finally, we propose a joint domain-aware logarithmic preprocessing method for deep-neural-network-based TM algorithms. The experimental results show that the novel preprocessing method AdaLogT endows each domain algorithm with wider scene adaptability and improves the performance in terms of visual effects and objective evaluations, the subjective and objective index scores of the tone mapping quality index improved by 6.04% and 5.90% on average for the algorithms.

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Tone Mapping Method Based on the Least Squares Method

Cited by 5 publications

References 19 publications

Development and application of seven-electrode temperature and salinity sensor

Development and application of seven-electrode temperature and salinity sensor

A Low-Latency Noise-Aware Tone Mapping Operator for Hardware Implementation with a Locally Weighted Guided Filter

Domain-Aware Adaptive Logarithmic Transformation

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