Improving Color Accuracy of Colorimetric Sensors

Kirchner, Eric; Koeckhoven, Pim; Sivakumar, Keshav

doi:10.3390/s18041252

Cited by 8 publications

(5 citation statements)

References 8 publications

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“…The color accuracy of the NCS ColorPIN II can also be expressed as the alignment with 20 to 80 times more expensive spectrophotometers, and we have shown before that this is often better than dE CMC(1:1) <2.0 22 . Below we will see that this accuracy makes it well suitable for measuring the colors in this investigation.…”

Section: Quantitative Approachmentioning

confidence: 58%

Quantifying the color palettes of Naghsh‐e Jahan Square in Isfahan

Mohammadgholipour

Kirchner

Salleh

2020

Color Research & Application

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In the 1960s, Jean‐Philippe Lenclos introduced a structured methodology for determining the color palettes of urban environments. After half a century, this method is widely used all over the world. Since this process contains subjective and time‐consuming steps, we propose a quantitative improvement of Lenclos' methodology by introducing a fully digital procedure. This removes observer subjectivity and dependence on local illumination conditions. We applied the digital process to the four monumental buildings of Naghsh‐e Jahan Square in Isfahan, a masterpiece of world architecture. The resulting color palettes are more accurate than those obtained in earlier studies. We obtained more accurate color coordinates, characterized by a wider color gamut, and quantified color variations within buildings and between monuments as well.

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Section: Quantitative Approachmentioning

confidence: 58%

Quantifying the color palettes of Naghsh‐e Jahan Square in Isfahan

Mohammadgholipour

Kirchner

Salleh

2020

Color Research & Application

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“…Although there exist special research cameras that can provide such information, they are expensive and not available to the general user. Examples where colorimetrically accurate recording is desired include the measurement of textile patterns, 1 , 2 paint color matching, 3 art archival, 4 , 5 and medicine 6 , 7 . For such applications, being able to use an existing consumer camera would provide an affordable option.…”

Section: Introductionmentioning

confidence: 99%

Determination and use of external color filter for improved camera colorimetry

Vrhel¹,

Trussell

2023

J. Electron. Imag.

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.Most digital cameras have spectral characteristics that make it impossible for the camera to provide accurate colorimetric information of a recorded scene. We extend previous work on using multiple filtered exposures by the use of a newly available capability of creating manufacturable filters using online software. Multiple criteria are considered in the determination of an optimal color filter on a training dataset. These criteria include the Vora-Value, figure of merit (FOM), training average ΔE, and training maximum ΔE. Our method includes the use of a realistic imaging noise model. We use two optimization methods: minimum mean square error (MMSE), which requires knowledge of the color sensitivities of the camera’s internal RGB filters and knowledge of the covariance matrices of the data ensemble and the noise, and a pseudoinverse method that uses only the recorded data and knowledge of the values of the training data. Filters were selected using the training data and the performance is measured on independent testing data. The results from both optimization methods show that filters chosen using the training ΔE criteria consistently outperformed the theoretical FOMs. It is also shown that the MMSE method is very sensitive to small perturbations of the internal filter sensitivities. Real camera images were recorded using the optimally determined filters from both methods. Measured errors provide confirmation of the simulated results.

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“…For both types of instruments, colour variation of the solution has been manipulated to create a signal that represents the measured parameter based on its absorbance behaviour. The use of several optical colour sources requires complex computation and processing task that complicates its development [15], [16]. Monochromatic light source is preferred in some applications with the advantages of a single wavelength implementation to reduce the complexity of processing and its design requirement.…”

Section: Introductionmentioning

confidence: 99%

Optical absorbance of RGB LEDs in pH measurement of colorimetric solution with phenol red reagent

Dali

Azam

Rahman

et al. 2022

IJEECS

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The use of red, green, and blue ( RGB ) light-emitting-diode ( LED ) is a new trend in monochromatic colorimetric sensing due to cost-effective implementation. However, the application of RGB LED in pH measurement depends on the performance of the LED colour towards the colorimetric solution of interest, hence, needs to be evaluated. This work evaluated the performance of RGB LED for pH measurement system based on colorimetric approach using phenol red as a reagent. The main objective was to identify the LED colour with the best performance in terms of signal response and a bsorbance behavior. In this work, LED and photodiode were used as optical components and NI USB DAQ with LabView as the processing software. Four samples with known pH values were prepared and tested to obtain the voltage and absorbance behavior of each LED colour. Among all, the blue LED with wavelength ranged between 450 - 495 nm showed the best sensing behavior based on its linearity and error. Both voltage response and absorbance produced linear correlation with R 2=0.883 and R 2=0.9803, respectively. The significant finding from this study is useful in selecting the best RGB LED that is suitable for colorimetric pH measurement with phenol red as its colorimetric reagent.

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Improving Color Accuracy of Colorimetric Sensors

Cited by 8 publications

References 8 publications

Quantifying the color palettes of Naghsh‐e Jahan Square in Isfahan

Quantifying the color palettes of Naghsh‐e Jahan Square in Isfahan

Determination and use of external color filter for improved camera colorimetry

Optical absorbance of RGB LEDs in pH measurement of colorimetric solution with phenol red reagent

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