Color correction of electrowetting electronic paper based on color space transformation

Mao Wenjie; Lin Shanling; Lin Jianpu; Mei Ting; Wang Tingyu; Cai Bipeng; Zhang Jianhao; Lin Zhixian

doi:10.12086/oee.2025.240226

Article navigation > Opto-Electronic Engineering > 2025 Vol. 52 > No. 2 > 240226

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Mao W J, Lin S L, Lin J P, et al. Color correction of electrowetting electronic paper based on color space transformation[J]. Opto-Electron Eng, 2025, 52(2): 240226. doi: 10.12086/oee.2025.240226

Citation:

Mao W J, Lin S L, Lin J P, et al. Color correction of electrowetting electronic paper based on color space transformation[J]. Opto-Electron Eng, 2025, 52(2): 240226. doi: 10.12086/oee.2025.240226

Color correction of electrowetting electronic paper based on color space transformation

1.
School of Advanced Manufacturing, Fuzhou University, Quanzhou, Fujian 362252, China
2.
Fujian Science and Technology Innovation Laboratory for Photoelectric Information , Fuzhou, Fujian 350116, China

Fund Project: National Key R&D Program of China (2021YFB3600603)

More Information

^*Corresponding author: lzx2005000@163.com
CSTR: 32245.14.oee.2025.240226

Received Date 24 September 2024

Revised Date 04 January 2025

Accepted Date 06 January 2025

Published Date 28 February 2025

Abstract

Abstract

Electrowetting electronic paper employs a subtractive color mixing system for color display, which results in a smaller color gamut and potential color distortion. Additionally, it relies on ambient light's diffuse reflection, leading to insufficient brightness. To address these issues, this paper proposes a color space transformation and image adaptive enhancement algorithm for color electrowetting. The algorithm converts the image from the RGB color space to the HSV space, using CLAHE to evenly distribute saturation and improve color performance. The luminance channel is enhanced through guided filtering combined with an improved Retinex algorithm, preserving detail and edge information, and ensuring the electrowetting display maintains realistic visual effects under the same lighting conditions. Experimental results show that the algorithm improves PSNR, SSIM, FSIM, and FSIMc by 19%, 10.8%, 19.19%, and 19.54%, respectively. This algorithm significantly enhances the display performance of electrowetting electronic paper, laying a solid foundation for its commercialization.
- color electrowetting electronic paper /
- color space transformation /
- image enhancement /
- histogram equalization

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References

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Overview

Overview

Electrowetting electronic paper uses a subtractive color-mixing system with three primary inks (cyan, magenta, and yellow), which results in a reduced color gamut and colorimetric distortion. These issues arise from the difference between subtractive color mixing and traditional additive RGB systems. Electrowetting displays also depend on ambient light, but diffuse reflection from the display surface often leads to insufficient brightness. This negatively impacts the display quality and visual clarity, especially in low-light conditions.

To address these issues, a color space conversion and image self-adaptive enhancement algorithm is proposed for electrowetting color displays. The objective is to improve color accuracy, increase brightness, and maintain image clarity while overcoming the challenges posed by the reflective nature of the display. The algorithm converts RGB images into the HSV color space, enabling more effective manipulation of color and brightness components. CLAHE (contrast limited adaptive histogram equalization) is applied to the saturation channel (S channel), redistributing saturation more evenly and avoiding over-saturation in specific hues, resulting in a more balanced and vivid color presentation. The brightness channel (V channel) is enhanced by using an improved Retinex algorithm combined with a guidance filter. This method improves brightness and contrast while preserving details and edges, addressing the issue of insufficient brightness caused by the reflective display surface. The algorithm ensures that the electrowetting display maintains realistic and stable visual performance under different lighting conditions.

Experimental results show significant improvements in image quality, with PSNR of 70.5047 dB and SSIM of 0.8378. FSIM and FSIMc, which are used to measure human visual perception, reach 0.8409 and 0.84, respectively. Compared to the FHRPHS algorithm, the proposed method improves PSNR by 19%, SSIM by 10.8%, and FSIM and FSIMc by 19.19% and 19.54%, respectively. These improvements highlight the effectiveness of the approach in enhancing color performance and image clarity, especially in scenarios with limited color gamut, making it suitable for improving electrowetting electronic paper display quality.