Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：ACM Digital Library  

DOI： 10.1145/3582700.3582707

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Association for Computing Machinery  

DOI： 10.1145/3574131.3574441

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer-Verlag  

DOI： 10.1007/s00371-022-02549-4

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE  

Several image recoloring methods have been proposed to compensate for the loss of contrast caused by color vision deficiency (CVD). However, these methods only work for dichromacy (a case in which one of the three types of cone cells loses its function completely), while the majority of CVD is anomalous trichromacy (another case in which one of the three types of cone cells partially loses its function). In this paper, a novel degree-adaptable recoloring algorithm is presented, which recolors images by minimizing an objective function constrained by contrast enhancement and naturalness preservation. To assess the effectiveness of the proposed method, a quantitative evaluation using common metrics and subjective studies involving 14 volunteers with varying degrees of CVD are conducted. The results of the evaluation experiment show that the proposed personalized recoloring method outperforms the state-of-the-art methods, achieving desirable contrast enhancement adapted to different degrees of CVD while preserving naturalness as much as possible.

DOI： 10.1109/TMM.2021.3070108

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer-Verlag  

People with color vision deficiency (CVD) have a reduced capability to discriminate different colors. This impairment can cause inconveniences in the individuals’ daily lives and may even expose them to dangerous situations, such as failing to read traffic signals. CVD affects approximately 200 million people worldwide. In order to compensate for CVD, a significant number of image recoloring studies have been proposed. In this survey, we briefly review the representative existing recoloring methods and categorize them according to their methodological characteristics. Concurrently, we summarize the evaluation metrics, both subjective and quantitative, introduced in the existing studies and compare the state-of-the-art studies using the experimental evaluation results with the quantitative metrics.

DOI： 10.1007/s00371-021-02240-0

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

To enhance the visual details in perception of people with colour vision deficiency (CVD), some methods have been developed to enhance colour contrast. Recently, researchers realized the importance of preserving naturalness in the processed images to avoid decreasing the quality of vision (QOV) and state-of-the-art image recolouring methods succeeded in realising both contrast enhancement and naturalness preservation by utilising optimisation model. However, the high computational cost of these methods prevents their wide application in daily lives. Moreover, these methods cannot automatically resolve the trade-off between contrast enhancement and naturalness preservation. This paper proposes Optimized Dichromacy Projection (ODP) as a novel high-speed image recolouring technique for dichromacy compensation. ODP achieves both contrast enhancement and naturalness preservation by computing an optimized projection from the colour gamut of normal vision to the colour gamut of dichromacy. Evaluation experiments show that the proposed method can generate images of qualities competitive to the state-of-the-art methods while drastically improving computation time.

DOI： 10.1016/j.cag.2021.04.027

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer-Verlag  

Metamorphopsia patients experience distortions in their views. The number of metamorphopsia patients is arising with the increase in the elderly population. For early detection of metamorphopsia, examination approaches have been proposed. However, none of the existing methods can be employed to precisely assess the perceptions of patients. We propose LineM as a novel method to precisely measure the distorted views of metamorphopsia patients based on interactive line manipulation task involving the patients. To explore the potential of LineM, a case study which uses the measured results from LineM to visualize the distorted views of metamorphopsia patients is presented. Furthermore, a novel technique for compensating the distorted views of individual metamorphopsia patients using the results from LineM is also presented. Considering that elderly individuals account for the majority of metamorphopsia patients, an intuitive and user-friendly prototype system has been implemented. The effectiveness and usability of LineM and the compensation method were demonstrated via a qualitative and subjective experiment that involved metamorphopsia patients and elderly participants.

DOI： 10.1007/s00371-021-02091-9

Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI  

About 250 million people in the world suffer from color vision deficiency (CVD). Contact lenses and glasses with a color filter are available to partially improve the vision of people with CVD. Tinted glasses uniformly change the colors in a user’s field of view (FoV), which can improve the contrast of certain colors while making others hard to identify. On the other hand, an optical see-through head-mounted display (OST-HMD) provides a new alternative by applying a controllable overlay to a user’s FoV. The method of color calibration for people with CVD, such as the Daltonization process, needs to make the calibrated color darker, which has not yet been featured on recent commercial OST-HMDs. We propose a new approach to realize light subtraction on OST-HMDs using a transmissive LCD panel, a prototype system, named ALCC-glasses, to validate and demonstrate the new arriving light chroma controllable augmented reality technology for CVD compensation.

DOI： 10.3390/app10072381

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

More than 100 million individuals around the world suffer from color vision deficiency (CVD). Image recoloring algorithms have been proposed to compensate for CVD. This study has proposed a new recoloring algorithm to make up shortages of contrast enhancement and naturalness preservation of the state-of-the-art methods. The recoloring task is formulated as an optimization problem that is solved by using the colors in a simulated CVD color space to maximize contrast and to preserve the original color as much as possible. In addition, the dominant colors are extracted for recoloring. They are then propagated to the whole image so that the optimization problem could be solved at a reasonable cost independent of the image size. In the quantitative evaluation, the results of the proposed method are competitive with those of the best existing method. The evaluation involving subjects with CVD demonstrates that the proposed method outperforms the state-of-the-art method in preserving both the information and the naturalness of images.

DOI： 10.1016/j.image.2019.04.004

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer-Verlag  

Color vision deficiency (CVD) is caused by anomalies in the cone cells of the human retina. It affects approximately 200 million individuals throughout the world. Although previous studies have proposed compensation methods, contrast and naturalness preservation have not been adequately and simultaneously addressed in the state-of-the-art studies. This paper focuses on red–green dichromats’ compensation and proposes a recoloring algorithm that combines contrast enhancement and naturalness preservation in a unified optimization model. In this implementation, representative color extraction and edit propagation methods are introduced to maintain global and local information in the recolored image. The quantitative evaluation results showed that the proposed method is competitive with state-of-the-art methods. A subjective experiment was also conducted and the evaluation results revealed that the proposed method obtained the best scores in preserving both naturalness and information for individuals with severe red–green CVD.

DOI： 10.1007/s00371-019-01689-4

Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation(general)  

Venue：オンライン  

二色覚は色覚障がいの一種で，人間の色覚空間において，色のコントラストを低下させる．既存研究では，本来の画像の自然さを保存しながら，二色覚によるコントラスト損失を補償するための色変換技術を提案した．しかし，最先端の既存手法において，自然さ保存及びコントラスト強調の重みの制御はユーザに任されていて，計算コストも高い故，日常生活上での使用にも制限されるという問題が存在している．本研究では，二色覚を補償するための自然さ保存とコントラスト強調の重みが自動的に制御できる高速の色変換アルゴリズムを提案する．また，定量的評価及び主観的評価実験を行い，提案手法が計算コストを大幅に削減しながら，最先端の既存手法と同等品質の補償画像を生成できることを示している．

Event date： 2020.9

Language：English   Presentation type：Poster presentation  

Venue：Caen, France  

People with color vision deficiency (CVD) may have difficulty in discriminating colors. To improve their color perception, several compensation methods have been proposed which considered naturalness maintenance and contrast emphasis. All these methods are based on the simulation model of severe CVD and hence it is not clear whether are also effective for people with light CVD. In this paper, we conduct subjective study to evaluate the effectiveness of these methods for people with varying degrees of CVD.

Event date： 2019.10

Language：Japanese   Presentation type：Poster presentation  

Venue：ベルクラシック甲府  

Event date： 2019.6

Language：Japanese   Presentation type：Oral presentation(general)  

Venue：早稲田大学国際会議場 1階 井深大ホール  

世界中に一億以上の人がそれぞれに異なるレベルの色覚障がいを持っている．色覚障がいによるコントラストロスを補償するために, コントラスト強調と自然さ保存の両方を考慮した支援画像を作る手法がいくつか提案されている．しかし, ほとんどの既存技術は一色が完全に知覚できない二色覚者を対象としている．本研究は障がい者それぞれの障がいの度合に合わせて最適な変換を行う新しい技術を提案する．シミュレーション画像を用いた定量評価と被験者によるパイロットテストにより, 生成された支援画像は元画像のコントラストおよび自然さを保存できることを示した．

Event date： 2019.5

Language：Japanese   Presentation type：Media report,etc.  

Event date： 2018.6

Language：Japanese   Presentation type：Oral presentation(general)  

Venue：山形テルサ 3階 アプローズ  

世界中に一億人以上が異なるレベルの色覚障がいをもっている．近年，ディジタル機器の普及により，色覚補償のための画像処理技術が注目されている．本研究では，既存手法におけるコントラスト強調と自然さ保存が両立できていないという問題に着目し，自然さとコントラストの両方の保存を目的関数とする最適処理に基づく新しい色変換方法を提案した．画像内の主要な色のみに変換を適用し，Edit Propagationにより結果を画像全体に伝搬させることにより最適化処理の高速化を実現した．シミュレーション画像を用いた定量的評価と被験者による主観的な評価実験において提案手法の優位性を確認することができた．