Takahiko Horiuchi

Takahiko Horiuchi

Chiba University

H-index: 23

Asia-Japan

About Takahiko Horiuchi

Takahiko Horiuchi, With an exceptional h-index of 23 and a recent h-index of 12 (since 2020), a distinguished researcher at Chiba University, specializes in the field of Color Engineering, Digital Image Processing, Visual Information Processing, Shitsukan Analysis, Experimental Psychology.

His recent articles reflect a diverse array of research interests and contributions to the field:

High Dynamic Range Image Reconstruction from Saturated Images of Metallic Objects

Automatic MTF Conversion between Different Characteristics Caused by Imaging Devices

Experimental Study on Reducing Wavelength Dependency of Spatial Resolution Characteristics of a Digital Camera by MTF Correction

Effect of Chromatic Lighting on Emotional Change in the Observation of Affective Pictures

Naturalness Perception of 2.5 D Prints: Elevation and Size of Prints Relation

Prediction model for perceptual gloss by physical measurement of flat objects

Effects of ipRGC on Color Perception based on Display-Based Color-Matching Task

Evaluating the Influence of ipRGCs on Color Discrimination

Takahiko Horiuchi Information

University

Chiba University

Position

Professor Chair Department of Imaging Sciences

Citations(all)

2178

Citations(since 2020)

619

Cited By

1680

hIndex(all)

23

hIndex(since 2020)

12

i10Index(all)

61

i10Index(since 2020)

16

Email

University Profile Page

Chiba University

Takahiko Horiuchi Skills & Research Interests

Color Engineering

Digital Image Processing

Visual Information Processing

Shitsukan Analysis

Experimental Psychology

Top articles of Takahiko Horiuchi

High Dynamic Range Image Reconstruction from Saturated Images of Metallic Objects

Authors

Shoji Tominaga,Takahiko Horiuchi

Journal

Journal of Imaging

Published Date

2024/4/15

This study considers a method for reconstructing a high dynamic range (HDR) original image from a single saturated low dynamic range (LDR) image of metallic objects. A deep neural network approach was adopted for the direct mapping of an 8-bit LDR image to HDR. An HDR image database was first constructed using a large number of various metallic objects with different shapes. Each captured HDR image was clipped to create a set of 8-bit LDR images. All pairs of HDR and LDR images were used to train and test the network. Subsequently, a convolutional neural network (CNN) was designed in the form of a deep U-Net-like architecture. The network consisted of an encoder, a decoder, and a skip connection to maintain high image resolution. The CNN algorithm was constructed using the learning functions in MATLAB. The entire network consisted of 32 layers and 85,900 learnable parameters. The performance of the proposed method was examined in experiments using a test image set. The proposed method was also compared with other methods and confirmed to be significantly superior in terms of reconstruction accuracy, histogram fitting, and psychological evaluation.

Automatic MTF Conversion between Different Characteristics Caused by Imaging Devices

Authors

Midori Tanaka,Tsubasa Ando,Takahiko Horiuchi

Journal

Journal of Imaging

Published Date

2024/2/17

Depending on various design conditions, including optics and circuit design, the image-forming characteristics of the modulated transfer function (MTF), which affect the spatial resolution of a digital image, may vary among image channels within or between imaging devices. In this study, we propose a method for automatically converting the MTF to the target MTF, focusing on adjusting the MTF characteristics that affect the signals of different image channels within and between different image devices. The experimental results of MTF conversion using the proposed method for multiple image channels with different MTF characteristics indicated that the proposed method could produce sharper images by moving the source MTF of each channel closer to a target MTF with a higher MTF value. This study is expected to contribute to technological advancements in various imaging devices as follows: (1) Even if the imaging characteristics of the hardware are unknown, the MTF can be converted to the target MTF using the image after it is captured. (2) As any MTF can be converted into a target, image simulation for conversion to a different MTF is possible. (3) It is possible to generate high-definition images, thereby meeting the requirements of various industrial and research fields in which high-definition images are required.

Experimental Study on Reducing Wavelength Dependency of Spatial Resolution Characteristics of a Digital Camera by MTF Correction

Authors

Tsubasa Ando,Midori Tanaka,Takahiko Horiuchi

Journal

Electronic Imaging

Published Date

2024/1/21

In digital cameras, the wavelength dependency of images captured through lenses and filters affects the spatial resolution characteristics of the images, which adversely impacts image quality. Previously, lens design and image processing techniques have been considered to address the aforementioned problem. Although aberrations could be improved, it was difficult to completely analyze the wavelength dependency of resolution characteristics. This study aims to reduce the wavelength dependency of the spatial resolution of digital cameras. Edge-based modulation transfer function (MTF) measurements using a 2D spectroradiometer were used to obtain wavelength-specific MTFs and quantitively reveal the wavelength dependency of the spatial resolution characteristics. Moreover, we experimentally confirmed that adjusting the MTFs of the CIEXYZ images obtained by combining spectral images to be closer reduces the difference in spatial resolution among color images while minimizing the color change before and after the adjustment.

Effect of Chromatic Lighting on Emotional Change in the Observation of Affective Pictures

Authors

Takahiko Horiuchi,Yuka Matsumoto,Midori Tanaka

Journal

Psychology

Published Date

2023/3/7

The purpose of this study was to analyze the effect of chromatic lighting on the transition from the current emotional state to the desired emotional state. Most previous studies on color and emotion have analyzed the input-output relationship based on one-to-one correspondence between color and emotion under neutral emotion. In this study, we analyzed the relationship between the type of emotion and the lighting color and showed that the transition of emotion can change depending on the current emotional state even under the same lighting color. To improve the stability of experiments, the authors modified the emotion elicitation and analysis methods and compared the findings to our previous studies. We experimentally examined the effects of chromatic lighting on emotions induced by the International Affective Picture System (IAPS) using heart rate variability indices. The results suggest that there are chromatic illuminants that are effective in promoting or suppressing positive and negative emotions. In particular, the results of the heart rate data analysis were more stable and reliable for the chromatic illumination that was effective in promoting and suppressing negative emotions (investigated in the negative impression images) compared to the positive impression group.

Naturalness Perception of 2.5 D Prints: Elevation and Size of Prints Relation

Authors

Altynay Kadyrova,Marius Pedersen,Stephen Westland,Clemens Weijkamp,Takahiko Horiuchi

Journal

London Imaging Meeting

Published Date

2023/6/29

Naturalness is a complex concept and a number of parameters might impact naturalness perception. In this work, we addressed how the combination of different elevation levels and size of prints impacts naturalness perception of 2.5D prints. The results of a subjective ranking experiment showed that observers perceived 2.5D prints as more natural at higher elevation with larger size of print. Moreover, we observed that elevation seems to be a more dominant parameter than size of the print for observers when evaluating naturalness.

Prediction model for perceptual gloss by physical measurement of flat objects

Authors

M Tanaka,S Amari,T Horiuchi

Journal

Lighting Research & Technology

Published Date

2023/6

Although a physical gloss exists as a physically measurable index, people can also perceive a perceptual gloss on object surfaces. However, the physical gloss does not always match the perceptual gloss. Because the physical gloss is calculated based only on the specular gloss and does not reflect other physical features that affect the perceptual gloss. Thus, we analysed the relationships between physical features and perceptual gloss by measuring many physical properties of object surfaces, including their physical gloss. We prepared 127 flat objects comprising three materials: paper, resin and metal plating. The perceptual gloss was visually evaluated for observation angles of 20°, 60° and 85° using a magnitude estimation method. Multiple measurements were conducted to obtain physical features such as the gloss unit (GU), haze, distinctness of image and high dynamic range luminance. We then …

Effects of ipRGC on Color Perception based on Display-Based Color-Matching Task

Authors

Kyosuke Ota,Kota Akiba,Midori Tanaka,Takahiko Horiuchi

Journal

Proceedings http://ceur-ws. org ISSN

Published Date

2022

Intrinsically photosensitive retinal ganglion cells (ipRGCs) affect pupillary light reflex and circadian rhythm regulation. Recent studies have reported that they affect visual perception, particularly brightness perception, and their effect on color perception has also been gradually reported. In this study, we performed a color-matching task on a display device to verify the effect of ipRGC on color perception. Over a year, one participant performed 310 color matching sessions, day and night, by central and peripheral vision. Three blue colors with high ipRGC absorption and three red colors with low ipRGC absorption were used in one session. The color matching results suggest that non-image-forming and image-forming functions interact with col-or perception. We built a regression model in which ipRGC acts on the LMS. We found that the models constructed for each hue explained the experimental results well.

Evaluating the Influence of ipRGCs on Color Discrimination

Authors

Masaya Ohtsu,Akihiro Kurata,Keita Hirai,Midori Tanaka,Takahiko Horiuchi

Journal

Journal of Imaging

Published Date

2022/5/28

To investigate the influence of intrinsically photosensitive retinal ganglion cells (ipRGCs) on color discrimination, it is necessary to create two metameric light stimuli (metameric ipRGC stimuli) with the same amount of cone and rod stimulation, but different amounts of ipRGC stimulation. However, since the spectral sensitivity functions of cones and rods overlap with those of ipRGCs in a wavelength band, it has been difficult to independently control the amount of stimulation of ipRGCs only. In this study, we first propose a method for calculating metameric ipRGC stimulation based on the orthogonal basis functions of human photoreceptor cells. Then, we clarify the controllable range of metameric ipRGC stimulation within a color gamut. Finally, to investigate the color discrimination by metameric ipRGC stimuli, we conduct subjective evaluation experiments on 24 chromaticity coordinates using a multispectral projector. The results reveal a correlation between differences in the amount of ipRGC stimulation and differences in color appearance, indicating that ipRGCs may influence color discrimination.

Layered Perceptual Modeling Using Structural Equation Modeling: Exploring Structure with Genetic Algorithm

Authors

Shuhei Watanabe,Takahiko Horiuchi

Published Date

2022/10/9

To differentiate from competitors, it has become increasingly important to design products based on the “Kansei value,” which impresses and inspires consumers. However, the perceptual indices of products are generally designed qualitatively, which is not only time-consuming but also costly. Therefore, in recent years, studies have been conducted to discuss the relationship between some perceptions by applying multivariate analysis and machine learning to the adjectives related to perception and affective response. Nonetheless, determining the structure that expresses the relationship of the adjectives is obtained by trial and error, based on the hypothesis of the researchers. Therefore, we aimed to investigate a method for mechanically exploring some semi-optimal structures without a hypothesis of the model structure by applying a genetic algorithm to the construction of adjective relationships using structural …

Effect of Pixel Aperture Ratio on Subjective Spatial Resolution

Authors

Nakamura Keita,Tanaka Midori,Horiuchi Takahiko,Masaoka Kenichiro

Journal

Proceedings of the International Display Workshops

Published Date

2022/12/14

Effect of Pixel Aperture Ratio on Subjective Spatial Resolution | CiNii Research CiNii 国立 情報学研究所 学術情報ナビゲータ[サイニィ] 詳細へ移動 検索フォームへ移動 論文・データをさがす 大学図書館の本をさがす 日本の博士論文をさがす English 検索 タイトル 人物/団体名 所属機関 ISSN DOI 期間 ~ 本文リンク 本文リンクあり データソース JaLC IRDB Crossref DataCite NDL NDL-Digital RUDA JDCat NINJAL CiNii Articles CiNii Books CiNii Dissertations DBpedia Nikkei BP KAKEN Integbio MDR PubMed LSDB Archive 公共データカタログ ムーンショット型研究 開発事業 すべて 研究データ 論文 本 博士論文 プロジェクト Effect of Pixel Aperture Ratio on Subjective Spatial Resolution DOI Nakamura Keita Tanaka Midori Horiuchi Takahiko Masaoka Kenichiro 収録刊行物 Proceedings of the International Display Workshops Proceedings of the International Display Workshops 671-, 2022-12-14 一般社団法人ディスプレイ国際ワークショップ …

Slippage-and load-induced changes in the crystalline orientation of oligo (3-methoxythiophene) powder to develop a gold-tone luster

Authors

Satoya Sugiura,Terumasa Mitogawa,Kota Saito,Rihito Tamura,Satoru Tsukada,Takahiko Horiuchi,Katsuyoshi Hoshino

Journal

RSC advances

Published Date

2022

The achievement of molecular orientation control by rubbing and pressing poly(3-alkylthiophene)s is a powerful technique to improve the performance of organic electronic devices. We report here that the rubbing and pressing of blackish-brown 3-methoxythiophene oligomer powders yield layer and tablet samples with gold tones, respectively. Specular reflectivity, colorimetric, and X-ray diffraction measurements reveal that this gold tone is caused by an increase in the ratio of edge-on lamellar crystallites to face-on ones, which is promoted by rubbing/pressing. In contrast to the 3-alkylthiophene polymer, which develops a dominant face-on lamellar structure, rubbing of the 3-methoxythiophene oligomer increases the relative amount of edge-on lamellar crystallites to face-on lamellar ones. Furthermore, gold tone development in the tablet samples is limited to the near-surface area, despite the fact that pressure is …

構造方程式モデリングを用いた質感知覚モデルの構築

Authors

渡辺修平, 堀内隆彦

Journal

IEICE Conferences Archives

Published Date

2022/3/1

産業界では,競合との差別化を図るため感性価値に基づいた製品開発が重要となっている.しかし,製品の質感や情動的な項目の設計は定性的になされており,多くの時間とコストを費やしている.この問題に対するアプローチとして,我々は素材に対して知覚する質感や情動を定量化し,それらの関係性を明らかする研究を行っている.質感や情動を定量化できれば,製品開発の高効率化だけでなく,消費者に狙い通りの知覚を与えられる.本稿では,被験者に質感や情動に関する評価語を様々な素材サンプルに対して評価させ,その結果を用いて,SEMによる質感知覚モデルの構築を検討した.その結果,予測精度が高く意味的にも解釈可能なモデルを構築できた.

Simple Color Calibration Method by Projection onto Retroreflective Materials

Authors

Yusuke Nakamura,Takahiko Horiuchi

Journal

Journal of Imaging

Published Date

2022/9/3

Retroreflective materials have the property of directional reflection, reflecting light strongly in the direction of the light source, and have been used for road traffic signs. In recent years, retroreflective materials have been used in entertainment and industrial technologies, in combination with projection mapping technology. In general, color calibration is important when projectors are used to control reflected colors. In this study, we investigated a simple color calibration method for retroreflective materials with a 3D shape under the condition that they are observed in the same direction as the light source. Three types of retroreflective materials with different reflective properties were used. First, to measure the reflective properties of each reflective material, the reflective material was fixed to a flat plate and rotated, while the reflected light was measured in the same direction as the light source. It was then confirmed that the reflected light intensity varied smoothly with angular change, and appropriate measurement angles were investigated based on the AIC criterion, aiming to interpolate the reflectance characteristics from a small number of measurement angles. Color calibration was performed based on the reflectance characteristics obtained from the derived measurement angles, and the experiments showed that good color calibration was possible with fewer measurements.

Metaheuristic optimization for improving weed detection in wheat images captured by drones

Authors

El-Sayed M El-Kenawy,Nima Khodadadi,Seyedali Mirjalili,Tatiana Makarovskikh,Mostafa Abotaleb,Faten Khalid Karim,Hend K Alkahtani,Abdelaziz A Abdelhamid,Marwa M Eid,Takahiko Horiuchi,Abdelhameed Ibrahim,Doaa Sami Khafaga

Journal

Mathematics

Published Date

2022/11/23

Background and aim Machine learning methods are examined by many researchers to identify weeds in crop images captured by drones. However, metaheuristic optimization is rarely used in optimizing the machine learning models used in weed classification. Therefore, this research targets developing a new optimization algorithm that can be used to optimize machine learning models and ensemble models to boost the classification accuracy of weed images. Methodology This work proposes a new approach for classifying weed and wheat images captured by a sprayer drone. The proposed approach is based on a voting classifier that consists of three base models, namely, neural networks (NNs), support vector machines (SVMs), and K-nearest neighbors (KNN). This voting classifier is optimized using a new optimization algorithm composed of a hybrid of sine cosine and grey wolf optimizers. The features used in training the voting classifier are extracted based on AlexNet through transfer learning. The significant features are selected from the extracted features using a new feature selection algorithm. Results The accuracy, precision, recall, false positive rate, and kappa coefficient were employed to assess the performance of the proposed voting classifier. In addition, a statistical analysis is performed using the one-way analysis of variance (ANOVA), and Wilcoxon signed-rank tests to measure the stability and significance of the proposed approach. On the other hand, a sensitivity analysis is performed to study the behavior of the parameters of the proposed approach in achieving the recorded results. Experimental results confirmed the …

Glossiness Index of Objects in Halftone Color Images Based on Structure and Appearance Distortion

Authors

Donghui Li,Midori Tanaka,Takahiko Horiuchi

Journal

Journal of Imaging

Published Date

2022/2/27

This paper proposes an objective glossiness index for objects in halftone color images. In the proposed index, we consider the characteristics of the human visual system (HVS) and associate the image’s structure distortion and statistical information. According to the difference in the number of strategies adopted by the HVS in judging the difference between images, it is divided into single and multi-strategy modeling. In this study, we advocate multiple strategies to determine glossy or non-glossy quality. We assumed that HVS used different visual mechanisms to evaluate glossy and non-glossy objects. For non-glossy images, the image structure dominated, so the HVS tried to use structural information to judge distortion (a strategy based on structural distortion detection). For glossy images, the glossy appearance dominated; thus, the HVS tried to search for the glossiness difference (an appearance-based strategy). Herein, we present an index for glossiness assessment that attempts to explicitly model the structural dissimilarity and appearance distortion. We used the contrast sensitivity function to account for the mechanism of halftone images when viewed by the human eye. We estimated the structure distortion for the first strategy by using local luminance and contrast masking; meanwhile, local statistics changing in the spatial frequency components for skewness and standard deviation were used to estimate the appearance distortion for the second strategy. Experimental results showed that these two mixed-distortion measurement strategies performed well in consistency with the subjective ratings of glossiness in halftone color images.

Bumpy Appearance Editing of Object Surfaces in Digital Images

Authors

Yusuke Manabe,Midori Tanaka,Takahiko Horiuchi

Journal

Color and Imaging Conference

Published Date

2022/9/1

Abstract Objects in nature have diverse appearances, and appearance is one of the elements constituting the unique visual aspect of an object. However, previous studies have shown that when an object is represented as a digital image, its appearance can change compared to the real object depending on the material. In this study, the focus was on the “bumpiness” of the object surface, whereby a method was proposed to edit the bumpiness of the object in the image. First, the statistics obtained from images were analyzed in relation to the sensibility value of the bumpiness perceived by humans. Since the statistics on the original image could not fully explain the perception of bumpiness, analyses were conducted on multiscale images. The results suggested that the mean, standard deviation, and top, defined as the average of the luminance values within the top 10 [percentile], were highly influential as cues for bumpiness perception. The results also indicated that the components in the range of 5–65 [cycles per image-width] were highly influential. Based on these analysis results, a method is proposed to edit bumpiness perception by modulating components in the low and medium frequency bands. The effectiveness of the proposed method is demonstrated by image modulation experiments on objects of various materials.

ディジタル画像で表現された物体表面の凹凸感編集方法

Authors

真鍋裕亮, 田中緑, 堀内隆彦

Journal

電気学会研究会資料. OQD= The papers of technical meeting on optical and quantum devices, IEE Japan/光・量子デバイス研究会 [編]

Published Date

2022/10/28

ヒカリ・リョウシ デバイス ケンキュウカイ・ガゾウ ギジュツ, VR/AR, ヒューマンファクター カンレン, ソノタ イッパン

Effects of Display Modulation Transfer Function with Different Subpixel Layouts on Subjective Spatial Resolution

Authors

Tsubasa Ando,Midori Tanaka,Takahiko Horiuchi,Kenichiro Masaoka

Journal

Proceedings http://ceur-ws. org ISSN

Published Date

2022

Although a typical display consists of red-green-blue (RGB) subpixels, displays with various subpixel layouts have been used owing to their various advantages such as luminous efficiency. The purpose of this study is to verify the effects of display MTF on subjective spatial resolution by creating new subpixel layouts. We designed BRGRB and BRGRB525 subpixel layouts with slightly higher and much higher MTF than RGB subpixel layouts, and conducted visual evaluation experiments with RGB, PenTile RGBG and the two new subpixel layouts at 20 and 30 cycles per degree. It was verified that subjective spatial resolution generally follows the large and small relationship of display MTF. Additional experiments showed that the integral of the product of the contrast sensitivity function and MTF was highly correlated with the subjective spatial resolution.

Preliminary Evidence for the Effect of Circadian Rhythms on Color Perception

Authors

Kyosuke Ota,Midori Tanaka,Takahiko Horiuchi

Journal

International Colour Association (AIC) Conference 2022

Published Date

2022/6/13

Intrinsically photosensitive retinal ganglion cells (ipRGCs) affect the pupillary light reflex and regulation of circadian rhythms. ipRGCs have also recently been shown to affect visual perception, especially brightness perception, and reports are gradually accumulating to affect color perception. The purpose of this study was to verify the effects of ipRGCs on color perception through the repeated performance of color matching on the same display screen at different times of day. We performed color matching a total of 290 times over a period of nine months. The color matching results showed that central vision exhibited lower color discrimination ability than peripheral vision. Furthermore, significance tests revealed that the color perception characteristics between central and peripheral vision differed between day and night, indicating that M1 ipRGCs, which affect non-image-forming functions, and non-M1 ipRGCs, which affect image-forming functions, may interactively affect color perception.

Bumpy Appearance Editing Method of Object Surfaces in Digital Images

Authors

Yusuke Manabe,Midori Tanaka,Takahiko Horiuchi

Journal

IEICE Technical Report; IEICE Tech. Rep.

Published Date

2022/10/21

(in English) Appearance is one of the elements constituting the unique visual aspect of an object. However, previous studies have shown that when an object is represented as a digital image, its appearance can change compared to the real object depending on the material. Thus, a method to edit the appearance in images is required. In this study, we focus on the “bumpiness” of the object surface, whereby a method is proposed a method to edit the bumpiness of the object in the image. First, we analyzed the relationship between statistics obtained from images and the sensibility values of the bumpiness perceived by humans. The results suggested that the mean, standard deviation, and the average of the luminance values within the top 10 percentile were highly influential as cues for the bumpiness perception. The results also indicated that the components in the low and medium frequency bands were highly …

See List of Professors in Takahiko Horiuchi University(Chiba University)

Takahiko Horiuchi FAQs

What is Takahiko Horiuchi's h-index at Chiba University?

The h-index of Takahiko Horiuchi has been 12 since 2020 and 23 in total.

What are Takahiko Horiuchi's top articles?

The articles with the titles of

High Dynamic Range Image Reconstruction from Saturated Images of Metallic Objects

Automatic MTF Conversion between Different Characteristics Caused by Imaging Devices

Experimental Study on Reducing Wavelength Dependency of Spatial Resolution Characteristics of a Digital Camera by MTF Correction

Effect of Chromatic Lighting on Emotional Change in the Observation of Affective Pictures

Naturalness Perception of 2.5 D Prints: Elevation and Size of Prints Relation

Prediction model for perceptual gloss by physical measurement of flat objects

Effects of ipRGC on Color Perception based on Display-Based Color-Matching Task

Evaluating the Influence of ipRGCs on Color Discrimination

...

are the top articles of Takahiko Horiuchi at Chiba University.

What are Takahiko Horiuchi's research interests?

The research interests of Takahiko Horiuchi are: Color Engineering, Digital Image Processing, Visual Information Processing, Shitsukan Analysis, Experimental Psychology

What is Takahiko Horiuchi's total number of citations?

Takahiko Horiuchi has 2,178 citations in total.

What are the co-authors of Takahiko Horiuchi?

The co-authors of Takahiko Horiuchi are Aboul Ella Hassanien Ali, Abdelhameed Ibrahim, Hitoshi Kiya, Tarek Gaber, Javier Hernández-Andrés, Khairul Munadi.

    Co-Authors

    H-index: 87
    Aboul Ella Hassanien Ali

    Aboul Ella Hassanien Ali

    Cairo University

    H-index: 61
    Abdelhameed Ibrahim

    Abdelhameed Ibrahim

    Mansoura University

    H-index: 40
    Hitoshi Kiya

    Hitoshi Kiya

    Tokyo Metropolitan University

    H-index: 30
    Tarek Gaber

    Tarek Gaber

    University of Salford

    H-index: 24
    Javier Hernández-Andrés

    Javier Hernández-Andrés

    Universidad de Granada

    H-index: 20
    Khairul Munadi

    Khairul Munadi

    Universitas Syiah Kuala

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