Our life has surely become convenient since image media such as a digital camera has developed and spread rapidly. It is true, however, that capability of such image media is nothing like as good as that of the human vision because it is far easy for our vision to capture image information, code the information, and recognize it. The purpose in this project is to crystallize as "technology" the knowledge acquired by the fundamental research of vision science. We are now tackling various topics as follows.
Illuminations using light emitting diode (LED) can change its lighting spectrum freely because of variety of LED’s emission spectrum with narrow band. A method for optimization of lighting spectrum has been designed. In general, there exist several problems, such as the need for spectrum imaging system to measure a reflectance of targets, the differences between the simulation and real LEDs and the need for the time consuming process to design illuminations of LEDs. But, we develop the accurate and effective system for designing spectrum of functional illuminations automatically. As for the demonstration of the proposed system, two illuminant spectra with combination LEDs were designed (For changing colorfulness and changing color-difference). It took less than 60seconds to design the illuminant spectra.
We make lots of decisions using visual information, especially color information.For example, we can infer whether the food quality or went bad from its changing color.In our laboratory, we have investigated wavelength characteristic of the light specific from emphasizing the distance between colors, and have developed the LED lighting equipment.The image above is an example of the lighting equipment that emphasizes color distance between the foods and foreign matter in such a way as to a visual inspection process for foods.We can see that the designed LED light is easier to identify the stone or seed in the foods.
Various substances, such as food, animals and plants have the fluorescence. And it is known that the fluorescence characteristic is peculiar to substances. Therefore, distinction of substances and determine the quantity of them can be performed by observing the fluorescence. Fluorescence excitation matrix is two-dimensional matrices obtained by acquiring the spectrum information while changing the light irradiation (left figure). Our research has been estimated the freshness of spinach using such fluorescence information. Freshness presumption is performed using the fluorescence component of the spinach, and we succeeded in visualization the information (freshness) which cannot be seen by people's eyes (right figure). Now, the monitoring technology of the cleanliness of meat using fluorescence excitation matrix is being developed.
We have achieved for the first time in the world, designing spectrum filter which a person with normal color vision can feel and discover combination of colors that is easy to mix up for a colorblind person in real time. Now, the spectrum filter has been produced commercially as colorblind experience filter, "Varialtor" series. It is widely used in printed matter in private enterprises, governmental agency, in public sign, in textbook and maintenance of school environment, CUD education seminar, etc.
・Good Design Award 2007 [External Link]
The light reflected from the surface of an object contains a range of information about its physical and chemical properties. At this laboratory, we are researching about the technique to achieve such information by enhancing slight spectral difference.
It is well known that washing hands is an important process in order to prevent food poisoning transfer and infection. More than 20,000 people become food poisoned every year, and about 73% of deaths from food poisoning were basically caused by bacteria. In food processing plants and medical institutions, health supervision is crucially important by following very restricted guidance and regulations. However, food poisoning has not decreased in some circumstances despite applying these regulations. Although it is believed that identifying the cause is completely difficult, the aim of this study was to develop a robust method for visualizing human hands to evaluate their cleanliness from dirt and microorganisms using uorescence imaginary technique.
Our research has been estimated the freshness of frozen seafood using such fluorescence information. Estimated the optimal combination of excitation wavelength and fluorescence wavelength using difference of the fluorescence component of the fish surface and we succeeded in visualization the freshness by using the optimal fluorescence component.
・Gamal ElMasry, Naho Nakazawa, Emiko Okazaki, Shigeki Nakauchi (2016). Non-invasive sensing of freshness indices of frozen fish and fillets using pretreated excitation–emission matrices;, Sensors and Actuators B: Chemical, Vol. 228, No. 2, pp. 237-250, 2016. [External Link]
・Gamal ElMasry, Hiroto Nagai, Keisuke Moria, Naho Nakazawa, Mizuki Tsuta, Junichi Sugiyama, Emiko Okazaki, Shigeki Nakauchi (2015). Freshness estimation of intact frozen fish using fluorescence spectroscopy and chemometrics of excitation-emission matrix;, Talanta, Vol. 143, No. 1, pp. 145-156, 2015. [External Link]
Various substances, such as food, animals and plants have the fluorescence. And it is known that the fluorescence characteristic is peculiar to substances. Therefore, distinction of substances and determine the quantity of them can be performed by observing the fluorescence. Excitation Emission Matrix(EEM) has two-dimensional matrices obtained by acquiring the spectrum information while changing the light irradiation (left figure). Our research has been estimated viable bacteria counts on the surface of pork meat using such fluorescence information. Estimated the viable bacteria counts is performed using the fluorescence component of the pork surface, and we succeeded in visualization the information (viable bacteria counts) which cannot be seen by people's eyes (right figure). Now, freshness of meat and fish have been researched using EEM.
・Ken Nishino, Kazuaki Nakamura, Mizuki Tsuta, Masatoshi Yoshimura, Junichi Sugiyama, and Shigeki Nakauchi. “Optimization of excitation–emission band-pass filter for visualization of viable bacteria distribution on the surface of pork meat”, Optics Express, Vol. 21, No. 10, pp. 12579-12591, 2013. [External Link]
Shine Muscat is a grape cultivar that has large yellow-green berries, crisp flesh, and a high sugar content. In a previous research, a color chart to judge the harvest time for Shine Muscat was developed. However, the skin color does not change consistently with the color chart depending on the cultivation environment and the harvest season. In this research, the relationship between the sugar content and spectra was investigated. The results suggest that the sugar content of Shine Muscat can be accurately estimated by absorption spectra in near-infrared region. Moreover, we showed the possibility of the estimation of the sugar content by our prototype device implemented with LEDs and a photodiode.
Sunscreen is often used to defend from ultraviolet ray (UV) which adversely affects skin such as the stain or wrinkle. SPF is used for UV protection ability and it is factor to select the products. SPF for a sunscreen is defined by an in vivo measurement where sunscreens are applied over skins of humans, the applied and unapplied parts are exposed to UV. Therefore it takes long time and imposes a burden on subjects. We propose a method to estimate and visualize SPF of sunscreens by measurement of light reflected by the sunscreens applied over human skins. In order to estimate SPF of sunscreens on skins, we use an SPF estimation model. With the proposed model, we visualized the UV protection ability of sunscreen and variation of UV protection ability by time variation as shown upper figure.
Pearl is one of traditional products in Japan. Quality of pearl is determined by gemologists' visual inspection based on several factors such as size, gloss, richness of interference color and so on. However, it is difficult to evaluate pearl quality by bare eyes alone and a clear criterion for the evaluation is still needed. In collaboration with several organizations involving pearls in Japan, we aim to develop a system that assists pearl quality evaluation by employing gloss and interference color measuring technique. We also aim to develop a method to express pearl quality evaluation result numerically which is based on human's visual mechanisms.
・Hamamatsu Optronics Cluster
・Mie Prefecture Fisheries Research Institute
・Hamamatsu Metrix Co., Ltd.
・Toshihiro Toyota, Shigeki Nakauchi ，“Optical measurement of interference color of pearls and its relation to subjective quality;Journal Optical Review ，Volume 20，Issue 1，2013. [External Link]
We use a foundation cream to make ourself up. The distribution information that means the amount of applied foundation creams is important for the beauty of a result when we apply foundation creams. However, there has never established the technique of image instrumentation of distribution of applied foundation creams. We collaborated with Kanebo Ltd. and developed the non-destructive, quantitative and new measuring technique that enable to measure the distribution of foundation creams. The above image shows "the quantitative measuring system for spatial distribution of foundation cream". Using the designed optical filter, emphasize the difference of spectral characteristics between skin and foundation cream, is enable to visualize a spatial distribution of applied foundation cream as an image. In the future, it is expected to apply this system for counseling, development of new cosmetic technique and development of pharmaceutical preparation.
・Kanebo cosmetics Ltd.
・Ken Nishino， Mutsuko Nakamura，Masayuki Matsumoto，Osamu Tanno，and Shigeki Nakauchi，Optical filter for highlighting spectral features Part I: design and development of the filter for discrimination of human skin with and without an application of cosmetic foundation. Optics Express Vol. 19，Iss. 7，pp. 6020-6030 (2011) [External Link]
・Ken Nishino ，Mutsuko Nakamura，Masayuki Matsumoto，Osamu Tanno，and Shigeki Nakauchi，Optical filter highlighting spectral features Part II: quantitative measurements of cosmetic foundation and assessment of their spatial distributions under realistic facial conditions. Optics Express Vol. 19，Iss. 7，pp. 6031-6041 (2011) [External Link]
In the infrared light which can't be seen with human's eyes, loads of information is kept hidden. With expectation of useful information, we proceed several researches to extract potential information from the infrared light and our research on "Allergic Dermatitis Inspection Using Infrared Spectrum Imaging" is one example. Allergic dermatitis can be classified into several categories and even with dermatologist's experience, diagnosis from skin swelling alone is still difficult. From our research result, we found that classification of urticaria(left, Type I) and contact dermatitis(right, Type IV) is possible with employment of infrared light spectrum imaging technique.
・Hamamatsu University School of Medicine [External Link]
Taste and quality of food is closely involved with its components. Not only the tastes like saltiness and sweetness, organoleptic feel also highly depends on amount and type of components in the food. Since usual food component analysis using chemical methods is required knowledge and skill for analysis. Furthermore, the usual method consumes too much time for getting results and the food sample won't be consumable anymore. Our study, we aim to develop a faster and nondestructive method using spectroscopic analysis. Here, we focus on light absorption characteristic of each component and use it to visualize the component in the food in order to evaluate its quality. The movie above shows the visualized fat content that is the most important in beef quality and oleic acid contained in especially soft, high quality meat using several optical filters images which are specially designed in their transmission property. The sample that contains lots of oleic acid is soft and presented in red, the sample that contains less oleic acid is presented in blue.
・Hamamatsu Optronics Cluster
・Mie Prefecture Fisheries Research Institute
・Sumitomo Electric Industries [External Link]
・Ken-ichi Kobayashi， Yasunori Matsui，Yosuke Maebuchi，Toshihiro Toyota and Shigeki Nakauchi，“Near infrared spectroscopy and hyperspectral imaging for prediction and visualisation of fat and fatty acid content in intact raw beef cuts”，Journal of Near Infrared Spectroscopy，Volume 18，Issue 5，2010. [External Link]
・Ken-ichi Kobayashi, Masaaki Mori, Ken Nishino, Toshihiro Toyota and Shigeki Nakauchi，“Visualisation of fat and fatty acid distribution in beef using a set of filters based on near infrared spectroscopy”，Journal of Near Infrared Spectroscopy，Volume 20，Issue 5，2012. [External Link]