Fumihiko Ichikawa

Inspection of skin hemodynamics with hyperspectral camera

Using hyperspectral imaging techniques, which enable us to simultaneously obtain spatial and wavelength information, we have improved upon the newly developed hyperspectral camera to develop a method of observing changes in skin melanin levels and hemodynamics over time. As an evaluation of this method, we measured the skin diffuse reflectance spectrum of the human middle finger in an experiment of blood flow blockage in the brachial region. The changes in skin hemodynamics observed through this method match the behavior expected based on clinical knowledge, and also show an extremely high correlation with results obtained by the Erythema Index, which is used to make similar calculations from a limited number of wavelengths.

Real-Time Imaging Spectrometry of Tissues for Photodynamic Diagnosis (PDD)

A novel imaging spectrometry was demonstrated which can accurately measure the spectrum of whole surface of tissue instead of a single point. Using this apparatus, we obtained the microscope spectrometry image of the hematoxylin-eosin stained tumorous tissue and normal (muscle and blood vessel) mouse tissue was obtained. From the pseudo RGB images of the spectra, tumorous and normal tissues were observed very clearly. The spectra at arbitrary positions could be taken instantly as well as the transmission and absorption spectra, which normalized to the background spectrum. The spectral intensity distribution images were obtained at selected wavelengths to get the area distribution of the stained tumorous and normal tissue clearly. In our experiments, we obtained clear spectrometry imaging from weakly illuminated objects. It took 30 seconds to measure a static image of a sample. Moreover, this apparatus is suitable for real-time measurements of living tissue if using laser illumination, a high-speed CCD camera, a fiber, an endoscope and photosensitizer. In the near future, this novel technique can be used in tumor photodynamic diagnosis.

Inspection system using still vision for a rotating laser-textured dull roll

A new inspection system measuring micro-craters on a rotating laser textured dull roll surface has been developed. This system provides a video image of the rotating roll surface as a still vision using a stroboscopic light and a rotating mirror, and measures the diameter and the pitch of the micro-craters by an image processing method. The system can measure the pitch and the diameter of the micro-craters in the accuracy within ±10 mm errors when the circumferential speed of the dull roll is lOm/sec.

Real-time imaging spectrometry for microscope

Significant research attention has focused on the photodynamic diagnosis (PDD) technique, which uses imaging spectrometry to analyze the image and spectra. Up to now, the fluorescence spectrum at only one point in the image can be measured by imaging spectrometry, but it is not enough for diagnosis. The problem is how to obtain the relationship between the exact position and its respective spectrum. In this paper, we demonstrated a novel imaging spectrometry, which can accurately measure the whole surface of tissue instead of a single point. Using this apparatus, we measured the microscope spectrometry image of the hematoxylin-eosin stained tumorous tissue of mice. From the pseudo RGB images of the spectra, tumorous tissues were very clear. In this image, the spectra at arbitrary positions could be taken instantly as well as the transmission and absorption band based on the background spectrum. The spectral intensity distribution images were also obtained at selected wavelengths (for example 425 nm, 505 nm, 535 nm, 600 nm) to get the area distribution of the stained tumorous tissue. In our experiments, we obtained clear spectrometry imaging from weakly illuminated objects. It took 30 seconds to measure a static image of a sample. Moreover, this apparatus is suitable for real-time measurements of living tissue if using laser illumination, a high-speed CCD camera, a fiber, an endoscope and photosensitizer. In the near future, this novel technique can be used in tumor photodynamic diagnosis.