Development of Image Processing System for Fundus Video-Angiography with Non-Stroboscopic Illumination

Now a days in clinical ophthalmology.Fluorescein ocular fundus angiography(FAG)is one of the most important examinations for evaluating chorioretinal circulation。But the FAG has many problems of pharmacological and psychological stress on patients，that means the fluorescent dye is sometimes toxic and about half of examines are suffered from side-effects and also the strong exciting light illumination is very much troublesome for them.So we developed a new system for recording an ocular fundus photography and video-angiographic FAG by incorporing a high-sitive color couge camera。The signal from the camera could be personal computer either directly or from the data stored in a video tape recorder.Using our new system we made it possible to perform continuous and sequential recording of fundus photography without stroboscopic flashes.We could also reduce fluorescent dye to1/2 of the usual dose.In other words。We can put a stress on following features in our systems；1)Reducing the physical and psychological stress on the patients as well as recording continuously on real time2)Extraction of clear image from less distinct record through off-line processing3)Quantitated evaluation of minor differences in the color of the ocular fundus by enhancing either red-，green-，blue-components of the signal and comparison of fus images as seen in color of the color of the ocular fundus by enhancing either red-，green--，blue-components of the signal and comparison of fus images as seen in color to undoges of bullis and freides of through of the hous.

Now a days in clinical ophthalmology. Fluorescein ocular fundus angiography (FAG) is one of the most important examinations for evaluating chorioretinal circulation. But the FAG has many problems of pharmacological and psychological stress on patients, that means the fluorescent dye is sometimes toxic and about half of examines are suffered from side-effects and also the strong exciting light illumination is very much troublesome for them.So we developed a new system for recording an ocular fundus photography and video-angiographic FAG by incorporating a high-sensitive color charge coupled device (CCD) camera into a fundus camera. The signal from the camera could be personal computer either directly or from the data stored in a video tape recorder. Using our new system we made it possible to perform continuous and sequential recording of fundus photography without stroboscopic flashes. We could also reduce fluorescent dye to 1/2 of the usual dose.In other words. We can put a stress on following features in our systems ;1) Reducing the physical and psychological stress on the patients as well as recording continuously on real time 2) Extraction of clear image from less distinct record through off-line processing 3) Quantitated evaluation of minor differences in the color of the ocular fundus by enhancing either red-, greenー, blue-components of the signal and comparison of fundus images as seen in color to angiogram 4) Quantification of the blood flow in large vessels of ocular fundus by subtracting two successive images.These features appeared to be of values in analyzing retinal circulation both in normal and pathological fundus in the future.