| 摘要 |
<p>PROBLEM TO BE SOLVED: To accurately determine the SN ratio of the measurement signal of an eye fundus blood flow meter in a short time so that, when the SN ratio is poor, a process is performed for precluding measurement or for regarding the poor SN ratio as resulting from a measurement error. SOLUTION: A blood vessel on the fundus oculi of an eye E to be examined is irradiated with coherent measurement light, and signal light derived from scattering of the measurement light by particles within the blood vessel and reference light scattered from peripheral tissue are received; a spectrum distribution resulting from the frequency analysis of those reflected light signals is divided into at least two regions, that is, a noise region approximated to a white noise existing in a high frequency range, and a signal region existing at a lower frequency than the noise region. For this division, an integrated curve accumulated from high frequencies is originated, after which the integrated curve and its approximate straight line are obtained in two signal regions; an SN ratio is calculated from the two Y-axis sections thereof. Thus, by dividing the spectrum distribution into the signal region and the noise region, it can be effectively used, not only in the calculation of the SN ratio but also in subsequent velocity analysis.</p> |
