1992 年 12 巻 1Supplement 号 p. 127-130
The spatio-temporal derivative method for flow field image measurement is well known as a high spatial resolution technique. The governing equations are derived using Lagrange derivative, and assuming that the visualized particle image pattern varies smoothly almost everywhere. The authors examine the formulation of governing equation and the brightness function of the flow image in detail, and try to extend this technique to the theory with higher order approximation. The new governing equation can be applied to the case of illumination intensity is not uniform in measurement area.