As a method of 3D-measurement of air flow velocity distribution from the images visualized with smoke particles, we have proposed the method that calculates 3D-velocity component from the gray level defference between two paralel planes.In this paper, we proposed a new image taking method to reduce measurement errors and inspect its performance through the application to CG(Computer Graphic) images.Moreover, the effects of some improvement such as 2D pattern tracking in subpixel accuracy and a new critical condition to eliminate doubtful 3-D component, are also inspected.
