The present invention provides a method for solving the Navier-Stokes equation of viscous, incompressible laminar flows with moving free surfaces in complex domains. The semiconductor memory device compensates the latency and test errors between two signals by detecting the latency of the two signals and stacking the reference data without using an extra signal. In at least some embodiments the camera can be synchronized with the duty cycle of the display screen to capture image information between duty cycles of the display screen, such that the light from the display does not saturate the camera.