Normally, free surface elevation measurements, both in the coastal field and laboratory, mostly use traditional wave gauges such as capacitance, resistance, and conductivity types. These types of equipment take intrusive measurements, as they disturb the wave propagation. This study focuses on an alternative technique, namely an image processing and analysis approach based on the canny edge detection and water elevation comparing algorithm in Matlab. Five experimental case studies of water surface elevation changes were carried out in a wave flume 0.60 m wide, 18 m long, and 0.75 m high. The results showed that the average wave heights and wave periods measured using both methods are different by not more than 9.26% and 0.49%, respectively. Moreover, the statistical agreement of water surface elevations in term of MSE, RMSE, and R2 confirmed that image processing is as good as the conventional method and can be used in the laboratory as well.