When spatially dense mobility shapes are measured with scanning laser Doppler vibrometers, it is often impractical to use phase-separation modal parameter estimation methods due to the excessive number of highly coupled modes and to the prohibitive computational cost of processing huge amounts of data. To deal with this problem, a data compression method using Chebychev polynomial approximation in the frequency domain and two-dimensional discrete Fourier series approximation in the spatial domain, is proposed in this article. The proposed space-frequency regressive approach was implemented and verified using a numerical simulation of a free-free-free-free suspended rectangular aluminum plate. To make the simulation more realistic, the mobility shapes were synthesized by modal superposition using mode shapes obtained experimentally with a scanning laser Doppler vibrometer. A reduced and smoothed model, which takes advantage of the sinusoidal spatial pattern of structural mobility shapes and the polynomial frequency-domain pattern of the mobility shapes, is obtained. From the reduced model, smoothed curves with any desired frequency and spatial resolution can be produced whenever necessary. The procedure can be used either to generate nonmodal models or to compress the measured data prior to modal parameter extraction. © 1996 John Wiley & Sons, Inc.32127133Arruda, J.R.F., Surface Smoothing and Partial Spatial Derivatives Computation Using a Regressive Discrete Fourier Series (1992) Mechanical Systems and Signal Processing, 6 (1), pp. 41-50Arruda, J.R.F., Spatial Domain Modal Analysis of Lightly Damped Structures Using Laser Velocimeters (1993) Journal of Vibration and Acoustics, 115 (3), pp. 225-231Arruda, J.R.F., Mitchell, L.D., Sun, F., Spatial Domain Techniques for Modal Analysis Using a Laser Doppler Velocimeter (1992) Proceedings of the X International Modal Analysis Conference, pp. 656-664. , San Diego, CADippery, K.D., Phillips, A.W., Allemang, R.J., Condensation of the Spatial Domain in Modal Parameter Estimation (1994) Proceedings of the XII International Modal Analysis Conference, pp. 818-824. , Honolulu, HawaiiEwins, D.E., (1984) Modal Testing: Theory and Practice, , Research Studies Press, Letchworth, Hertfordshire, EnglandHalvorsen, W.G., Barney, P.S., Brown, D.L., Developing Impedance-Type Models of Structural/Acoustic Systems (1991) Sound and Vibration, 25 (8), pp. 18-26Huang, T.S., (1981) Two-Dimensional Digital Signal Processing II - Transforms and Median Filters, , Springer-Verlag, Berlin, GermanyLi, W.X., Mitchell, L.D., Lu, M., Non-Modal Method of Structure Dynamic Response Identification for a Prototype Commercial (1993) Proceedings of the XII International Modal Analysis Conference, pp. 255-261. , Honolulu, HILyon, R.H., (1975) Statistical Energy Analysis, , The MIT Press, Cambridge, MAShih, C.Y., Tsuei, Y.G., Allemang, R.J., Brown, D.L., A Frequency-Domain Global Parameter Estimation Method for Multiple Reference Frequency Response Measurements (1988) Mechanical Systems and Signal Processing, 2 (4), pp. 349-365Sun, F.P., Mitchell, L.D., Arruda, J.R.F., Mode Decoupling Considerations in Mode Shape Measurements of a Plate with Monoexcitation and Laser Doppler Vibrometer (1993) Experimental Techniques, 17 (4), pp. 31-37