Abstract. The measurement of weak gravitational lensing is currently limited to a precision of ~10% by instabilities in galaxy shape measurement techniques and uncertainties in their cali-biation. The potential of large, on-going and future cosmic shear surveys will only be realised with the development of more accurate image analysis methods. We present a description of several possible shear measurement methods using the linear "shapelets" decomposition. Shapelets piovides a complete reconstruction of any galaxy image, including higher-oider shape moments that can be used to generalise the KSB method to arbitrary order Many independent shear estimators can then be formed for each object, using linear combinations of shapelet coefficients These estimators can be treated separately, to improve their overall calibration; or combined in more sophisticated ways, to eliminate various instabilities and a calibration bias We apply several methods to simulated astronomical images containing a known input shear, and demonstrate the dramatic improvement in shear recovery using shapelets A complete IDL software package to perform image analysis and manipulation in shapelet space can be downloaded from www. astro. caltech.. edu/~rjm/shapelets/.
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