  The diffuse morphology and transient nature of coronal mass ejections (CMEs)
make them difficult to identify and track using traditional image processing
techniques. We apply multiscale methods to enhance the visibility of the faint
CME front. This enables an ellipse characterisation to objectively study the
changing morphology and kinematics of a sample of events imaged by the Large
Angle Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric
Observatory (SOHO) and the Sun Earth Connection Coronal and Heliospheric
Investigation (SECCHI) onboard the Solar Terrestrial Relations Observatory
(STEREO). The accuracy of these methods allows us to test the CMEs for
non-constant acceleration and expansion.
  We exploit the multiscale nature of CMEs to extract structure with a
multiscale decomposition, akin to a Canny edge detector. Spatio-temporal
filtering highlights the CME front as it propagates in time. We apply an
ellipse parameterisation of the front to extract the kinematics (height,
velocity, acceleration) and changing morphology (width, orientation).
  The kinematic evolution of the CMEs discussed in this paper have been shown
to differ from existing catalogues. These catalogues are based upon
running-difference techniques that can lead to over-estimating CME heights. Our
resulting kinematic curves are not well-fitted with the constant acceleration
model. It is shown that some events have high acceleration below $\sim$5
R$_{\sun}$. Furthermore, we find that the CME angular widths measured by these
catalogues are over-estimated, and indeed for some events our analysis shows
non-constant CME expansion across the plane-of-sky.
