  This paper introduces an elasticity reconstruction method based on local
displacement observations of elastic bodies. Sparse reconstruction theory is
applied to formulate the underdetermined inverse problems of elasticity
reconstruction including unobserved areas. An online local clustering scheme
called a superelement is proposed to reduce the number of dimensions of the
optimization parameters. Alternating the optimization of element boundaries and
elasticity parameters enables the elasticity distribution to be estimated with
a higher spatial resolution. The simulation experiments show that elasticity
distribution is reconstructed based on observations of approximately 10% of the
total body. The estimation error was improved when considering the sparseness
of the elasticity distribution.
