Great breakthroughs have been made in research of ghost imaging in recent years. The application value of ghost imaging is increasingly obvious. The precondition of ghost imaging is that its light source should be random fluctuating thermal light. Presently, pseudothermal light is usually generated by passing a laser beam through a revolving ground glass. In view of the limitations of such a method, this paper proposes to generate pseudothermal light via sparse array independent source combining system, and discusses the differences between two algorithms, i.e., linear correlation algorithm and sparsity constraint nonlinear algorithm, in ghost imaging.