Blurring and noise are serious problems in hydro-test with high-energy X-ray radiography and make it difficult to reconstruct density distributions from radiographic images.A constrained optimization reconstruction method to decrease the blurring and noise impact is proposed.In this method,the parallel-beam X-ray projections are modeled by inserting a blurring matrix in.The optimization reconstruction problem is minimized by steepest descent method,and a preconditioned matrix has been adopted to improve the...