Bragg Coherent Diffraction Imaging has been applied to nanomaterial characterization for imaging atomic movement and phase transformation. Its ability to produce unique three-dimensional defect and displacement field images has been extremely helpful for understanding material property under different environment, such as energy cells or optical materials in various working conditions. In this study, we use computer simulations to reveal the influence of Poisson noise on the resultant reconstruction images of atomic defects within a nanoparticle. The study focuses mainly on dislocation imaging, including dislocation loops. By simulating the reconstructions under different Poisson noise level, we defined the threshold of the Poisson Noise level for different number of dislocations in the atomic structure. We have also discovered the effects of the size and shape of the dislocation loops.