We are developing small animal PET/ SPECT scanner systems and high-definition small pixel-PSPMT type gamma cameras for them. These sensors are causing problems such as two-dimensional spatial nonlinearity, ununiformity and vagueness of pixel areas in scintillated images by unbalanced PMT gains or additional scattered photons’ influences. For overcoming these problems, we are providing look-up table type image correction units in the cameras. In order to determine appropriate image correction LUT data efficiently, we propose an assistant tool, which provides either automatic or interactive functions for designing correction tables. In this paper, we describe several features of our developed tool, and results of comparative experiments among four types of XYdimensional geometric correction methods supported by our tool.