For optoelectronic detection systems such as an infrared scanning payload, the reduction of the Instantaneous Field of View (IFOV) is important for background cluster suppression, detection probability improvement and false alarm rate decreasing. An oversampling technique is always the research hotspot for the improvement of the imaging resolution of an imaging instrument. In view of a point target detection system, the normal sampling and oversampling techniques are compared with each other. The result shows that the oversampling technique has its obvious advantages in the respects of standard response deviation, average response and PEE.