超分辨成像是基于过采样来降低频率混叠、提高图像分辨率的技术，而像素有效形状是超分辨相关研究的重要对象。基于实际的红外焦平面阵型提出了“Z”形有效形状模型，并分析了常用的方形模型和“Z”形模型分别得到调制传递函数(MTF)的差别。还提出了形状边界到中心点的差值越小，其得到的MTF越大的假设，通过对不同形状模型的MTF推导分析和数值模拟，其结果证实了这一假设。数值模拟结果还表明圆形模型具有最大的MTF值。上述结论对未来的红外焦平面阵型设计与生产具有参考意义。

Super-resolution (SR) imaging is a technology based on oversampling to reduce the aliasing and increase the image resolution. Pixel active area (PAA) model is essential in SR related research. The difference of MTF with the widely used square model and the“Z” shape model we proposed was calculated to simulate the practical infrared focal plane array(IRFPA) production. The cause of the difference was analyzed. Furthermore, a hypothesis was proposed, which the smaller the difference between the closest and the farthest distances from the PAA boundaries to the pixel center, the greater the MTF of IRFPA will be. Different PAA shapes were discussed and the MTFs of these shapes were calculated. The calculation results verify the hypothesis we proposed. These results also show that the circle PAA is the most ideal model and it should be used as a reference for IR FPA design.