Abstract-In hyper spectral imaging applications, the light power reaching the image sensofr is greatly reduced compared to broadband color image sensors. Consequently, some typical algorithms, such as Flat Field Correction (FFC), are not guaranteed anymore to work in the same way as in their normal operation for broadband color imaging. This is caused by transistor leakage which cannot be neglected anymore. In this paper, we propose a mathematical leakage model based on the basic transistor theory to tag the validity of the sensor response. The model has been validated by comparing the simulation results to measurements of the pixel response of a hyper spectral imager. We also demonstrate that this leakage model is able to select the proper training set for a typical FFC algorithm.Index Terms-Leakage model, transistor leakage, CMOS imager, hyper spectral imaging, flat field correction.