Current theoretical polarization imaging models are based mostly on the assumption of ideal polarizers whose extinction ratio is significantly large and whose main direction is already known. However, the actual non-ideality of polarizers will have a significant impact on the accuracy of polarization imaging measurements. A correction model of visible light polarization imaging considering the non-ideality of polarizers was investigated to decrease this impact. Based on the Stokes vector polarization theory, a correction model of visible light polarization imaging considering the non-ideality of the polarizer was proposed by analyzing the change of the polarization state of the incident light caused by the actual polarizer. The corresponding calculation formulas for the degree of linear polarization (DoLP) and angle of polarization (AoP) were given. An experiment measuring the DoLP of the incident linearly polarized light via a time-division polarization imaging system was conducted. When the extinction ratio of the polarizer is 100∶1, the average relative error of the DoLP based on an ideal model is 5.53%, while the average relative error of the DoLP based on the correction model is reduced to 3.62%. Results show that the proposed correction model can effectively improve the accuracy of polarization information measurements. Using the proposed correction model can achieve a high DoLP measurement accuracy when the measurement system is constructed by a low extinction ratio polarizer. Furthermore, a larger field of view can be obtained at a lower cost.