A stellar energy extraction method based on exponential intra-pixel sensitivity model

The stability and accuracy of stellar energy extraction are important factors affecting the accuracy of in-orbit radiation calibration based on stars. However, the point spread function (PSF) and the intra-pixel sensitivity (IPS) of the infrared detector will have a great influence on the stability and accuracy of the point target energy extraction. To solve the above problems, this paper proposes a stellar energy extraction method based on an exponential intra-pixel sensitivity model. First, reconstruct the background image based on the multi-frame images to remove the influence of the instrument background. Then, each pixel was divided into 10 × 10 sub-pixels, and the value of each sub-pixel was obtained by fitting the target response value with a two-dimensional Gaussian function. Then, the exponential intra-pixel sensitivity model was established to obtain the IPS value of each sub-pixel, and the target response was deconvolved with the established IPS model. Finally, the star energy is obtained by the aperture photometry method. According to the simulation results, the accuracy of the proposed method is 0.4%, which is 15.6% higher than that without the IPS model; the stability of the proposed method is 0.5%, which is 5.6% higher than that without the IPS model. According to the experimental results using infrared star images observed in orbit, the accuracy of the proposed method is better than 3%, which is 13% higher than that without the IPS model; the stability of the proposed method is better than 3%, which is 5% higher than that without the IPS model. This method can provide a useful reference for the high-accuracy on-orbit star calibration of a large-aperture infrared remote sensing camera in space.