This paper presents an extension of the phase correlation method to subpixel registration. The authors derive analytic expressions for the phase correlation of downsampled images, showing that the signal power in the phase correlation is not concentrated in a single peak but rather in several coherent peaks. These peaks correspond to the polyphase transform of a filtered unit impulse centered at the point of registration. The analytic results provide a closed-form solution to subpixel translation estimation and are used for detailed error analysis. The method is shown to be effective for subpixel translation estimation of images of different nature and across different spectral bands. The paper begins by discussing the importance of subpixel registration in remote sensing and biomedical imaging. It then reviews various methods for subpixel registration, including interpolation-based methods and methods based on the differential properties of image sequences. The authors propose a new approach based on the phase correlation method, which is extended to subpixel registration by deriving analytic expressions for the phase correlation of downsampled images. The paper then presents the properties of the phase correlation method, including its accuracy in detecting peaks and its robustness to noise. It also discusses the handling of blurred images and the effects of aliasing and periodicity assumptions. The authors then present their extension of the phase correlation method to subpixel registration, showing that the method can be used to estimate subpixel shifts by analyzing the coherent peaks in the phase correlation. The paper includes an error analysis of various sources of error, including the approximation of the Dirichlet kernel by a sine function, nonoverlapping regions, aliasing, and border errors. The authors also discuss the effects of wide-band random noise and the importance of prefiltering to reduce aliasing errors. The paper concludes with experimental results showing the effectiveness of the method in subpixel registration across different image modalities and spectral bands. The results demonstrate that the phase correlation method provides accurate subpixel registration with high precision and robustness to noise.This paper presents an extension of the phase correlation method to subpixel registration. The authors derive analytic expressions for the phase correlation of downsampled images, showing that the signal power in the phase correlation is not concentrated in a single peak but rather in several coherent peaks. These peaks correspond to the polyphase transform of a filtered unit impulse centered at the point of registration. The analytic results provide a closed-form solution to subpixel translation estimation and are used for detailed error analysis. The method is shown to be effective for subpixel translation estimation of images of different nature and across different spectral bands. The paper begins by discussing the importance of subpixel registration in remote sensing and biomedical imaging. It then reviews various methods for subpixel registration, including interpolation-based methods and methods based on the differential properties of image sequences. The authors propose a new approach based on the phase correlation method, which is extended to subpixel registration by deriving analytic expressions for the phase correlation of downsampled images. The paper then presents the properties of the phase correlation method, including its accuracy in detecting peaks and its robustness to noise. It also discusses the handling of blurred images and the effects of aliasing and periodicity assumptions. The authors then present their extension of the phase correlation method to subpixel registration, showing that the method can be used to estimate subpixel shifts by analyzing the coherent peaks in the phase correlation. The paper includes an error analysis of various sources of error, including the approximation of the Dirichlet kernel by a sine function, nonoverlapping regions, aliasing, and border errors. The authors also discuss the effects of wide-band random noise and the importance of prefiltering to reduce aliasing errors. The paper concludes with experimental results showing the effectiveness of the method in subpixel registration across different image modalities and spectral bands. The results demonstrate that the phase correlation method provides accurate subpixel registration with high precision and robustness to noise.