Fast color Fourier ptychographic microscopy based on spatial filtering frequency fusion

•Owing to the high throughput, high color accuracy, and fast characteristics of SFCFPM, it is practical for digital pathology.•The study describes the relationship between color and texture in color FPM by establishing a spectrum filtering model.•The SFCFPM can reduce the acquisition and reconstruction time by 2/3 compared with the traditional color FPM scheme.•The accuracy can be improved by 65.21% compared with the traditional color FPM scheme.•The SFCFPM scheme has good adaptability to both existing reconstruction and correction algorithms. High-throughput, highly color-accurate full-color images have high application value in digital pathology and can provide valuable information in the corresponding pathology section analysis. Fourier ptychographic microscopy (FPM) is a new computational microscopy imaging technique, which breaks through the diffraction limit of traditional microscopy via the optical synthesis of aperture. Thus, FPM technology has been widely used in digital pathology. However, the use of the traditional RGB channel reconstruction color FPM to achieve full-color imaging and acquire and reconstruct images is computationally extensive. Moreover, during the reconstruction process, the low-frequency portion of the reconstructed image varies with factors such as fluctuations in the light intensity and exhibits a color bias, resulting in the loss of a certain degree of color accuracy. To address these challenges, this study proposes a fast color FPM scheme based on spatial filtering frequency fusion (SFCFPM). The scheme describes the frequency fusion relationship between color and texture in color FPM by establishing a spectrum filtering model for color FPM. Based on the guidance of this model, the SFCFPM scheme extracts high-resolution (HR) images reconstructed by a single channel FPM and fuses them with low-resolution (LR) color images acquired using a low-magnification objective to obtain HR color images with a large field-of-view. Moreover, the SFCFPM can reduce the acquisition and reconstruction time by 2/3 compared with the traditional RGB channel reconstruction color FPM scheme. Furthermore, compared with the fast color FPM scheme that requires coloring, the coloring time can be reduced from tens to hundreds of seconds to less than 0.1 s, and the accuracy can be improved by 65.21 % compared with the RGB channel reconstruction, which enables SFCFPM to further promote the application of color FPM technology in the field of digital path