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. 2017 Apr 24;11:781–790. doi: 10.2147/OPTH.S133070

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© 2017 Miyagawa et al. This work is published and licensed by Dove Medical Press Limited

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Procedures for the SFF method.

Notes: (1) An averaged and cropped image generated by the averaging process. (2) Frequency domain image obtained by FFT. (3) A filtered image. An appropriate frequency domain band-pass filter was applied and converted to spatial domain image by iFFT. (4) Results of cone photoreceptor identification. Peak points on a filtered image were taken to be cone photoreceptor cells. Red points indicate detected peak points as individual cells. The magnification is approximately 60 × 50 µm. The square image area is not equivalent to the square area on the retina because of the correction for the distortion of the raw digital image.

Abbreviations: SFF, spatial frequency filtering; FFT, fast Fourier transform; iFFT, inverse FFT.