(Color online) Performance summary of various speckle-reduction filters applied to a bovine retina OFDI image. (a) and (b) show SNR, ENL, and CNR computed for each case. The results of (a) have been obtained by filtering the final image after angle compounding (postcompounding), whereas the results of (b) have been obtained by filtering each individual angle before forming the final angle compound image (precompounding). (c) and (d) show the average FOM for (a) and (b), respectively. (e) and (f) show the MSE of each filter, as defined in Eq. (2). N, number of angles; NF, no filtering; CNR, contrast-to-ratio; SNR, signal-to-noise ratio; ENL, equivalent number of looks; FOM, figure of merit; MSE, mean-square error; “(Linear),” filter applied to linear image as opposed to the logarithmic image. Only promising linear filter results are shown.

(Color online) Image recovery results for the à trous wavelet-transform-based filters (1 and 2), the ELEE, and the adaptive Wiener filters applied to the unfiltered images (postcompounding filtering). N number of angles; linear, filter applied to the linear image as opposed to the logarithmic image. The dashed line in the unfiltered N=1 image corresponds to the 400th A line, where the cross section of Fig. 3 is taken. Each image has 1000 A lines, where the distance between two adjacent A lines is ∼5 μm. There are 370 pixels shown for each A line covering a depth of 2.47 mm in air.

(Color online) Recovery results for the retina edge in a single A line (400th line of Fig. 2) for N=1, 4, 16, and 64. The edge of the retina boundary is shown for the NF image as well as for the filtered images. The y axis is in normalized decibel units. Linear, filter applied to the linear image as opposed to the logarithmic image.

(Color online) Recovery results for the wavelet-transform-based filters (Refs. [17,18]) applied to each angle separately and then added in linear units (precompounding filtering). N number of angles; linear, filter applied to the linear image as opposed to the logarithmic image. Each image has 1000 A lines, where the distance between two adjacent A lines is ∼5 μm. There are 370 pixels shown for each A line covering a depth of 2.47 mm in air.

(Color online) Recovery results for the ELEE and the adaptive Wiener filters applied to each angle separately and then added in linear units (precompounding filtering). N, number of angles. Each image has 1000 A lines, where the distance between two adjacent A lines is ∼5 μm. There are 370 pixels shown for each A line covering a depth of 2.47 mm in air.

(Color online) Comparison of the performance of precompounding versus postcompounding. In this comparison N=4 is used. Each image has 250 A lines, where the distance between two adjacent A lines is ∼5 μm. One hundred pixels are shown for each A line covering a depth of 0.67 mm in air.

(Color online) Same as Fig. 6, except N=8.

(Color online) Image recovery results for the à trous wavelet-transform-based filters (1 and 2), the ELEE, and the adaptive Wiener filters applied to the unfiltered image (top image) of an ex vivo human colon tissue imaged using an OFDI system. N=1 is used. Each image has 250 A lines, where the distance between two adjacent A lines is ∼5 μm. There are 210 pixels shown for each A line covering a depth of 1.40 mm in air.