Modified slanted-edge method and multidirectional modulation transfer function estimation

Abstract

The slanted-edge method specified in ISO Standard 12233, which measures the modulation transfer function (MTF) by analyzing an image of a slightly slanted knife-edge target, is not robust against noise because it takes the derivative of each data line in the edge-angle estimation. We propose here a modified method that estimates the edge angle by fitting a two-dimensional function to the image data. The method has a higher accuracy, precision, and robustness against noise than the ISO 12233 method and is applicable to any arbitrary pixel array, enabling a multidirectional MTF estimate in a single measurement of a starburst image.

Dynamic Modulation Transfer Function Analysis of Images Blurred by Sinusoidal Vibration

“…In Fig. 7(a), the pixels in the rectangular region of interest (ROI) are projected along the gradient direction into the bins whose width is a quarter of the sampling frequency on the horizontal axis [16]. The one-dimensional edge spread function (ESF) is generated by averaging the values of the pixels in each bin in Fig.…”

Resolution enhancement in active underwater polarization imaging with modulation transfer function analysis

“…The standard slanted-edge method specified in ISO 12233 [23,24] measures the MTF by using a digital imaging device and a knife-edge target. The edge of the target is slanted at a certain angle such as 5°in some MTF studies.…”

An Experimental Comparison Of Directly And Indirectly Derived Modulation Transfer Functions

“…In real images, two additional issues have to be addressed: the first is the phase problem which occurs during the discrete sampling of the ESF; the second is noise. The former can be addressed by photographing a slightly slanted edge (Storey, ; Choi and Helder, ; Masaoka et al., , ; Javan et al., ), the latter could be mitigated by aggregation of a sufficient number of profiles of the same edge.…”

“…This method is similar to that applied by Choi () except that Li calculated a simple average from all measured LSF profiles to obtain the location of the edge, while Choi used an interpolation procedure to locate the precise position of the edge in considering the phase shift of edges. Another possibility for locating the edge is to fit a cumulative distribution function (CDF) directly onto the aggregated ESF (Masaoka et al., ).…”