The Landsat 7 spacecraft and its Enhanced Thematic Mapper Plus (ETM+) were launched on April 15, 1999. Pre-launch modeling of the ETM+ optical system predicted that modulation transfer function (MTF) performance would change onorbit. A method was developed to monitor the along-scan MTF performance of the ETM+ sensor system using on-orbit data of the Lake Pontchartrain Causeway in Louisiana. ETM...

We present a new method to measure the modulation transfer function (MTF) beyond the Nyquist frequency of a multichannel imaging system for which all the channels have parallel optical axes. Such a multichannel optical system produces a set of undersampled subimages. If the subimages contain nonredundant information, high spatial frequencies are folded between low spatial frequencies, leading t...

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 ...

In an attempt to detect patients in an early stage of glaucoma, a new screening test, the Flicker System, by which temporal modulation transfer function is evaluated, was performed in 64 normal-tension glaucoma patients and 65 normal eyes. The early stage of glaucoma, i.e., stage 0-1 of Aulhorn-Greve's classification, showed a significant decrease of the modulation in the range from 20 to 45 Hz...

A new readout structure is investigated for signal-processing-in-the-element detectors that yields a modulation transfer function that is 3.5 dB better than those currently used. Experimental verification is performed in Si rather than HgCdTe, with similarity relations derived for the two semiconductors.

This paper describes a technique for synthesizing any noise shaping transfer function (NTF) starting from an N-Path Sigma Delta architecture. The proposed method uses cross-coupled paths to obtain missing terms in the NTF. The limitations due to zeros located out of the band of interest, as it happens for conventional N-Path Σ∆ modulators, are avoided. Specific NTFs are synthesized and behaviou...

Modulation-transfer-function (MTF) measurement often involves the use of three- and four-bar resolution targets. In the conversion of three- and four-bar image data to MTF, biased results can occur when we use series-expansion techniques appropriate for square-wave targets of infinite extent. For systems where the image data are digitally recorded, a convenient and accurate conversion of bar-ta...