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Mapping without the sun
Zhang, Jixian

Fig 5 MTF estimation results using knife-edge method
Fig 8 Error analysis result
It is clear that MTF estimation from three different targets
obtain relatively consistent results. However, site 3 obtains
lower MTF and the most error at Nyquist frequency is about
0.018, which may result from lower contrast and bigger slope.
7.2 Pulse method target and result
The target used for pulse method is a dam between different
fish ponds in the same scene as knife-edge method, it is shown
in figure 6 and MTF estimation result is shown in figure 7.
Fig 6 Pulse target for SPOT/Pan MTF estimation
Fig 7 MTF estimation result using pulse method
Because the input pulse is about 1.5 pixels, the first
zero-crossing is located at normalized frequency of 0.6, which
leads to the bad result aty^ v = o.6 •
7.3 Analysis
Figure 8 shows the relative difference between knife-edge and
pulse method. The biggest error reaches to 0.085, but it is cause
by zero-crossing. In other frequency domain, the biggest error
is about 0.04, which indicate that the accuracy of MTF
estimation methods is quite reasonable.
Modulation transfer function (MTF) is a key measurement of
imaging systems’ geometric performance. It is not only an
indicate the performance of imaging system, but also make a
deconvolution filter whose purpose is to enhance image
contrast by ground processing.
This paper systematically introduces the principle of several
widely-used on-orbit MTF estimation methods (including point
source/array method, knife-edge method; pulse method, and
bi-resolution method), their target deployment/selection
standards, data processing steps, and their advantages and
drawbacks. We should choose the optimal method according
the spatial resolution of sensor and target condition. We hope to
accelerate the construction of remote sensing data quality
analysis and assessment system with self-dominated
intellectual property right through the studies and
implementation of on-orbit MTF estimation.
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assessment of satellite cameras, Post-launch calibration of
satellite sensors: P.67-76, Taylor & Francis Group, 2004.
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“Landsat Thematic Mapper image-derived MTF”,
Photogrammetric Engineering & Remote Sensing, Vol.51,
No.9: P.1395-1406, 1985.
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orbit modulation transfer function (MTF) measurement
using edge and pulse Method", South Dakota State
University, 2002.
[4] Manjunath Kempaiah Rangaswamy, “Quickbird II
two-dimensional on-orbit modulation transfer function
analysis using convex mirror array”, South Dakota State
University, 2003.
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characterization of spatial quality using point spread
function, Post-launch calibration of satellite sensors:
P.151-170, Taylor & Francis Group, 2004.
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sources: evaluation of performances”, In: IGARSS 1991:
P.1357-1361, 1991.