Landsat Missions
The new Modulation Transfer Function Compensation (MTFC) parameters for the Landsat 7 Calibration Parameter File (CPF) were submitted for inclusion in the 4Q2001 CPF release. The new coefficients used in the CPF are derived from on-orbit estimates of the Enhanced Thematic Mapper Plus (ETM+) along- and across-scan MTF and replace the previous coefficients, which were based on prelaunch MTF measurements in the along-scan direction only. The MTF describes how the sensor optics and electronics modulate the original signal (image), as a function of spatial frequency, in the conversion of input radiance at the ETM+ aperture to an output digital image. The goal in MTFC resampling is to partially compensate for the system response by boosting the higher spatial frequencies attenuated by the MTF. This enhances fine spatial detail (e.g., edges) but has the side effect of also increasing the image noise somewhat. This is apparent in the sample images below where the MTFC image exhibits sharper edges but also has a grainier appearance. While no resampling method is perfect, we feel that the MTFC resampling provides a higher degree of image sharpness than other methods while maintaining fairly good truth in measured radiance. Users should evaluate the relative importance of image sharpness versus noise to their applications in deciding whether MTFC processing is appropriate.
The following images show Band 8 data subsets of the Meadowlands Sports Complex in New Jersey. These images show the improvements that can be seen in MTFC resampling compared to a Level 0 product, Nearest Neighbor resampling, and Cubic Convolution resampling methods.
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| Figure 1. Level 0 Product | Figure 2. Level 1 NN (Nearest Neighbor) Product |
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| Figure 3. Level 1 CC (Cubic Convolution) Product | Figure 4. Level 1 MTF (Modulation Transfer Function) Product |
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://landsat.usgs.gov
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Page Contact Information: landsat@usgs.gov
Page Last Modified: May 09, 2008
