Landsat Missions
The Level 1R data product is a radiometrically corrected L0R product. L1R products have three improvements: 1) detector artifacts, such as coherent noise, are corrected; 2) cosmetic artifacts, such as banding, striping, and dropped lines or pixels are also corrected; and 3) the L1R image is calibrated to radiance units (or color corrected) as integer values. Radiometric corrections are not reversible. As with L0R, pixels are not resampled nor are they geometrically corrected or registered, which means that the pixels are NOT aligned per scan line.
The Level 1 Radiometrically corrected (L1R) Scan Line Corrector (SLC)-off data product contains alternating areas of duplicated scan lines (14 pixels wide) along the edge of the scene (Figure 1). The width of the duplicated regions gradually diminishes toward the center of the scene. The center of the image contains nominal image data (Figure 2).
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| Figure 1. L1R product, showing duplication along the scene edge. | Figure 2. L1R product, showing nominal image data at the scene center. |
There are different approaches to correcting for the duplication of pixels on SLC-off products. The U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) provides the option of four techniques in order to produce the current L1G SLC-off products: 1) interpolating the missing values from neighboring scan lines; 2) replacing the duplicated lines with null values; 3) replacing the missing pixels with histogram-matched data from alternate acquisition dates; 4) using a multi-scale segmentation model to fill the gaps with same-scene data.
An Algorithm Theoretical Basis Document (ATBD) .pdf (156 KB) has been prepared for USGS processing of SLC-off Landsat 7 data. This information may also benefit users of other existing Level 1 processing systems.
To download samples of any SLC-off products, see the Sample Products page.
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 12, 2008
