Descent Camera data sets

Data Set Overview

This data set contains data acquired by the MER Descent Camera. The images were used for onboard realtime analysis of the descent path of the MER landing system while descending to the surface of Mars.

Processing

This data set uses the Committee on Data Management and Computation (CODMAC) data level numbering system. The MER Camera Payload EDRs are considered Level 2 or Edited Data (equivalent to NASA Level 0). The EDRs are to be reconstructed from Level 1 or Raw Data, which are the telemetry packets within the project specific Standard Formatted Data Unit (SFDU) record. They are to be assembled into complete images, but are not radiometrically or geometrically corrected.

Descent Camera EDR data products were generated by the Multi-mission Image Processing Lab at the Jet Propulsion Laboratory using the telemetry processing software mertelemproc. The EDRs produced are raw uncalibrated data reconstructed from telemetry packet SFDUs and formatted according to the Camera EDR/RDR Software Interface Specification. Meta-data acquired from the telemetry data headers and a meta-data database were used to populate the PDS label. There will not be multiple versions of a MER Camera Payload EDR. Missing packets will be identified and reported for retransmission to the ground as partial datasets.

Data

A downsampled EDR is a smaller version of the 1024x1024 full frame or subframed image using the following methods: 1) nearest neighbor pixel averaging, 2) pixel averaging with outlier rejection or 3) computing the median pixel value. Downsampled EDRs are stored as 16-bit signed integers. If 12-to-8 bit scaling is performed, then pixels are stored in 16-bit format and only the last 8 bits of the 16-bit integer are used.

Software

MER Camera Payload downlink processing software is focused on rapid reduction, calibration, and visualization of images in order to make discoveries, to accurately and expeditiously characterize the geologic environment around the rover, and to provide timely input for operational decisions concerning rover navigation and Instrument Deployment Device (IDD) target selection. Key software tools have been developed at JPL by the Multimission Image Processing Laboratory (MIPL). These tools were also used to process Pancam and MI images.

PDS-labeled images and tables can be viewed with the program NASAView, developed by the PDS and available for a variety of computer platforms from the PDS web site . There is no charge for NASAView.

Media/Format

The data set will initially be delivered and kept online. Upon Mission completion, the Descent Camera EDRs will be delivered to PDS on DVD as part of the complete MER EDR data set.