Hazcam data sets

Data Set Overview

This data set contains images acquired by the Hazcams for the support of rover traverse planning, post-traverse assessment, rover localization, operation of the instrument arm, and the selection of science targets. Most Hazcam images were commanded via ground commands from Earth, although a subset of Hazcam images were commanded autonomously during rover traverses by the Rover on-board autonomous navigation system. The proximity of the Hazcams to the Martian surface has resulted in a set of close-up views of the fine-grain texture of materials in the immediate vicinity of the rover. Hazcam image data often provide views of the surface not viewable by the Navcam and Pancam cameras.

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 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.

Hazcam 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 data sets.

Data

1. Full Frame EDR: Full Frame 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.
2. Thumbnail EDR: Thumbnail EDRs are stored as 16-bit signed integers or 8-bit unsigned 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. The Thumbnail EDR is a spatially downsampled version of the original acquired source image (all EDRs for a particular image are derive from the same source image). For example, in the case of subframe image products the thumbnail image represents the full-frame contextual image form which the subframe image data was extracted from. Note that the original acquired image is not always downlinked, and in some cases thumbnails are the only returned data for a particular observation. The main purposes of a Thumbnail EDR are to provide image previews and contextual information, both at a very low data volume compared to the original image.
3. Sub-frame: EDR Sub-frame EDRs are a subset of rows and columns of the 1024 x 1024 full frame image. Sub-frame 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.
4. Downsampled EDR: A downsampled EDR is a smaller version of the 1024 x 1024 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 Hazard Avoidance Camera EDRs will be delivered to PDS on DVD as part of the complete MER EDR data set.