Imager for Mars Pathfinder (IMP) image calibration

Abstract

Abstract. The Imager for Mars Pathfinder returned over 16,000 high-quality images from the surface of Mars. The camera was well-calibrated in the laboratory, with <5% radiometric uncertainty. The photometric properties of two radiometric targets were also measured with 3% uncertainty. Several data sets acquired during the cruise and on Mars confirm that the system operated nominally throughout the course of the mission. Image calibration algorithms were developed for landed operations to correct instrumental sources of noise and to calibrate images relative to observations of the radiometric targets. The uncertainties associated with these algorithms as well as current improvements to image calibration are discussed. The primary requirement for mission success was that IMP provide a color panorama of the landing site. Other science goals included contour mapping of the local terrain, multispectral imaging of the surrounding rocks and soils to study local mineralogy, viewing of three windsocks, measuring atmospheric opacity and water vapor content, and estimating the magnetic properties of wind-blown dust.In this paper we review the baseline IMP performance, expanding on the prelanding experiment report [Smith et al., 1997]. We then discuss several experiments that were performed postlaunch that verify the nominal performance of the camera system. Finally, we describe the algorithms used to calibrate raw image data and review the differences between the level of calibration performed during operations versus more current and pending calibration algorithm. Note that this document is primarily intended to review IMP calibration and performance. The full IMP calibration report [Reid et al., 1998] will be archived with the raw data by the Planetary Data System (PDS).

Low Abundance Materials at the Mars Pathfinder Landing Site: An Investigation Using Spectral Mixture Analysis and Related Techniques

“…Unfortunately, the patches are near the limit of resolution of the IMP camera, and a search of the Sojourner rover camera image archive revealed no closeup rover images of this particular rock. The material's limited spatial extent, coupled with the wavelength-dependent decrease in IMP spatial resolution and the generally lower calibration fidelity of the IMP 965-nm filter data (e.g., Reid et al 1999), results in relatively large uncertainties in the spectrum of this unit, especially at the longest wavelengths. The Anomalous Patches material spectrum in Fig.…”

“…There are a number of sources of potential systematic errors in the IMP calibration, including temporal and viewing geometry (phase function) differences between images of the scene and of the RCTs, and the changing balance of direct vs diffuse illumination of the surface depending on topographic slope, viewing azimuth, and time of day, and changes in the scattering properties of atmospheric aerosols (e.g., Tomasko et al 1999. Version 3 of the IMP calibration algorithm described by Reid et al (1999) and attempts to compensate for some of these potential sources of systematic errors by scaling the radiance values of a scene image by the ratio of the total downward flux at the time of RCT acquisition to the total downward flux at the time of scene acquisition. The algorithm uses an approximation to the sky model of Tomasko et al (1999) to essentially convert the scene brightnesses to values that they would be predicted to have had if observed simultaneously with the RCT images.…”

Spectroscopic properties of sintered BaMgAl10O17:Eu2+ (BAM) translucent pellets

“…This is of great importance since the reduction of weight, volume and equipment complexity is always the primary concern in such missions. Moreover, BAM luminescence occurs dominantly in a spectral region, where the Martian sky radiance (mainly reddish due to suspended ferric mineral dust) is comparatively weak [14,15]. This fact strongly favors the signal-to-noise ratio of the returned UV data.…”

Characteristics of the Pathfinder APXS sites: Implications for the composition of Martian rocks and soils

“…For IMP data we used the latest calibrations for radiance and reflectance [Reid et al, 1999a[Reid et al, , 1999b.…”