Table 1.
Mastcam and MARDI Instrument Characteristics
| Hardware Element | Mass (kg) | Power (w) | Dimensions (cm) |
|---|---|---|---|
| Mastcam 34 mm | 0.799 | 1.8 idle, 3.5 imaging | 27 × 12 × 11 |
| Mastcam 100 mm | 0.806 | 1.8 idle, 3.5 imaging | 27 × 12 × 11 |
| MARDI | 0.559 | 1.8 idle, 3.5 imaging | 15 × 11 × 11 |
| Digital electronics assembly (DEA) includes 2 Mastcams, MAHLI, and MARDI | 2.089 | 6.4 idle, 9.0 imaging | 22 × 12 × 10 |
| Mastcam calibration target | 0.079 | None | 8 × 8 × 6 |
| MARDI calibration target | NA | None | 34 × 93 |
| Optics | Description | ||
| Mastcam 34 mm | Mastcam 100 mm | MARDI | |
| Field of view (FOV, diagonal) | 20.6° | 7.0° | 90° |
| FOV (horizontal 1200 pixels)a | 15.0° | 5.1° | 70° |
| FOV (vertical 1200 pixels) | 15.0° | 5.1° | 52° |
| Instantaneous field of view (IFOV) | 218 μrad | 74 μrad | 764 μrad |
| Focal ratio | f/8 | f/10 | f/3.0 |
| Effective focal length | 34.0 mm | 99.9 mm | 9.7 mm |
| Focus range | 0.5 m to infinity | 1.6 m to infinity | 2 m to infinity; ~1 mm resolution at surface |
| Band passes | Figure 3 | Figure 3 | 399–675 nm with Bayer pattern filter |
| Detector | Description | ||
| Product | Kodak KAI‐2020CM interline transfer CCD | ||
| Color | Red, green, and blue microfilters; Bayer pattern | ||
| Array size | 1640 × 1214 pixels, 1600 × 1200 photoactive pixels; typical image size was 1344 × 1200 | ||
| Pixel size | 7.4 μm (square pixels) | ||
| M‐34 gain, read noise, full well | 16.0 e −/DN | 18.0 e − | 26,150 e − |
| M‐100 gain, read noise, full well | 15.8 e −/DN | 15.8 e − | 23,308 e − |
| MARDI gain, read noise, full well | 15.8 e −/DN | 17.5 e − | 29,454 e − |
| Exposure | Description | ||
| Duration | 0 to 838.8 s; commanded in units of 0.1 ms | ||
| Auto‐exposure | Based on Mars rover engineering camera approach of Maki et al. [2003] | ||
| Video acquisition | Description | ||
| Modes | Acquire and store single‐image frames or acquire and immediately compress into groups of pictures (GOPs) | ||
| Frame rate | Maximum limited by signal transmission rate between camera head and DEA to <4 Hz | ||
| Compression | Frames stored individually are treated the same as individual nonvideo images; GOPs are JPEG‐compressed | ||
| Onboard data compression options | Description | ||
| Uncompressed | No compression; no color interpolation | ||
| Lossless | Approximately 1.7:1 compression; no color interpolation | ||
| Lossy | JPEG; color interpolation or gray scale; commandable color subsampling Y:CR:CB (4:4:4 or 4:2:2); commandable compression quality (1–100) | ||
| Video GOP | JPEG‐compressed color‐interpolated GOPs, up to 2 Mb file size and up to 16 frames per GOP; commandable color subsampling and compression quality | ||
| Deferred compression | Image stored in onboard instrument DEA uncompressed; specified compression performed at a later time for transmission to Earth | ||
| Stereo pair acquisition | |||
| The two Mastcam camera heads can be used to acquire stereo image pairs, which requires resampling to match the pixel scales between the two cameras; the cameras have an interoccular distance of 24.64 cm and a toe‐in angle between the two Mastcams is 2.5° | |||
| The MARDI camera head is fixed‐mounted to the rover body; stereo pairs can only be acquired by motion of the rover—during descent and, after landing, by driving |
| Mosaic acquisition | |||
|
Mastcam mosaic acquisition requires use of software planning tools and RSM motion to scan the camera head FOVs over the desired scene, typical overlap was 20% (top‐to‐bottom/side‐to‐side) MARDI is fixed‐mounted to the rover body; mosaics are only acquired by motion of the rover—during descent and, after landing, by driving |
| Mastcam onboard focus merge | Description (unavailable on MARDI) | ||
| Products | Best focus image (color) and range map (gray scale) | ||
| Maximum input image size | 1600 × 1200 pixels; input images must be same size | ||
| Maximum number of input images | 8 images of 1600 × 1200 pixels | ||
| Input image compression | Raw, uncompressed (no color interpolation) | ||
| Output image compression | JPEG with user‐specified compression quality | ||
| Processing options | Merge, registration (feature tracking + corner detection), blending (spline‐based) | ||
| Image thumbnails | Description | ||
| Size | Approximately 1/8th the size of the parent image; size in integer multiples of 16 rounded down (thus, the thumbnail for a 1600 × 1200 pixel parent image is 1600/8 = 200/16 = 12.5 ≥ 12 × 16 yields 192 and 1200/8 = 150/16 = 9.375 ≥ 9 × 16 = 144, so the thumbnail is 192 × 144 pixels) | ||
| Purpose | Provides an index of images acquired by and stored onboard instrument; returned to Earth, often in advance of parent image, for evaluation and decision‐making about on‐Mars event success, data downlink compression, and priority | ||
| Compression | Commandable compressed or uncompressed; typical thumbnails from Mars are 4:4:4 color JPEGs; commandable compression quality | ||
| Video GOP | One thumbnail per GOP, derived from first image in GOP | ||
Note that the horizontal FOV is not limited to 1200 active pixels. The full 1600 active pixels are illuminated (though vignetted), and the M‐100 FOV is 16/12 × 5.1° across (~6.8°), and the M‐34 is 16/12 X 15° = 20°.