Traditional System | Full Spectral Imaging System |
General | |
| Transmits every byte acquired | Transmits all information acquired |
| Measures top of-the-atmosphere spectral radiance | Measures at-target spectral reflectance |
Instrument | |
| Utilizes light only in specific bands | Captures and uses all light |
| Individual bandpass calibration required | Full spectral response calibration required |
| Beamsplitters for VIS, SWIR, IR band separation | Separate focal planes for VIS, SWIR, IR band separation |
| Single large focal planes | Multiple small focal planes |
| External reference pointing stabilization system | Earth imaging referenced pointing stabilization system |
| Post processing correction for Earth rotation | Yaw and roll correction for Earth rotation compensation |
| Post processing geolocation | Real-time geolocation (associated with stabilization) |
| Smear reduction by limited exposure time | Forward motion compensation for smear reduction |
| On-board radiometric calibration system | No on-board radiometric calibration system |
On-Board Processing | |
| Generates data as bytes per band | Generates data as spectral curves or features |
| Linear analog-to-digital conversion | Non-linear (square root) analog-to-digital conversion |
| Gain switch or multiple gains needed for full dynamic range | Larger dynamic range, Gain switch not needed |
| Cloud mask or filter needed to reduce data rate | Clouds (featureless regions) automatically reduce data rate |
| Ground uplinks required for operational mode control | Operational modes based on spectral signatures |
| "Flat fielding" done on ground | "Flat fielding" done after A/D conversion (may be done on sensor chip) |
| "Flat" spectral response | Blue scattered light compensation (K.M.) |
Data Transmission | |
| All raw data acquired by instrument is transmitted | All information acquired by instrument is transmitted |
| Fixed data volume per area covered | Data volume dependent on information in scene |
| Bytes per band | Spectral curve coefficients or
3D Hyperspectral Cube Real-Time compression |
| Individual scans - no compression | Full scenes - lossless or lossy compression |
| Store and dump to near-polar receiving stations | Continuous direct broadcast |
Data Storage | |
| Fixed data volume "scenes" | Data volume dependent on "scene" information content |
| Bytes per spectral histogram | Spectral curve coefficients (or other curve representation) |
| Bytes per pixel or per scan | Full scene compressed data (various optional compression schemes) |
| Centralized processing and storage | Distributed reception, processing, and storage |
Data Utilization | |
| Modeling used to retrieve at-target reflectance | Empirical algorithms used to retrieve at-target reflectance |
| Data ordered from central facility | Data available via peer-to-peer network |
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