Multispectral Scanner (MSS) – Correct functional block sequence A typical whiskbroom MSS includes these functional blocks: 1) Video processor, 2) Dispersive system, 3) Detector, 4) Signal conditioner, 5) Collecting optics. What is the correct sequence through which incoming radiation passes and signals are processed?

Introduction / Context:
Multispectral scanners separate incoming radiance into spectral bands and convert it to electrical signals for recording. Knowing the physical and signal-processing order helps diagnose artefacts and understand calibration steps in Level-0/Level-1 data.

Given Data / Assumptions:

• Block names: collecting optics, dispersive element, detector, signal conditioning, and video processing.
• Whiskbroom (across-track) MSS architecture.

Concept / Approach:
The optical train first collects and focuses light, then disperses it spectrally. Detectors convert band-isolated photons to electrical signals. Signal conditioning (gain, filtering, multiplexing) prepares the data stream for digitization/formatting by the video processor.

Step-by-Step Solution:
Collecting optics (5): gather/focus scene radiance.Dispersive system (2): prism/grating splits into bands.Detector (3): band-specific photodetection to electrical signal.Signal conditioner (4): amplification, filtering, A/D interfacing.Video processor (1): timing, formatting, and output stream generation.

Verification / Alternative check:
Instrument handbooks and block diagrams consistently show optics → dispersion → detection → conditioning → formatting/recording.

Why Other Options Are Wrong:

• (a), (d): start with processing blocks before optics; physically impossible.
• (b), (c): misplace video processing before signal conditioning or disorder the optical path.

Common Pitfalls:
Confusing dispersive optics with filters placed after detection; in many MSS designs, spectral separation precedes detection.

Final Answer:
5, 2, 3, 4, 1