Single pixel imaging vs. pushbroom vs. snapshot: which hyperspectral technology should you choose?
Hyperspectral cameras are built around three broadly different acquisition strategies. Each makes a different trade-off between spatial resolution, spectral resolution, acquisition speed, tolerance to motion, and cost. Understanding these trade-offs matters more than any single spec sheet number when choosing a sensor for a real application.
Pushbroom (line-scan) hyperspectral imaging
A pushbroom, or line-scan, hyperspectral camera captures one spatial line of the scene at a time, dispersed into its full spectrum by a diffraction grating, and builds the complete 2D hyperspectral cube line by line as the camera or the scene moves beneath it. Pushbroom sensors deliver high spatial and spectral resolution and are the standard choice for airborne, drone-based and conveyor-belt inspection systems where motion is controlled and predictable. Their main constraint is exactly that requirement: the scene and the sensor must move relative to each other at a known, steady rate, which makes pushbroom a poor fit for static or unpredictably moving scenes.
Snapshot hyperspectral imaging
A snapshot hyperspectral camera captures the full spatial scene and a set of spectral bands in a single exposure, typically using a mosaic of spectral filters bonded directly onto the sensor array, similar in principle to the Bayer filter on an RGB camera. This makes snapshot cameras well suited to fast or unpredictable motion, since there is no scanning step. The trade-off is a fixed, usually modest number of spectral bands, set by the filter mosaic at manufacturing time, and a spatial resolution that is divided between the sensor’s pixels and the number of spectral bands captured.
Single pixel (compressive) hyperspectral imaging
Single pixel, or compressive, hyperspectral imaging takes yet another approach: it replaces the detector array entirely with a single spectrometer and a spatial light modulator, typically a video projector, that projects a sequence of structured patterns onto the static scene. Because a spectrometer natively measures hundreds of spectral bands at high resolution, the reconstructed hyperspectral cube can have very fine spectral resolution at a fraction of the hardware cost of an array-based sensor. It trades acquisition speed, since multiple projections are required per image, for spectral richness and low cost, which makes it a strong fit for lab, fablab and static field measurements rather than high-speed scanning.
At a glance
| Pushbroom | Snapshot | Single pixel (ONE-PIX / PRO-PIX) | |
|---|---|---|---|
| Spatial resolution | High | Medium, traded off with band count | Configurable, tied to projector resolution |
| Spectral resolution | High | Low to medium, fixed by filter mosaic | Very high, native spectrometer resolution |
| Acquisition speed | Fast, needs relative motion | Fastest, single exposure | Slower, multiple projections per image |
| Best suited to | Airborne, drone, conveyor-belt scanning | Fast or unpredictable motion, real time | Static or quasi-static scenes, lab and field spot measurements |
| Typical hardware cost | High | High | Low to moderate |
Which one should you choose?
If your scene moves past the sensor at a known, controlled speed, pushbroom is usually the right choice. If you need to capture fast or unpredictable motion in a single exposure and can accept fewer spectral bands, snapshot is the better fit. If your priority is fine spectral resolution and low hardware cost on scenes that can be measured while static, whether in a lab, a fablab or a fixed field station, single pixel compressive imaging, the approach behind ONE-PIX and PRO-PIX, is designed for exactly that case.