In-depth Analysis of Three Exposure Modes for Industrial Cameras: GS / RS / GRS-Knowledge Encyclopedia-Shenzhen Kai Mo Rui Electronic Technology Co. LTD

In-depth Analysis of Three Exposure Modes for Industrial Cameras: GS / RS / GRS

Source：Shenzhen Kai Mo Rui Electronic Technology Co. LTD2026-06-23

Overview of Three Exposure Modes for Industrial Cameras

This article elaborates on the operating mechanism, timing differences, pros & cons, applicable scenarios and parameter tuning essentials of three electronic exposure modes for comprehensive understanding.

1.Global Shutter (GS)

2.Rolling Shutter (RS)

3.Global Reset Shutter (GRS)

Global Shutter (GS)

Definition & Operating Principle

All pixels start and finish exposure simultaneously across the entire sensor array, followed by sequential or parallel pixel readout. Each frame forms a snapshot captured at the exact same instant. This architecture brings great advantages when synchronizing camera exposure with light source activation via hardware trigger, as exposure occurs uniformly across the whole sensor at once.

Engineering Implications

Motion robustness: Free from skew and rolling shutter distortion, ideal for online inspection scenarios including high-speed motion positioning, dimensional measurement, barcode & logistics sorting.
Readout, power consumption & cost: More complex pixel circuitry; typically inferior to same-generation Rolling Shutter sensors in read noise and maximum frame rate. For machine vision applications, this tradeoff delivers critical temporal consistency.

In GS timing sequence, all rows initiate and terminate exposure synchronously before readout starts, delivering even brightness distribution and minimal motion blur.

3.Rolling Shutter (RS)

Definition & Operating Principle

Exposure and readout are activated row by row sequentially. Each row maintains the identical configured exposure duration T, yet the start time of each row is offset by a row time t_row. This creates a time-skewed sampling window spanning the total frame scan time t_scan.

Engineering Advantages & Drawbacks：

Potential distortion: Skew, bending, jelly effect and other RS artifacts will emerge under high-speed motion or flickering illumination. The distortion becomes less noticeable with shorter row time, fewer total rows or smaller ROI (Region of Interest).
Strengths: Lower manufacturing cost under identical process node, with greater feasibility for high pixel density, superior sensitivity and higher frame rate. It is widely adopted in consumer devices and numerous industrial applications.

The sensor reads pixel data row by row during exposure, with readout propagating down sensor rows — hence the name Rolling Shutter. Reading one row consumes a fixed duration (e.g. 10 μs), known as row time, introducing a tiny time delay between consecutive rows.

For a rolling shutter sensor with 2048 rows (e.g. typical 2048×2048 CMOS sensor), the top row finishes readout at time 0, while the bottom row completes readout 2.048 ms later (10 μs × 2048 rows), defined as frame time. This cumulative time offset becomes prominent on large-format sensors and must be considered when imaging ultra-fast moving objects.

Global Reset Shutter (GRS)

Definition & Operating Principle

All rows start exposure simultaneously via global reset, yet exposure termination and pixel readout still proceed row by row in rolling fashion. This design drastically mitigates geometric distortion inherent to standard Rolling Shutter.

Side Effects & Countermeasures

Since bottom rows finish exposure later, exposure duration gradually increases from top to bottom within one frame, resulting in vertical brightness gradient (shading).
Flicker/pulsed light matching: Restrict illumination to the overlapping interval where all rows are accumulating charge to eliminate brightness gradient, achieving near-global-shutter performance (some manufacturers name this pseudo global reset release mode).

Many industrial camera models offer a combined Rolling + Global Reset operating mode with dedicated trigger pins for strobe synchronization.

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