Reliable warehouse obstacle detection requires more than distance measurement. Mobile robots must detect objects with different heights, shapes, colours, textures, and reflectivity under changing lighting conditions.
MRDVS S-Series depth cameras use direct time-of-flight (dToF) sensing to generate 3D depth information for AGV forklifts and AMRs. In a July 2026 performance test, MRDVS evaluated how the S11 handled black, reflective, overlapping, and strongly backlight targets.
Why Is Warehouse Obstacle Detection Difficult?
Detecting obstacles reliably in a working warehouse is not simply a matter of measuring distance.
Warehouse loads are rarely uniform. Pallets, cages, and stock may be matte black, wrapped in reflective film, or worn to a texture-less grey. Any of these surfaces can challenge a sensor tuned on a laboratory test target.
The working environment introduces additional variables:
- Aisles change after each restock.
- Direct sunlight may enter loading bays at certain times of day.
- Loads can overlap or partially block one another.
- AGVs and AMRs must detect obstacles while moving.
- A blind spot that appears only under certain lighting conditions can still create an operational risk.
The practical requirement is therefore not only to measure distance, but also to produce usable 3D information across changing targets and environmental conditions.
How Does dToF Depth Sensing Work?
Direct time-of-flight technology emits ultra-short pulses of infrared light—typically on a nanosecond scale—and records the interval (Δt) between emission and the return of the reflected signal. Distance is derived directly:
Because the measurement is a direct timing of the returned pulse, each pixel within the field of view can return a depth value largely independently of the target’s colour or texture. Active stereo, by contrast, projects a pattern and triangulates depth from how that pattern deforms across two lenses—a process that depends on having sufficient visual information for feature matching.
The S-Series implements this principle with three hardware choices that matter in the field:
- Sub-nanosecond ranging core: A high-resolution Time-to-Digital Converter (TDC) and precision delay line design minimise time-domain quantisation error, supporting stable ranging accuracy under dynamic operation.
- Back-illuminated SPAD sensor: High photon sensitivity supports detection on low-reflectance surfaces, including black objects, and under challenging light.
- High-PCE 940 nm VCSEL: High peak optical power at low energy consumption and minimal thermal drift, for consistent output over long operating periods.
MRDVS attributes the results observed in the tests below to this underlying sensing method.
What Did the Test Evaluate?
Camera used during the test:
- An MRDVS S11 dToF depth camera
The test programme examined four types of targets and scenes:
- Black objects positioned close to a white wall
- A reflective column
- Multiple stacked indoor objects at different depths
- Four objects against a strong backlight
The test focused on depth-image completeness, edge definition, behaviour around overlapping objects, missing point-cloud data, and noise.
Test 1: Black Objects Against a White Wall

The first test placed a black object close to a white wall.
This is a simple but revealing scene because the camera must distinguish two neighbouring surfaces using their depth difference alone, even though the black object provides limited visual texture.
The results show that the S11 produced a complete depth image, which was then transformed into a 3D point cloud image with clearly defined edges separating the objects from the wall. As shown above.
Test 2: Reflective Column

The second test evaluated a reflective column.
MRDVS reports that the S11 produced a complete depth image, which was then transformed into a point cloud image without missing or dispersed data around the edges of the column.
This test was intended to examine how the dToF camera handled a target that could produce challenging reflections—a common condition where loads are shrink-wrapped or stored in metal cages.
Test 3: Overlapping Objects at Different Depths

The third test used an indoor scene containing multiple stacked objects positioned at different depths.
MRDVS reports that the S11 retained detail throughout the scene.
For warehouse obstacle detection, retaining depth information around overlapping objects is relevant because pallets, loads, racks, and mobile equipment may partially block one another. A gap in the point cloud at an overlap boundary is precisely where a robot needs data to decide whether a gap is traversable.
Test 4: Direct Light

The fourth test isolated the lighting variable. Four normal-reflectance objects were positioned behind a strong light source aimed toward the camera and approximately 4 m from it, so that the illumination fell on the lens rather than on the targets.
Backlighting of this kind reproduces one of the most common causes of depth failure in real deployments. An AGV forklift crossing a bay door moves from roughly 200 lux indoors to tens of thousands of lux outdoors within a single vehicle length, often facing directly into the light as it does so, and the sensor has no opportunity to be re-tuned between the two conditions.
MRDVS reports that under these conditions the S11 produced a complete depth image across the full field of view, which was then transformed into 3D poinst cloud image with all four objects clearly separated from one another and from the background.
Test Results at a Glance
| Test Scene | MRDVS S11 (dToF) |
| Black objects close to a white wall | Complete point cloud image with well-defined separation between the surfaces |
| Reflective column | Complete point cloud image without missing or dispersed edge data |
| Stacked objects at different depths | Detail retained throughout the scene |
| Four objects against a strong backlight | Complete point cloud image, with all four objects clearly separated |
Reported Latency and Minimum Working Distance
Detection quality only translates into safety if the result reaches the vehicle controller in time.
MRDVS reports typical end-to-end latency of 70 to 100 milliseconds for the S11 under standard operating conditions, and a minimum working distance of approximately 10 cm (4 in).
The minimum working distance is relevant when obstacles need to be detected close to the path of an AGV forklift—for example, a pallet foot or a kerb immediately ahead of the forks. Actual deployment performance also depends on sensor placement, vehicle geometry, detection-zone configuration, and operating speed.
From Depth Data to Vehicle Action: Built-In Obstacle Avoidance
Obstacle detection is only one part of a complete mobile-robot safety and control system. The S-Series ships with a real-time obstacle avoidance algorithm that runs directly on the camera, with no external industrial PC required.
Highlights of the Built-In Obstacle Avoidance Solution
- Three-Tier Safety Distances: Set exact Warning (slow-down), Alarm (full stop), and Shielding (ignore) zones anywhere along the robot’s path, so the vehicle can decelerate before it has to stop.
- Up to 20 Pre-Defined Zones: Users can switch between zones dynamically via API as the AMR moves, allowing context-aware safety policies across different areas of operation—a narrow aisle and an open staging area do not need the same profile.
- Adjustable Detection Field: Define the horizontal coverage (left and right boundaries) and the vertical detection range (upper and lower height limits) to match your specific environment and obstacle profiles.
- Vehicle-Referenced Coordinates: The raw point cloud is transformed into the vehicle’s coordinate system using calibrated extrinsic parameters. The detection zone therefore stays fixed relative to the AGV or AMR, regardless of where the camera is mounted on the chassis.
- Clear Output Signals: The system outputs intuitive status codes (0 / 1 / 2) corresponding to Clear, Warning, or Alarm states over Ethernet or customisable I/O, enabling straightforward integration with an existing robot control system.
Because the zone geometry can be configured as a rectangular or cone-shaped volume, the detection area can follow the vehicle’s direction of travel instead of relying on a single fixed sensing radius.
Advanced Perception for Complex Operational Scenarios
Beyond core zone-based avoidance, the S-Series supports higher-tier perception for cluttered and collaborative environments.
- Multi-Object Analysis: Accurately measures the distance between adjacent obstacles and outputs structured data, enabling intelligent path planning and navigation in cluttered environments rather than a simple stop-or-go decision.
- AI Person Detection: A dedicated algorithm reliably distinguishes humans from inanimate objects, allowing heightened safety protocols to be applied in collaborative workspaces.
- Multi-Camera Synchronisation: Designed for sites where multiple AMRs operate simultaneously, the S-Series keeps cameras across the fleet synchronised and interference-free, preventing cross-talk and data collision in busy warehouses.
- High-Fidelity RGB-D Streams: Synchronised, calibrated RGB and depth data give developers reliable raw material for building their own semantic understanding algorithms, such as object classification and scene segmentation.
- Tailored Development Services: MRDVS provides full-cycle custom algorithm development, including custom object recognition and segmentation, specialised scene-understanding logic, and customised I/O and data output configurations.
Conclusion
Warehouse obstacle detection must account for more than distance. Target colour, texture, reflectivity, overlap, lighting, sensor placement, and vehicle movement all affect the depth information available to an AGV or AMR.
The July 2026 test described here shows how the MRDVS S11 handled four deliberately difficult scenes—black objects against a white wall, a reflective column, overlapping stacked loads, and four objects against a strong backlight. Across all four scenes the S11 returned complete depth images with clearly defined edges.


