Dataset Description
Over the period of November 2016 to March 3017, samples of surface condition of some pathways were collected from 10 different locations within Malaysia (in which over 100 were selected and released here). The sampling method employed was a judgmental sampling, which is a non-probability method based on judgement that certain areas could have more samples as compared to others. The following figure indicates (red dots) the locations of data being collected.
Data were collected during sunny days under direct sunlight or indirect sunlight based on the locations. The recording tasks were performed under natural (uncontrolled) environment hence some data might contain passers-by or vehicles.
Useful details about the dataset and hardware specifications of the stereo camera used to record the dataset.
To maintain the best quality of the images, the camera was set to capture and save the raw images without any compression (in bitmap file format). The image resolution was set to the highest as possible as allowed by the camera module, which is 752 x 480 pixels in width and height. The colour mode of the camera is monochrome only without other choices. A frame rate of 30 frames per second was used.
A summary of the image sequence parameters.
| Specification | Value |
| Image file format | Bitmap (BMP) |
| Image resolution | 752 x 480 pixels |
| Colour mode | Monochrome |
| Frame rate | 30 fps |
| Pixel format | 8-bit integer (0 – 255) |
The sensor used in video (image sequences) data collection was a DUO-MLX stereo camera with the following specifications.
Specifications of the Stereo Camera (based on details from the manufacture, Code Laboratory Inc.)
| Model | DUO-MINILX-LV1 (DUO MLX R2) |
| Baseline | 30.0 mm |
| Frame Rates | 0.1 – 3000+ FPS |
| Stereo Resolutions | Configurable Binning / Windowing:
– 45 FPS @ 752×480 – 49 FPS @ 640×480 – 98 FPS @ 640×240 – 192 FPS @ 640×120 – 86 FPS @ 320×480 – 168 FPS @ 320×240 – 320 FPS @ 320×120 |
| Pixel Size | 6.0 x 6.0 μm |
| Shutter Speed | 0.3 μsec ~ 10 sec |
| Lens Mount | Standard M8 x P0.5 |
| Field of View | 170° Wide Angle Lens
Low Distortion < 3% |
| Focal Length | 2.0mm – 2.1mm |
| Filters | 850-870nm Narrow Band-Pass |
| Illumination | Fully Programmable LED Array
3 Independently controlled 3.4W 850nm IR LEDs 170° light cone |
| Illumination Control | Individual brightness sequence programmable in 256 linear steps |
| Motion Sensing | 100Hz Sampling Rate
Six Degree of Freedom (DoF) Accelerometer/Gyroscope IMU/Temperature |
| Colour Modes | Monochrome (S/N Ratio > 54dB Linear) |
| Control Functions | Exposure/Shutter/Brightness |
| Scanning Modes | Progressive Scan/Global Shutter |
| Power Consumption | ~2.5 Watt @ +5V DC from USB |
| Interface | 480 Mbps – USB 2.0 Interface (Micro USB) |
| Weight | 12.5g |
| Operating Systems | DUO OS -Custom Linux Kernel, Linux, Mac OS or Windows |
| Operating Temperature | 0° to 40-50° C (32° to 104-122° F) |
| Storage Temperature | -20° to 45° C (-4° to 113° F) |
| Relative Humidity | 0% to 90% non-condensing |
The following figures depict the angle setting of the camera with 35 degrees off the chest at about 125cm from ground of the bearer.
Surface Discontinuity Dataset 