Summary

The data is recorded at night, with few street lights illuminating the scene. Our setup was mounted on top of a car which was driving through the streets of a city, collecting time-synchronized data at 2.2 FPS. It demonstrates a challenging condition due to significantly lower illuminance or lux. This require the cameras to capture images at enhanced exposures, while balancing the blur it introduces due to motion. The depth-maps reveal that our stereo-matching algorithm can identify features even in seemingly dark surfaces like the road, tree trunks, and curb.

The full data can be accessed here: AWS S3 link

Camera Specifications

Horizontal Field of View 30 degrees
Baseline 1.17 meters
Resolution 5.4 MP
Bit depth 16 bit
Frame rate 2.2 FPS

Topbot Images

These are vertically concatenated raw images from the left and right camera as shown below:

000000038.tiff

Camera Intrinsic Parameters

Assuming pin-hole model for the camera, we get the following intrinsics for our left camera (1) and right camera (2):

| i1_fx = 5276.69 i1_fy = 5276.61 i1_cx = 1453.21 i1_cy = 1005.95 i1_k1 = -0.200407 i1_k2 = 0.399375 i1_k3 = -0.975446 i1_k4 = 0 i1_k5 = 0 i1_k6 = 0 i1_p1 = 0.00343018 i1_p2 = -0.000560687 | i2_fx = 5283.89 i2_fy = 5282.77 i2_cx = 1398.11 i2_cy = 966.162 i2_k1 = -0.207581 i2_k2 = 0.534651 i2_k3 = -1.7257 i2_k4 = 0 i2_k5 = 0 i2_k6 = 0 i2_p1 = 0.00278165 i2_p2 = -0.000319389 | | --- | --- |

Extrinsic Parameters

We choose the center of the left rectified image as our frame of reference, where the z-axis faces in the forward direction and the y-axis points in the downward direction. Consequently, the right camera is located along the x-axis in our chosen frame of reference.

image.png

The translation (in m) and rotation (in degrees) for the right-camera w.r.t our frame of reference is shown below:

Tx = 1.1699 Ty = 0.0002 Tz = -0.0002 theta_x = 0.3436844382503575 theta_y = -0.07656089029470413 theta_z = 0.157368876500715

We follow the Z-Y-X Euler angle rotation convention. Consequently the overall rotation matrix can be established by: R = R_z * R_y * R_x.

Left-rectified Images

The left-rectified image shows the image from the left camera after rectification, as shown below:

000000038.tiff