Examples

You will need stereo headphones to gain a better understanding of the observed phenomena.

The color markers in the image represent the part of the image that generated the echo sound that is being played at that moment.

The bottom graph in the image represents the amplitudes of the signal, as they change through time.

The beep with a different frequency at the beginning of each image signals the time when the virtual speaker in the camera would emit a sound.

The sound in the animations below is travelling very slowly so that the differences become apparent with no effort. In practice the slowdown does not have to be so large to make the differences observable.

The images in the animations below were created by aligning a video frame of the camera with a depth frame. As the field of view of the RGB sensor produving the video frames is smaller than the field of view of the depth sensor, there is a black area around the colored image that still produces echos. Some parts of the color images also have unusual black lines. These lines are an artifact of aligning video frames with depth frames and correspond to regions where the depth frame had no depth information. The depth vision camera is a stereo camera, and therefore close to sharp edges or corners the depth can not be accurately determined.

In all clips the camera is as if it were attached to a chest-mount camera holder, facing slightly downwards from the horizontal level.

Tree

The cameara moves from seeing the tree on the righ side of the frame, through a position where the tree is on the left side of the frame back to the starting side.

Tree on left side

One frame with the tree in the right half of the image.

Tree on right side

One frame with the tree in the left half of the image.

Stairs

Going up

At the beginning the stairs going up (5 stairs, about 1m high in total) are 3m in ahead of the camera in the center of the image. The clip ends a few steps after the stairs have been ascended, there is only flat surface after the stairs.

Going down

At the beginning the stairs going down (the same ones as in the previous clip) are about 2.5m ahead of the camera, slightly left from the center of the image. The clip ends with the camera approximately 2m away from the stairs, facing the opposite direction than the stairs.

Obstacle

Gate barrier

The video shows the case when the camera approaches a gate barrier. After the gate barrier, the camera looks at nearby obstacles.

Parked bicycles on our right

Bicycles are parked on the right side of the camera, when the camera moves pass the bicycles.

Flower pots and walking around bushes

Walking in a park, around some flower pots and bushes.