Roktrack can basically mow the weed with just a pylon(traffic cone). However, if the pylon happens to be on the neighbor's house, or if a truck happens to be passing by with a pylon on it, the mower will head in that direction. Digit OCR was designed to address these issues. To achieve this additional functionality, all that is needed is to attach a piece of paper with a single digit number printed on it to the pylon. The robot identifies individual pylons by recognizing this number. This means that it can select the pylon it should aim for among the pylons in its field of vision. This inhibits unexpected movements.

Why OCR? Generally, AR markers and QR codes are used for robotic applications. To use these, it is important to be able to detect edges. However, in reality, the edges of markers are blurred when trying to detect them from a distance of 10m or more. I have come to the conclusion that it is difficult to identify a marker from a distance of more than 10 meters with a wide-angle camera. In order to detect objects with blurred details, object detection, which can use more ambiguous features, was suitable. In order to increase the detection distance and speed up the processing, the following is processed.

The image is captured by the camera at the highest resolution. The resolution of that image is then reduced to perform inference in the pylon model. The detection content is normalized and the corresponding portion of the original highest resolution is extracted. The extracted part is then inferred by the Digit OCR model with a resolution of 96*96 to identify what numbers are pasted on the pylon. And since the existing OCR model for transcribing text takes several seconds to infer, I created a very simple custom model that can collect images of numbers and detect only the digits 0-9.

Reference

AR Marker shot from 10m away

AR Marker shot from 20m away

AR Marker shot from 30m away

This would make edge detection impossible, so AR markers would be limited to detection at a maximum of 10m

"8" taken from 30 meters away

For simple numbers, object detection can detect objects as far as 30 meters away. If the resolution can be increased to FullHD, 2K, 4K, and 8K, it will be possible to identify individuals at even greater distances. (This is if the data can be transmitted from the camera to the computer without delay.)