@@ -8,39 +8,39 @@ The basic prototype is already working.
## Position detection ##
Therefore our current research focuses on automatic position detection. It is planned as a sequence of three stages.
### Sansa ###
First detector approximately locates the board in the picture. It uses SSD (single shot detector) with MobileNet and is working decently.
Examples (downloaded from Flickr under CC0 license):
Examples (downloaded from Flickr under CC0 license):
### Dochi ###
Then the cropped and normed image is fed to the second detector, designed to return precise grid corners' coordinates. This is currently implemented by a convolutional neural network and obtaining the required precision is a major hurdle to be passed.
Pretty good:
Pretty good:
Also good, but not enough:
Also good, but not enough:
### Genjo ###
With grid corners it is not difficult to rectify the image and cut it into tiles, one for each intersection. Then a third stage, Genjo classifier, decides whether the intersection is empty or occupied by a black or white stone. This is currently realized by a sample of pixels voting according to their HSI intensity and it suffices to produce satisfying results. Further improvements should be relatively easy.
## Stringing a sequence of board states to a sequence of moves ##
Base case: we have two correctly recognized positions differing by a single move (single added stone). Easy.
Issues:
* illegal positions → ignorable
* illegal positions -> ignorable
* positions unreachable from the previous state
* reachable from any past state. (Incorrect states inbetween.) How to pick the correct leaf of such a tree?
* reachable by more than one move. (Lost states inbetween.) Issues with branching factor.
* stone shifts
* stone stops being recognized → fixable manually and even ignorable
* stone stops being recognized -> fixable manually and even ignorable
* stone is recognized at an empty intersection. It can be occupied later for real. What do?
This is handled by the `statebag` package and its documentation also states the problem and used solution in precise terms.