ANIMATING CHESS MOVES RECORDED ON CHESS INFORMANT Süleyman Eken, Ahmet Sayar Department of Computer Engineering, Kocaeli University, Kocaeli, Turkey {[email protected], ahmet.sayar@ kocaeli.edu.tr } ABSTRACT including chess moves are darker than the other part of In this study, we focus on animating chess games image. So, we separate these portions from others and recorded on chess informant. This involves recognition then purpose of recognition of chess moves characters. of chess characters as well as moves and playing them Within this concept, interested problem is a kind of on chessboard. The proposed technique eliminates document image analysis problem. false recognitions by means of controlling possible Although chess game is very old, the game moves in accordance with the rules of chess continues to interest and is very popular mind-game in (semantics). The paper produces solution for figurine many countries [2], [3]. There are various notations for algebraic notation (FAN). For character and figure recording the number of chess moves and each country recognition, we form feature vector including area, has own markings for figures. With the development center of area, perimeter, thinness ratio, aspect ratio, of internet, it is critically important to transfer compactness, Euler number, and projection. In the recognition stage, multi-layer feed-forward (MLF) magazines and books including chess games to the neural network with back-propagation learning electronic environment. The descriptions of game are algorithm is utilized to recognize characters and not available in computer-readable. figures of chess by using this feature vector. The Text of Chess Informant series was set using 200 results show that the proposed system is capable of different letters. These series consist alphanumeric contributing to the generation of robust game fonts in both roman and boldface, chess characters, databases through digitizing of chess games recorded and a number of special symbols used for on chess informant. interpretation. Lines of text are set uninterrupted, in other words lines are spaced vertically as tightly as KEYWORDS possible for the point size. Also, quality of Informant‘s Chess readings; chess charactrer recognition; chess print is mostly worse than that seen in most modern notaions; document image analysis. books [4]. Some of the existing studies in the literature on the recognition of chess characters are as follows: Nabiyev 1 INTRODUCTION [5] initially represented chess readings turning several notations to common notation that is FAN. After the Nowadays, pattern recognition has been studied in chess readings analysis, the transformations of many fields including psychology, psychiatry, recognized chess characters have been performed. biometrics, bioinformatics and gene expression Chess moves have been animated on chessboard, so analysis, cognitive science, traffic flow, handwriting mistakes in recognition stage have been eliminated by recognition in criminology and banking, optical controlling possible moves in accordance with the character recognition (OCR), and computational rules of chess. For character recognition, he utilized finance and the stock market. OCR systems are the heuristic solution together with the figural divided into two categories: task-specific and general information relating to the notations. Baird and purpose systems. In task-specific systems, certain Tompson [4] proposed an empirical page reader portions of document are digitized by means of system performed top-down layout analysis -divide a specific equipments. Systems such as bank check document image into smaller regions- for readers, account processing systems, and airline identification of columns, lines, and characters through ticketing readers use task-specific OCR systems. In skew-estimation technique. By analyzing the formal general purpose OCR systems, the document is rules of chess, the error rate was minimized separated text and non-text blocks. Text blocks are considerably. Zhu and et al. [6] presented a Chinese separated to lines, words, and characters. These chessman pattern recognition system based on rate- systems are known as document image analysis [1]. In connectivity and concentric circle algorithms. Chess Informant- a series of volumes leading source of According to their experimental results, concentric games and analysis for serious chess players, portions circle algorithm is more suitable then rate-connectivity horizontal rows of squares labelled 1 through 8. The algorithm in terms of complexity and accuracy. files are known as the vertical columns of squares In this study, we propose a system extracting of labelled a through h. After the labelling, each square chess moves the Chess Informant and recognizing of on the chessboard can be described by a peerless file chess characters. In a Chess Informant, each game and rank combination. Excepting of Knight, all pieces consists of a move number and two ply (half-moves), are identified by a single capital letter starting with and each ply is described in three characters on their names, because the K letter is used for a King, so average (see Fig. 1). By applying knowledge of the the Knight is identified by an N (K-King, Q-Queen, R- rules of chess (semantics), each move is checked for Rook, B – Bishop, N-Knight). There is no piece legality. identifier for a Pawn. In this notation, firstly white moves are written and then black moves. Each full move is sequentially numbered. Many books and computer chess programs use FAN. This is as closely as normal algebraic notation except that identifiers of the piece are replaced with graphic symbols of the pieces. Here is an example of the same moves in some Figure 1: An example of text from the Chess Informant of the notations (see Table I). This study consists of following steps: (i) Table 1: Chess notation examples preprocessing on text of chess, (ii) extracting of chess # Algebraic FAN LAN Descriptive Coordinate games from the Chess Informant, (iii) recognizing of e4 e2-e4 P-K4 E2-E4 chess characters, and (iv) applying knowledge of the 1. e4 e5 rules of chess and checking for legality. The remainder e5 e7-e5 P-K4 E7-E5 of this paper is organized as follows. In Section II, Nf3 ♘f3 Ng1-f3 N-KB3 G1-F3 2. chess notations are presented for better understanding Nc6 ♞c6 Nb8-c6 N-QB3 B8-C6 of the subject. In Section III, extraction of portion of Bb5 ♗b5 Bf1-b5 B-N5 F1-B5 3. chess game from other part of paper is explained. a6 a6 a7-a6 P-QR3 A7-A6 Also, the methodology of the study and findings are Bxc6 ♗xc6 Bb5xc6 BxN B5-C6 presented in same chapter. Section IV draws a 4. conclusion and future works. dxc6 dxc6 d7xc6 QPxB D7-C6 d2-d3 d3 d3 P-Q3 D2-D3 5. Bf8- Bb4+ ♝b4+ B-N5ch F8-B4 2 CHESS NOTATIONS b4+ Nc3 ♘c3 Nb1-c3 N-B3 B1-C3 Chess notation is developed to save moves made 6. Nf6 ♞f6 Ng8-f6 N-B3 G8-F6 during a game of chess or the positions of the pieces. They will allow chess players to reconsider O-O O-O O-O O-O E1-G1 7. their games and read chess books. Many systems of Bxc3 ♝xc3 Bb4xc3 BxN B4-C3 chess notation are available today, three of them are common. These are descriptive (English notation), There are also the following notations: coordinate, and algebraic. Algebraic notation is the International Correspondence Chess Numeric Notation most commonly used in tournaments and in all modern (ICCF), Portable game notation (PGN), Forsyth– books. Also, it is sort of a hybrid notation between Edwards notation (FEN), and Extended position descriptive and coordinate. Detailed information about description (EPD) [7]. Different languages have algebraic notations is given as follows. different names for the pieces. FAN is independent of the language. 2.1 Algebraic Notations 2.2 Chess Symbols There are a number of different types of algebraic chess notations but popular types used today are Short Various symbols are usually found in chess books. The Algebraic Notation (SAN), Long Algebraic Notation following markings are usually used by commentators (LAN), and Figurine Algebraic Notation (FAN). to give evaluative comment on a move: Chessboard is divided into ranks and files in the algebraic notation. The ranks are known as the ! (a particularly good move) 3 EXTRACTION OF CHESS !! (an excellent move) GAMES AND MOVES ? (a bad move) ?? or ??? (a blunder) Characters in the Chess Informant must be recognized !? or * (an interesting move that may not be best) firstly, in order to interpret printed text. Character ?! (a dubious move - one which may turn out to be recognition process usually requires pretreatment. bad) Pretreatment consists of several steps such as TN or N (a theoretical novelty) converting gray level image, binarization, detection frame of characters, and scaling/normalization. In this These symbols indicate the strategic balance of the study, we focus on images with less noise and our game position: proposed technique produces solution for FAN. ∞ (Unclear): It is unclear who (if anyone) has an 3.1 Image Pre-treatment advantage =/∞ (Whoever is down in material has compensation Raw image is converted into grayscale for simplifying for the material) the tasks of the subsequent steps in the algorithm. As a = (Even position) result of converting gray-image, each pixel is +/= (White has slightly better chances) represented by 1 byte. =/+ (Black has slightly better chances) Median filtering is one kind of smoothing +/− or ± (White has much better chances) technique. Most smoothing techniques remove noise, −/+ or ∓ (Black has much better chances) but they blur edges. We utilize median filtering to +− (White has a clear advantage) reduce noise over image. Applying multiple median −+ (Black has a clear advantage) filters lessens noise and brightness. To avoid the computational expense, median filter was used with There are some other symbols used in multilingual small size (3x3) window [9]. The filter is considered publications: following 3x3 image window.