private static char recLetter(int[][] pixels, int leftCol, int rightCol, char expChar) {
        
        int[][] matrix = new int[LETTER_HEIGHT][LETTER_WIDTH];
        for (int row = 0; row < pixels.length; row++) {
            for (int col = leftCol; col < rightCol; col++) {
                if(pixels[row][col] > 0) {
                    matrix[row][col - leftCol] = pixels[row][col];
                }
            }
        }
        
        int maxMatchCount = 0;
        int maxMatchIndex = -1;
        for (int i = 0; i < models.length; i++) {
            
            int matchCount = 0;
            for (int row = 0; row < matrix.length; row++) {
                for (int col = 0; col < matrix[row].length; col++) {
                    if(models[i][row][col] == matrix[row][col]) {
                        matchCount ++;
                    } else {
                        //matchCount --;
                    }
                }
            }
            
            if(matchCount > maxMatchCount) {
                maxMatchCount = matchCount;
                maxMatchIndex = i;
            }
        }
        
        if(maxMatchIndex < 10) {
            return (char)('0' + maxMatchIndex);
        } else {
            return (char)('A' + maxMatchIndex - 10);
        }
    }