检查验证码图片是否能分成4个部分，如果可以就检查4个字符在特征库中是否已经存在，如果不存在，就添加到特征库中，并暂时将对应的字符置为空格以待人工识别-Check whether the verification code image is divided into four parts, to check if 4 characters in the feature database already exists, and if not, to add to the features of the library and the corresponding characters in the temporary space to be manually set to Identification