neiyou_user_web/config/captcha.php

<?php

return [
    'characters' => [
        '2',
        '3',
        '4',
        '6',
        '7',
        '8',
        '9',
        'a',
        'b',
        'c',
        'd',
        'e',
        'f',
        'g',
        'h',
        'j',
        'm',
        'n',
        'p',
        'q',
        'r',
        't',
        'u',
        'x',
        'y',
        'z',
        'A',
        'B',
        'C',
        'D',
        'E',
        'F',
        'G',
        'H',
        'J',
        'M',
        'N',
        'P',
        'Q',
        'R',
        'T',
        'U',
        'X',
        'Y',
        'Z',
    ],
    'default'    => [
        'length'  => 4,
        'width'   => 120,
        'height'  => 36,
        'quality' => 90,
        'math'    => false,
        'expire'  => 60,
    ],
    'math'       => [
        'length'  => 9,
        'width'   => 120,
        'height'  => 36,
        'quality' => 90,
        'math'    => true,
    ],

    'flat'    => [
        'length'     => 6,
        'width'      => 160,
        'height'     => 46,
        'quality'    => 90,
        'lines'      => 6,
        'bgImage'    => false,
        'bgColor'    => '#ecf2f4',
        'fontColors' => [
            '#2c3e50',
            '#c0392b',
            '#16a085',
            '#c0392b',
            '#8e44ad',
            '#303f9f',
            '#f57c00',
            '#795548',
        ],
        'contrast'   => -5,
    ],
    'mini'    => [
        'length' => 3,
        'width'  => 60,
        'height' => 32,
    ],
    'inverse' => [
        'length'    => 5,
        'width'     => 120,
        'height'    => 36,
        'quality'   => 90,
        'sensitive' => true,
        'angle'     => 12,
        'sharpen'   => 10,
        'blur'      => 2,
        'invert'    => true,
        'contrast'  => -5,
    ],
];