private int validateFailImage(int ans, int full_bg_index,
			int img_grp_index) {
		final int thread = 3;// 容差值

		String full_bg_name = md5Encode(full_bg_index + "").substring(0, 9);
		String bg_name = md5Encode(img_grp_index + "").substring(10, 19);

		String answer_decode = "";

		// 通过两个字符串奇数和偶数位拼接产生答案位
		for (int i = 0; i < 9; i++) {
			if (i % 2 == 0) {
				answer_decode += full_bg_name.charAt(i);
			} else if (i % 2 == 1) {
				answer_decode += bg_name.charAt(i);
			} else {
				gtlog("exception");
			}
		}

		String x_decode = answer_decode.substring(4, answer_decode.length());

		int x_int = Integer.valueOf(x_decode, 16);// 16 to 10

		int result = x_int % 200;
		if (result < 40) {
			result = 40;
		}

		if (Math.abs(ans - result) <= thread) {
			return 1;
		} else {
			return 0;
		}
	}