Describe the current behavior / 问题描述 (Mandatory / 必填)

Environment / 环境信息 (Mandatory / 必填)

• Hardware Environment(Ascend/GPU/CPU) / 硬件环境:

Please delete the backend not involved / 请删除不涉及的后端:
/device ascend

• Software Environment / 软件环境 (Mandatory / 必填):
  -- MindSpore version (e.g.,r1.6 commit_id=xxxx) :r1.7 commit_id = ''[sha1]:26585b36,[branch]:(HEAD->master,origin/master,origin/HEAD)''
  -- Python version (e.g., Python 3.7.5) : Python 3.7.5
  -- OS platform and distribution (e.g., Linux Ubuntu 16.04):
  -- GCC/Compiler version (if compiled from source):

• Excute Mode / 执行模式 (Mandatory / 必填)(PyNative/Graph):

Please delete the mode not involved / 请删除不涉及的模式:
/mode pynative
/mode graph

Related testcase / 关联用例 (Mandatory / 必填)

ocr_evaluate教程

Steps to reproduce the issue / 重现步骤 (Mandatory / 必填)

Describe the expected behavior / 预期结果 (Mandatory / 必填)

Related log / screenshot / 日志 / 截图 (Mandatory / 必填)

数据集中存在灰度图片，demo代码处理报错，代码的容错性需要提升。
ValueError: {'error': "Call Function 'perturbation.perturb' Failed, method: 'natural_perturbation', stage index(begin with 1): 1, error msg: OpenCV(3.4.9) /cache/opencv-python-31/opencv/modules/imgproc/src/color.sim...olicy)2; cv::InputArray = const cv::_InputArray&; cv::OutputArray = const cv::_OutputArray&]'\n> Invalid number of channels in input image:\n> 'VScn::contains(scn)'\n> where\n> 'scn' is 1\n"}

Special notes for this issue/备注 (Optional / 选填)