支持compressed image消息的kalibr，错误TypeError: Conversion is only valid for arrays with 1 or 2 dimensions

kalibr是标定camera和imu外参的重要工具，但是原配的只支持ros的image消息。这里通过修改源代码使其支持compressed image消息。

1. 搜索文件：ImageDatasetReader.py
2. 修改函数def getImage为:

3.     def getImage(self,idx):
           
           topic, data, stamp = self.bag._read_message(self.index[idx].position)
           ts = acv.Time( data.header.stamp.secs, data.header.stamp.nsecs )
           if data._type == 'mv_cameras/ImageSnappyMsg':
               if self.uncompress is None:
                   from snappy import uncompress
                   self.uncompress = uncompress
               img_data = np.reshape(self.uncompress(np.fromstring(data.data, dtype='uint8')),(data.height,data.width), order="C")
           elif data._type == 'sensor_msgs/CompressedImage':
               np_arr = np.fromstring(data.data, np.uint8)
               img_data_rgb = cv2.imdecode(np_arr, cv2.IMREAD_COLOR)
               img_data = cv2.cvtColor(img_data_rgb,cv2.COLOR_BGR2GRAY)
           else:
               img_data = np.array(self.CVB.imgmsg_to_cv2(data, "mono8"))
           return (ts, img_data)

    

4. 如果出现这个错误：TypeError: Conversion is only valid for arrays with 1 or 2 dimensions. Argument has 3 dimensions

5. 修改上面代码为：

       def getImage(self,idx):
           
           topic, data, stamp = self.bag._read_message(self.index[idx].position)
           ts = acv.Time( data.header.stamp.secs, data.header.stamp.nsecs )
           if data._type == 'mv_cameras/ImageSnappyMsg':
               if self.uncompress is None:
                   from snappy import uncompress
                   self.uncompress = uncompress
               img_data = np.reshape(self.uncompress(np.fromstring(data.data, dtype='uint8')),(data.height,data.width), order="C")
           elif data._type == 'sensor_msgs/CompressedImage':
               np_arr = np.fromstring(data.data, np.uint8)
               img_data_rgb = cv2.imdecode(np_arr, cv2.IMREAD_COLOR)
               img_data = cv2.cvtColor(img_data_rgb,cv2.COLOR_BGR2GRAY)
           else:
               img_data = np.array(self.CVB.imgmsg_to_cv2(data, "mono8"))
               img_data=np.squeeze(img_data)
           return (ts, img_data)