ROS grayscale display

Open ROS environment:
```
roscore&
```
Enter the folder where ros package is located to initialize the environment variables:
```
source ./devel/setup.bash
```
Run the launch file:
```
roslaunch dmcam_ros start.launch
```

Show grayscale command:

rosrun image_view image_view image:=/smarttof/image_gray

The grayscale image is shown below：