I am using Kinect v1 and I want to get the depth image in greyscale mode from the channel "/camera/depth_registered/image" in ROS. As I found here, I can do it by using the function imgmsg_to_cv2. The default desired_encoding for my depth messages is "32FC1", which I keep. The problem is that when I use the cv2.imshow() function to show it, I get the image in binary... When I do the same for the RGB image everything is being shown just fine...
Any help appreciated!
So after all, I found a solution, which you can see here:
def Depthcallback(self,msg_depth): # TODO still too noisy!
try:
# The depth image is a single-channel float32 image
# the values is the distance in mm in z axis
cv_image = self.bridge.imgmsg_to_cv2(msg_depth, "32FC1")
# Convert the depth image to a Numpy array since most cv2 functions
# require Numpy arrays.
cv_image_array = np.array(cv_image, dtype = np.dtype('f8'))
# Normalize the depth image to fall between 0 (black) and 1 (white)
# http://docs.ros.org/electric/api/rosbag_video/html/bag__to__video_8cpp_source.html lines 95-125
cv_image_norm = cv2.normalize(cv_image_array, cv_image_array, 0, 1, cv2.NORM_MINMAX)
# Resize to the desired size
cv_image_resized = cv2.resize(cv_image_norm, self.desired_shape, interpolation = cv2.INTER_CUBIC)
self.depthimg = cv_image_resized
cv2.imshow("Image from my node", self.depthimg)
cv2.waitKey(1)
except CvBridgeError as e:
print(e)
However, the result is not that perfect as the one I get from the image_view node of ROS, but it is still pretty acceptable!