NAO fails to save captured image to local computer

Question

I'm trying to save a captured 640x480 RGB image with NAO's front camera to my computer. I'm using python and PIL to do so. Unfortunately, the image just won't save on my computer, no matter what image type or path I use for the parameters of the Image.save()- Method. the image created with PIL contains valid RGB-information though. Here's my code sample from choregraphe:

import Image

def onInput_onStart(self):
    cam_input = ALProxy("ALVideoDevice")
    nameId = cam_input.subscribeCamera("Test_Cam", 1, 2, 13, 20)

    image = cam_input.getImageRemote(nameId) #captures an image
    w = image[0] #get the image width
    h = image[1] #get the image height
    pixel_array = image[6] #contains the image data

    result = Image.fromstring("RGB", (w, h), pixel_array)
    #the following line doesnt work
    result.save("C:\Users\Claudia\Desktop\NAO\Bilder\test.png", "PNG")

    cam_input.releaseImage(nameId)
    cam_input.unsubscribe(nameId)
    pass

Thank you so much for your help in advance! - a frustrated student

Answer 1

In the comment, you say the code is pasted from choregraphe, so I guess you launch it using choregraphe. If so, then the code is injected into your robot then started.

So your image is saved to the NAO hard drive and I guess your robot doesn't have a folder named: "C:\Users\Claudia\Desktop\NAO\Bilder\test.png".

So change the path to "/home/nao/test.png", start your code, then log into your NAO using putty or browse folder using winscp (as it looks like you're using windows).

And you should see your image-file.

Answer 2

In order for your code to run correctly it needs to be properly indented. Your code should look like this:

import Image

def onInput_onStart(self):
    cam_input = ALProxy("ALVideoDevice")
    nameId = cam_input.subscribeCamera("Test_Cam", 1, 2, 13, 20)

    image = cam_input.getImageRemote(nameId) #captures an image
    w = image[0] #get the image width
    h = image[1] #get the image height
    pixel_array = image[6] #contains the image data

    ...

Make sure to indent everything that's inside the def onInput_onStart(self): method.

Answer 3

Sorry for the late response, but it maybe helpful for someone. You should try it with naoqi. Here is the documentation for retriving images http://doc.aldebaran.com/2-4/dev/python/examples/vision/get_image.html

The original code was not working for me so I made some tweeks.

parser = argparse.ArgumentParser()
parser.add_argument("--ip", type=str, default="nao.local.",
                    help="Robot IP address. On robot or Local Naoqi: use 
                    'nao.local.'.")
parser.add_argument("--port", type=int, default=9559,
                    help="Naoqi port number")
args = parser.parse_args()
session = qi.Session()
try:
    session.connect("tcp://" + args.ip + ":" + str(args.port))
except RuntimeError:
    pass
"""
First get an image, then show it on the screen with PIL.
"""
# Get the service ALVideoDevice.
video_service = session.service("ALVideoDevice")
resolution = 2    # VGA
colorSpace = 11   # RGB
videoClient = video_service.subscribe("python_client",0,3,13,1)
t0 = time.time()
# Get a camera image.
# image[6] contains the image data passed as an array of ASCII chars.
naoImage = video_service.getImageRemote(videoClient)
t1 = time.time()
# Time the image transfer.
print ("acquisition delay ", t1 - t0)
#video_service.unsubscribe(videoClient)

# Now we work with the image returned and save it as a PNG  using ImageDraw
# package.
# Get the image size and pixel array.
imageWidth = naoImage[0]
imageHeight = naoImage[1]
array = naoImage[6]
image_string = str(bytearray(array))
# Create a PIL Image from our pixel array.
im = Image.fromstring("RGB", (imageWidth, imageHeight), image_string)
# Save the image.
im.save("C:\\Users\\Lenovo\\Desktop\\PROJEKTI\\python2- 
        connect4\\camImage.png", "PNG")

Be careful to use Python 2.7. The code runs on your computer not the NAO robot!