[ros-users] accelerometer and tilt support + depth function

[Huan Liu]

you got a kinect?!

On Tue, Nov 16, 2010 at 11:49 AM, garratt <garrattgallagher at gmail.com> wrote:
> Has anyone gotten the accelerometer to work for the Kinect?
> Stéphane, I have your code (referenced below) with the accelerometer
> support, but libusb_control_transfer segfaults whenever I run acc_get.
>
> I noticed that Oliver Kreylos's code calls read control with the
> following parameters:
>
>  dataSize=readControl(0x40,0x32,0x0000,0x0000,data,sizeof(data));
>
> instead of:
> libusb_control_transfer(kinect_acc_tilt_dev, 0xC0, 0x32, 0x0, 0x0, buf,
> 8, 0)
>
> but everything still segfaults when I tried to match those parameters.
>
> If anyone has had success with this, I would love to hear about it!
>
> thanks
> Garratt
>
>
> On Mon, 2010-11-15 at 18:10 +0100, Stéphane Magnenat wrote:
>> Hello,
>>
>> I have integrated the accelerometer and tilt support from adafruit [1]
>> into my kinect node. To do so, I have added them to libfreenect, for
>> which I now provide a git with my changes instead of patches in my
>> kinect node [3].
>>
>> Here at ASL, Deon Sabatta and Davide Scaramuzza have found a more
>> precise depth function than 1/x. It is the following:
>>
>>       depth = k3 * tan(pixVal/k2 + k1)
>>
>> where
>>
>>       k1 = 1.1863
>>       k2 = 2842.5
>>       k3 = 0.1236
>>
>> "The k2 value is very sensitive and may require more/better
>> measurements; however, this is a pretty good approximation for the moment."
>>
>> I would like to raise two questions:
>>
>> 1. Having multiple implementations of Kinect ROS nodes is not harmful as
>> we happily share code. However, to ease the end-user's life I think that
>> we should agree on a naming convention for node and topic naming. Here
>> is a first suggestion:
>>    node name: "kinect"
>>    point cloud frame: "/kinect"
>>    point could topic: "/kinect/cloud" (PointCloud + color in "rgb")
>>    rgb image topic: "/kinect/image" (Image, rgb)
>>    depth (raw in 8bpp) image topic: "/kinect/depth_image" (Image, mono8)
>>    accelerometer topic: "/kinect/acc" (Vector3)
>>    tilt input: "/kinect/tilt" (Int16)
>> Feel free to discuss it and propose more conventions, for instance for
>> the params/etc.
>>
>> 2. I have branched libfreenect to provide updates more easily to the ROS
>> community, but I do not want to fork it. Hector, your input is warmly
>> welcome on my changes. Currently, libfreenect is not reentrant and does
>> not have clean naming prefixes. The reentrance might require a bit of
>> thinking, but the naming is straightforward; do you agree if I put a
>> heading kinect_ before all public functions?
>>
>> I'm looking forward to hearing your comments, dear kinect hackers.
>>
>> Kind regards,
>>
>> Stéphane
>>
>> [1] https://github.com/adafruit/Kinect
>> [2] https://github.com/ethz-asl/ros-drivers/tree/master/microsoft_kinect/
>> [3] https://github.com/stephanemagnenat/libfreenect
>>
>
>
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