Kinect 3D outdoor: first test

It was a sunny September Sunday, so I decided to take a walk with my wife Kathi and show her one of the hermitages located in the valley in which we live (Val di Non, Trentino, Italy). 

My second thought was that the ramble was a perfect opportunity to test the hacked Kinect and try to document in 3D the main wall of S. Gallo's ruins (the remains of the hermitage). So I prepared the backpack with Kinect, the external battery and the rugged pc we normally use on the archaeological excavations. 

After half an hour's walk throught apple orchards and woods we reached the hermitage. Along the way we also found a stunned rooster. That was strange! A rooster, in italian "gallo", in the S. Gallo's hermitage...

However, we began to try to document the main wall of the ruins, which you can see in the picture below...

S. Gallo's hermitage, with the rooster

... but, probably due to direct sunlight conditions, Kinect and RGBDemo where not working propertly.

In fact, as you can also read in M. Dalla Mura, M. Aravecchia and M. Zanin poster (during "LOW COST 3D: sensori, algoritmi e applicazioni" workshop), "...The main issue is due to direct Sun illumination that leads to saturation in the depth acquisition...". Moreover the software (RGBDemo) was reacting very slowly, but this was probably due to the hardware (Panasonic Thougbook), which is less powerful compared to the laptop I normally use to work. Secondly also RGBDemo seems to work better on GNU/Linux (ArcheOS), the Operating System which runs my laptop, than in Windows, the rugged PC OS (but this could be just my impression). 

Not beeing satisfied with the results I get with the 3D documentation of the ruins (software too slow to manage all the data recording process, high errors on the sunny parts of the wall, etc...), I decided to check for another subject to document. Luckily in S. Gallo's hermitage are not missing the caves, so, with the help of Kathi, I did a fast digital 3D copy of the cave you see in the picture below.

S. Gallo's cave

This time the software was working good, fast enought to work on the field and with negligible errors in data acquiring. In the movie below it is possible to see the final pointcloud (not complete, but big enought to understand the quality of a 3D "field" documentation with Kinect).

After this test, our Kinect was ready to the "trial by fire" of a real (indoor) archaeological excavation, which will be the topic of one of the next posts in ATOR.

Ciao.

Kinect 3D outdoor: hacking the hardware

Some weeks ago I finally found the time to modify our Kinect in order to test it outdoor. 

My main problem was the power supply, while in an archaeological excavation it can be difficoult to find an access to electricity. The solution was obviously an external battery, but I did not know the right voltage and amperage. Finally I found this interesting post, in Ken Mankof blog, with all the necessary informations to hack Kinect for the fieldwork.

I tried to summarize all the operations I did in the image below:

The modified Kinect

As you can see, Kinect's main cable ends with an USB (for data transfer) and with an electric plug (for power supply). I cut the cable before the elctric plug and I added a connectors pair, positioning the male one on the Kinect side and the female one on the electric plug side. Then I prepared another cable with a female connector at one end and two different female blade connectors (faston) on the other end (one for the positive and one for the negative exit). The two female blade connectors are compatible with the two terminals (red/positive and black/negative) of a lead battery (12 V, 7.2 Ah).  In this way it is possible to switch Kinect form the electric net to the battery, simply plugging and unplugging the right cables.

After the hardware modification I was able to test Kinect outdoor. I will write soon a post with the results.