coordinate transformation

I got confused over time of coordinate transformation for a point in space v.s. transformation of a point location with fixed coordinates. It turns out that the former is the exact reverse of the latter. I don’t include a proof here, but it should be self-evident. Also it is much easier to understand coordinate transformation…

YOLOV5 with Realsense on Jetson

As titled. Tried to follow the guide from here. Have some problems running realsense camera. The guide from jetsonhack is okay. But cannot find pyrealsense2 in python. Adding pythonpath solved the import problem but the imported package contained no method. Copying all so files (pybackend2.cpyton-*) to the working folder seems to resolve the problem. The…

jetson agx xavier hack

Some of my experiences I got playing with Jetson Xavier. I got lots of trouble to start with trying to flash Jetson. It ended up that I simply needed to remove the tlp package at the host. The log from sdkmanager is simply not very helpful. Otherwise, it should have saved me lots of time…

Jetson AGX Xavier experience

Just played with it a bit. So far my experience is horrible. Nvidia is notorious for poor support in software. I think this one is especially unacceptable. First, I really don’t understand why the installation can be so complicated. I need a host computer connected to the device with a USB cable emulating a network…

War on Ukraine

A talk by Professor Mearsheimer 6 years ago explained very well the motive of Putin. https://youtu.be/JrMiSQAGOS4A First, the point usually missed by everyone is that NATO is a nuclear power and it is hard for Russia to swallow a nuclear power adjacent to it. So Russia reacted so violently as Ukraine tried to join the…

Touchscreen not working after power outage

My X1 Yoga gen 3rd died after I used in outside freezing. The battery died completely and it crashed the hard disk as well. After I replaced both, touch screen does not work but stylus is half functioning. It doesn’t work near the bottom edge. I originally suspect the battery. But I used the UEFI…

dropbox is not syncing anymore

I use dropbox to manage my website. It is not really very secure. But it is at least very convenient. I use one dummy dropbox account contain just my website folder shared from my main dropbox account. Then I just login dropbox with my dummy account for my web server.   It has been working…

Natural scrolling for 18.04

Unity doesn’t have an natural scrolling option on 18.04. One can enable that with libinput   To enable Natural Scrolling in libinput add Option “NaturalScrolling” “true” to /usr/share/X11/xorg.conf.d/40-libinput.conf. It should be added before EndSection to the touchpad section. Unity desktop GUI app can’t use libinput options. You can switch to synaptics by sudo apt remove xserver-xorg-input-libinput sudo apt install xserver-xorg-input-all  …