This year was the 40th anniversary of the first man landing on the Moon. I have been very moved by this Apollo anniversary and it got me thinking.
I first took a picture of the Moon with my Ixus during day time actually. It was pretty impressive to start seeing details I had never noticed. Then I tried with my EOS and a 300mm zoom and managed to see actual craters.
Then I realized something pretty obvious when I managed to find the name of some craters online. The features are part of reality. That's pretty obvious I agree. But it's really striking that something so remote and that can be so easily ignored in our daily lives is actually real and that I will observe the same features that other people saw hundreds of years ago.
I have started looking into how to see more detail with some image processing. It's pretty interesting actually. A common practice is to stack pictures to improve signal to noise ratio and even increase resolution.
A rather obvious way to see more detail is to get a telescope. I have found that 25inch is about the maximum that you could buy without remortgaging your home. Obsession Telescopes sells Dobsonian telescopes for 14000$. That's 7 times more than a 16inch telescope apparently, so it's not exactly affordable. That machine resolve at about a millionth of a radian which means that one can see details of about 400 meters.
I was also impressed by how much more volume and relief I saw on areas where the sunlight was almost tangential to the moon surface as it cast long shadows. This made me wonder how much more detail one could extract by combining pictures where the sunlight is coming at different angles.
Currently it's way too cold and I don't really have the time to work on image processing but I looked into using my EOS350D and a 300mm to capture a lot of images. I plan on using gphoto2 to drive the capture.
I would like to stack the pictures geometrically: I plan on tracking the moon in the pictures and assuming the camera is steady enough I would stack the pictures based on when the pictures were taken and the speed of the moon.
The main issue with this plan is to keep the camera steady as both the mirror and the shutter can cause vibrations that can cause shifts of several pixels according to comments I have seen online.
To improve the timestamping of the pictures (1 second in EXIF), I thought of recording ambient sound and detecting the shutter sound. This provides a rather obvious and cheap way of dating the frames down to a couple milliseconds.
I guess this post must be pretty boring but to me every paragraph sums up thoughts that were a lot of fun to entertain.
Tuesday, December 22, 2009
Friday, August 7, 2009
Simple goodies blow my mind
There is nothing really new and that I didn't know already with the tools I am writing about but when I downloaded them I started using them they just blew my mind.
One is SSHFS which is base on FUSE. I can't use NFS from my Virtual box machine but I can SSH into some Unix servers. With SSHFS I can make any of those remote file systems feel local for ANY program (not just KDE tools or Gnome ones etc.). That's not really incredible or new. Actually the only reason I had not done it was that I thought it was no big deal (Konsole and ssh provide most of the convenience already, don't they?).
The other thing I tried was tsearch2 (Postgresql's full text search) in my little Django app. I found a snippet that wraps tsearch2 in a Django very nicely.
I just had to make my model inherit from SearchableModel, add a SearchManager in the definition, alter the table to add a search_index column of type tsvector. Then I simply changed a few lines in my current search view and form to combine the new search with the full text search.
Again, this is nothing incredibly new and actually a feature I had planned on implementing for a while. But now it's here, so easily, it feels like a tremendous change.
Oh well, maybe I am a bit to enthusiastic and I had too much coffee, but color me impressed.
Maybe I am in the mood to be happy
One is SSHFS which is base on FUSE. I can't use NFS from my Virtual box machine but I can SSH into some Unix servers. With SSHFS I can make any of those remote file systems feel local for ANY program (not just KDE tools or Gnome ones etc.). That's not really incredible or new. Actually the only reason I had not done it was that I thought it was no big deal (Konsole and ssh provide most of the convenience already, don't they?).
The other thing I tried was tsearch2 (Postgresql's full text search) in my little Django app. I found a snippet that wraps tsearch2 in a Django very nicely.
I just had to make my model inherit from SearchableModel, add a SearchManager in the definition, alter the table to add a search_index column of type tsvector. Then I simply changed a few lines in my current search view and form to combine the new search with the full text search.
Again, this is nothing incredibly new and actually a feature I had planned on implementing for a while. But now it's here, so easily, it feels like a tremendous change.
Oh well, maybe I am a bit to enthusiastic and I had too much coffee, but color me impressed.
Maybe I am in the mood to be happy
Tuesday, July 7, 2009
KDE 4 on Ubuntu
There has been some controversy in the Gnome world recently and it reminded me of KDE. There had been a similar discussion of Qt's lack of freedom years ago.
This prompted me to think about the runtimes I was using (GTK, Java, Mono, Qt, Python etc.) . I was not really convinced by Mono or Red Hat's stance against Mono. So I thought I could give KDE a try even though Ubuntu has chosen Gnome.
So I did apt-get install kubuntu-desktop on my EEE 701 and in Virtual Box.
The result was very pretty, quite slick. I even noticed an improvement in screen refresh speed when switching desktops in Virtual Box (notably Gnome-terminal always seemed a bit slow to repaint and Konsole feels a bit snappier).
I like the way the settings are handled, there is a search bar to find settings, advanced settings are in a separate tab, the management of keyboard shortcuts is a breeze and accessible from every application. I am not sure if it's better than Gnome, just more obvious to me.
Kmail seems like I could use it for work whereas I felt like Thunderbird had slow repaint issues in Virtual Box too.
The only issue I have is that a few applications seem to crash on exit. It's not a big deal but I find that a bit annoying. I guess I am going to need to follow up on these issues as I like KDE and I want to keep using it.
This prompted me to think about the runtimes I was using (GTK, Java, Mono, Qt, Python etc.) . I was not really convinced by Mono or Red Hat's stance against Mono. So I thought I could give KDE a try even though Ubuntu has chosen Gnome.
So I did apt-get install kubuntu-desktop on my EEE 701 and in Virtual Box.
The result was very pretty, quite slick. I even noticed an improvement in screen refresh speed when switching desktops in Virtual Box (notably Gnome-terminal always seemed a bit slow to repaint and Konsole feels a bit snappier).
I like the way the settings are handled, there is a search bar to find settings, advanced settings are in a separate tab, the management of keyboard shortcuts is a breeze and accessible from every application. I am not sure if it's better than Gnome, just more obvious to me.
Kmail seems like I could use it for work whereas I felt like Thunderbird had slow repaint issues in Virtual Box too.
The only issue I have is that a few applications seem to crash on exit. It's not a big deal but I find that a bit annoying. I guess I am going to need to follow up on these issues as I like KDE and I want to keep using it.
Wednesday, June 24, 2009
Switched to Ubuntu
I have switched my EEE PC 701 to Ubuntu. I had been running Fedora 10 before that but I was disappointed when preupgrade did not seem to work. So as Ubuntu was very nice in my Virtual Box setup at work, I installed that instead of doing a clean Fedora 11 install.
One thing that had impressed me was that Ubuntu had handled the 8.10 to 9.04 upgrade seamlessly in my Virtual Box setup. It even had offered to upgrade while I was updating packages.
This, I think, is representative of the difference between Fedora and Ubuntu. The goals of Ubuntu are clearly defined and it's easy to tell when they fail: if it's not easy and seamless, they failed and they have to fix it.
For Fedora on the other hand, the target audience is less clear (power users, developers, people who want the bleeding edge, users of Red Hat Enterprise at work etc.) and I tend to think that the distinction between Red Hat Enterprise and Fedora adds to the confusion. As a result, it's less clear what a release should look like and what is more important: convenience for existing users or new features and improvements.
In the case of the upgrade to 11, the Fedora site even had a page telling me I should reinstall cleanly instead of upgrading. Quite the contrary of Ubuntu trying to lure me into upgrading and making it much easier and more natural than reinstalling.
This does not seem like much but that's how I ended up abandoning Fedora. That was not easy as I always liked Fedora and I prefer rpm over dpkg any day.
I wonder if and when I'll go back to Fedora. Any way, I thought it was good to write all this down, so that I can look at it again when I switch distros. I guess I am in for a good laugh when I read this post again ;-)
One thing that had impressed me was that Ubuntu had handled the 8.10 to 9.04 upgrade seamlessly in my Virtual Box setup. It even had offered to upgrade while I was updating packages.
This, I think, is representative of the difference between Fedora and Ubuntu. The goals of Ubuntu are clearly defined and it's easy to tell when they fail: if it's not easy and seamless, they failed and they have to fix it.
For Fedora on the other hand, the target audience is less clear (power users, developers, people who want the bleeding edge, users of Red Hat Enterprise at work etc.) and I tend to think that the distinction between Red Hat Enterprise and Fedora adds to the confusion. As a result, it's less clear what a release should look like and what is more important: convenience for existing users or new features and improvements.
In the case of the upgrade to 11, the Fedora site even had a page telling me I should reinstall cleanly instead of upgrading. Quite the contrary of Ubuntu trying to lure me into upgrading and making it much easier and more natural than reinstalling.
This does not seem like much but that's how I ended up abandoning Fedora. That was not easy as I always liked Fedora and I prefer rpm over dpkg any day.
I wonder if and when I'll go back to Fedora. Any way, I thought it was good to write all this down, so that I can look at it again when I switch distros. I guess I am in for a good laugh when I read this post again ;-)
Friday, June 19, 2009
Notes
I have been looking at tools for taking notes and using quite a few for different purposes.
Archiving emails, bookmarks are pretty basic and common but they were lacking for many reasons.
Since a lot of the interesting stuff I come across is on the web, Scrapbook and Zotero were to pretty natural extensions of bookmarks. I tend to prefer Zotero and my only gripe is that it parses the html of the pages I load which is slowing me down when accessing big source files through opengrok .
For more local notes I have used:
Now, this description might seem a bit vague but I feel that it corresponds to a purpose that is not well served by my other note taking tools. This blog being public, it's clear it only contains stuff that can be shared freely, which means I can copy anything from it, access it anywhere without concern of security etc.
The relative privacy of my other note taking tools means that I don't have to sort between public stuff and more private one. As a result they contain a mix of information with different publication/security constraints. This makes it difficult to decide where I can keep copies, where I can access the copies etc. In that respect the added value of the blog is quite clear, so let's see if it works...
Archiving emails, bookmarks are pretty basic and common but they were lacking for many reasons.
Since a lot of the interesting stuff I come across is on the web, Scrapbook and Zotero were to pretty natural extensions of bookmarks. I tend to prefer Zotero and my only gripe is that it parses the html of the pages I load which is slowing me down when accessing big source files through opengrok .
For more local notes I have used:
- a local wiki with a server (notably MoinMoin which is pretty nice and in Python so it's easy to fix the rare problems)
- Tiddlywiki which is a self contained HTML/Javascript page and can show several little pages simultaneously (tiddlers)
- Freemind which is a Java mindmapping tool that shows pretty trees, can fold them easily and allows for quick keyboard only edition
Now, this description might seem a bit vague but I feel that it corresponds to a purpose that is not well served by my other note taking tools. This blog being public, it's clear it only contains stuff that can be shared freely, which means I can copy anything from it, access it anywhere without concern of security etc.
The relative privacy of my other note taking tools means that I don't have to sort between public stuff and more private one. As a result they contain a mix of information with different publication/security constraints. This makes it difficult to decide where I can keep copies, where I can access the copies etc. In that respect the added value of the blog is quite clear, so let's see if it works...
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