Added Ion cross-post and pi pan-tilt article & images

pages/about.md

@@ -34,6 +34,10 @@ continuing there full-time when I graduated in 2010.  I did some
 interesting work there combining software development and research
 around signal processing, image processing, and computer vision.
 
+While at UC, I happened into some [cinci2600](https://cinci2600.org/)
+meetings and eventually became a founding member of [Hive13][].  I'm
+regularly found there, and on occasion give talks.
+
 Around 2014 I moved to a startup, Urbanalta, and here I designed PCBs
 and wrote embedded software.  This is where I started using Haskell
 more intensively on the embedded side, eventually co-creating
@@ -61,3 +65,4 @@ computational photography, machine learning.
 
 [HaskellEmbedded]: https://haskellembedded.github.io/
 [Ion]: https://haskellembedded.github.io/
+[Hive13]: http://hive13.org/

posts/2016-09-23-ion-crosspost.md

@@ -0,0 +1,10 @@
+---
+title: Post at HaskellEmbedded - Introducing Ion
+author: Chris Hodapp
+date: September 23, 2016
+tags: haskell, haskellembedded
+---
+
+Just a quick note: I finally released my Ion library (it was long
+overdue), and wrote a post about it over at
+[HaskellEmbedded](https://haskellembedded.github.io/posts/2016-09-23-introducing-ion.html).

posts/2016-09-25-pi-pan-tilt-1.md

@@ -0,0 +1,101 @@
+---
+title: Raspberry Pi pan-tilt mount for huge images, part 1
+author: Chris Hodapp
+date: September 23, 2016
+tags: photography, electronics, raspberrypi
+---
+
+Earlier this year I was turning around ideas in my head - perhaps
+inspired by Dr. Essa's excellent class,
+[CS6475: Computational Photography][cs6475] - about the possibility of
+making an inexpensive, relatively turn-key rig for creating very
+high-detail photographs, ideally in HDR, and taking advantage of
+algorithms, automation, and redundancy to work with cheap optics and
+cheap sensors.  What I had in mind had a pretty commonly-seen starting
+point for making panoramas - something like a telephoto lens mounted
+on a pan-tilt gimbal, and software behind it responsible for shooting
+the right pattern of photographs, handling correct exposures,
+capturing all the data, and stitching it.
+
+My aim wasn't so much to produce panoramas as it was to produce very
+high-detail images, of which panoramas are one type.  I'd like it to
+be possible for narrow angles of view too.
+
+Most of my thoughts landed at the same inevitable view that this would
+require lots of custom hardware and electronics, and perhaps from
+there still may need a mobile app to handle all of the heavy
+computations.
+
+Interestingly, this whole time I had several Raspberry Pis, an
+[ArduCam][] board, work history that familiarized me with some of the
+cheaper M12 & CS mount lenses of the telephoto variety, and access to
+a [hackerspace][hive13] with laser cutters and CNCs.  Eventually, I
+realized the rather obvious idea that the Pi and ArduCam would
+probably do exactly what I needed.
+
+A few other designs (like [this][makezine] and [this][scraptopower])
+offered some inspiration, and after iterating on a design a few times
+I eventually had something mostly out of laser-cut plywood, hardware
+store parts, and [cheap steppers][steppers]. It looks something like
+this, mounted on a small tripod:
+
+[![](../images/2016-09-25-pi-pan-tilt-1/IMG_20160912_144539.jpg){width=100%}](../images/2016-09-25-pi-pan-tilt-1/IMG_20160912_144539.jpg)
+
+I am able to move the steppers thanks to [Matt's code][raspi-spy] and
+capture images with [raspistill][].  I put together some code to move
+the steppers in a 2D grid pattern of a certain size and number of
+points.  (Side note: raspistill can
+[capture 10-bit raw Bayer data][forum-raw-images] with the `--raw`
+option, which is very nice.  I'm not doing this yet, however.)
+
+It's still rather rough to use, but it worked well enough that I
+picked up a [25mm M12 lens][25mm-lens] - still an angle of view of
+about 10 degrees on this sensor - and set it up in the park for a test
+run:
+
+[![My shot's not slanted, the ground is](../images/2016-09-25-pi-pan-tilt-1/IMG_20160918_160857.jpg){width=100%}](../images/2016-09-25-pi-pan-tilt-1/IMG_20160918_160857.jpg)
+
+The laptop is mainly there so that I can SSH into the Pi to control
+things and to use [RPi-Cam-Web-Interface][] to focus the lens.  The
+red cord is just Cat 6 connecting their NICs together; the Pi is
+running off of battery here.  If I had a wireless adapter on hand (or
+just a Raspberry Pi 3) I could probably have just set up a WiFi
+hotspot from the Pi and done all this from a phone.
+
+I collected 40 or 50 images as the stepper moved through the grid.
+While I fixed the exposure and ISO values with raspistill, I didn't
+attempt any bracketing for HDR, and I left whitebalance at whatever
+the camera module felt like doing, which almost certainly varied from
+picture to picture.  Automatic whitebalance won't matter when I start
+using the raw Bayer data, but for the first attempt at stitching, I
+used only the JPEGs which already had whitebalance applied.
+
+I stitched everything in Hugin on my desktop PC.  I would like to
+eventually make stitching possible just on the Raspberry Pi, which
+isn't *that* farfetched considering that I stitched my first panoramas
+on a box that wasn't much more powerful than a Pi.  I also had to get
+rid of some of the images because for whatever reason Hugin's
+optimization was failing when they were present.  However, being able
+to look at Hugin's computed pitch, yaw, and roll values and see
+everything lining up nicely with the motion of the steppers is a good
+sign.
+
+The first results look decent, but fuzzy, as $10 optics are prone to
+produce:
+
+[![](http://i.imgur.com/zwIJpFn.jpg){width=100%}](http://i.imgur.com/zwIJpFn.jpg)
+
+More posts will follow soon on this!
+
+[cs6475]: https://www.omscs.gatech.edu/cs-6475-computational-photography
+[ArduCam]: http://www.arducam.com/camera-modules/raspberrypi-camera/
+[hive13]: http://hive13.org/
+[makezine]: http://makezine.com/projects/high-resolution-panorama-photography-rig/
+[scraptopower]: http://www.scraptopower.co.uk/Raspberry-Pi/raspberry-pi-diy-pan-tilt-plans
+[steppers]: https://www.amazon.com/Elegoo-28BYJ-48-ULN2003-Stepper-Arduino/dp/B01CP18J4A
+[raspi-spy]: http://www.raspberrypi-spy.co.uk/2012/07/stepper-motor-control-in-python/
+[forum-raw-images]: https://www.raspberrypi.org/forums/viewtopic.php?p=357138
+[raspistill]: https://www.raspberrypi.org/documentation/raspbian/applications/camera.md
+[RPi-Cam-Web-Interface]: http://elinux.org/RPi-Cam-Web-Interface
+[25mm-lens]: https://www.amazon.com/gp/product/B00N3ZPTE6
+[Hugin]: http://wiki.panotools.org/Hugin