Science and engineering of photography

Today I spent most of the afternoon working on a presentation for the university Image Processing course, to be delivered to the students on 10 October, during the first of their project work face-to-face sessions. The lecturer asked me if I wanted to give a guest lecture as part of the session, and I agreed, thinking I could do one on the Science and Engineering of Photography.

I did an outline of the presentation, then started working on slides. This is the part that takes time, as I have to source images that can be used without violating copyright, or make my own. I got through the camera obscura, pinhole camera, what a lens does, how a camera focuses, circle of confusion, and point spread function. I still need to do slides on convolution, the Fourier convolution theorem, pupil function, optical transfer function, depth-dependent blur, aberrations, camera sensor construction, imaging noise, colour filter arrays, image demosaicing, and other post-capture image processing operations. There’s heaps more that I could go into, but I need to keep it down to about 45 minutes.

The slightly annoying thing is that I had a good presentation on exactly this stuff at work, when I used to work for Canon, which I presented a few times to other staff and to visiting interns and students. But since I made that presentation at work, it was on work machines, and I couldn’t bring it home with me. But at least after I do this, I’ll have one handy for future use. I could even adapt it for use to teach kids about how cameras work on Outschool.

This evening I made a special dinner. I’ve always liked fried cauliflower, but it’s a bit of a mess to make. But today we had most of a cauliflower left over as the remaining vegetable before grocery shopping tomorrow, so I decided to go for it. I cut it into florets, coated them in flour, egg wash, and breadcrumbs, and shallow fried them in a pan until golden brown. I served them with a mix-it-yourself set of sauce ingredients: yoghurt, tahini, sriracha, chutney, and mayonnaise. It turned out great! (Except I left a couple of pieces a bit too long before turning them and produced a bit of smoke, but fortunately it dissipated without setting the alarm off.)

New content today:

Trekking north for a day

Today my wife had a day off work, and my only ethics class was from 9am, so I was done by 10 o’clock. We decided to take advantage by going out for the day. We took Scully and we drove up to the northern beaches suburbs, as far as Avalon Beach, almost an hour’s drive.

There we stopped at Oliver’s Pies to get some lunch. We took them across the road to the large park there to let Scully run around while we ate, and after finishing I tossed a ball for her to chase for a while. Then we went for a walk. I wanted to do a path through Bangalley Headland Reserve, and we walked a few blocks to where the track started, but we discovered that dogs were prohibited on the track. So unfortunately we had to return to the car.

Instead, we decided to go to the shopping centre at Avalon and sit at a cafe for a bit so my wife could get some coffee. I got a nutty chocolate treat as well while there, and we discussed what else to do. We decided to stop off at Warriewood Wetlands on the way home, which is a great spot to walk around and spot birds. I had my camera with me, and managed to get a few shots, although we were walking rather than waiting patiently for opportunities.

Willie wagtail:

Willie wagtail

Australasian grebe:

Australasian grebe

Dusky moorhen:

Dusky moorhen

We also saw Eurasian coots, superb fairywrens, silvereyes, Pacific black ducks, and we heard plenty of bell miners, but those guys are almost impossible to spot.

In other news, I got a minor scrape on my left hand while cooking dinner and put a band-aid on it. Then later while washing up, I didn’t want to get my left hand wet, so I swapped hands and held the pots in my left hand while scrubbing them with the dishcloth in my right hand. This felt so weird and uncoordinated! I was curious and asked my friends on our group chat what hands they use to wash dishes, and they all said that they normally hold the item in their left hand and scrub it with the right. My wife said the same thing.

This isn’t the first time that I’ve discovered that I do something the opposite way to other right-handed people. I use my left hand to eat finger food (I just confirmed my friends use their right hands). I know I ride push scooters and skateboards the same way as left-handed people. I tie my shoelaces using a mirror image sequence of moves to right-handed people I’ve watched. But I consider myself right-handed. I write with my right hand, I throw right-handed, I play sports like tennis, cricket, golf right handed.

I was just now searching casually on Google for if this is a known thing – right-handed people doing a whole bunch of things in a left-handed way. And it turns out there’s a term for it! Cross-dominance! I’d never heard of this before, but yes, that’s me. Huh. So I just learnt a thing about myself.

New content today:

Evolutionary Sunday

Today I had another science lesson online with the girl who has been taking those intermittently. Last time we began talking about evolution, and today was the second half of that topic. I prepared some slides showing the Galapagos Islands, Charles Darwin, finch beaks, hybridisation (lions and tigers crossbreeding to produce ligers), induced speciation in fruit flies, evolution of apes, and whales, and horses, and something about the evolution of antibiotic resistance in bacteria. It was a fun class and the student seemed to really enjoy it.

The weather here has turned slightly chilly as we get deep into autumn and start thinking about winter. We’ve had nice sunny days, although with some overnight rain just to keep things damp, but the maximum temperatures have been in the low 20s Celsius, which is noticeably cooler than the past months. And the nights have been getting quite chilly, down around 14°C, which feels like a big change from the overnight lows of 18°C we were getting a few weeks ago. 18°C is comfortable – I was taking Scully out around 10pm for her final toilet in just shorts and a T-shirt, but now I’m having to wear long pants and a jacket to do it.

We took Scully for another walk and ball chasing episode just after lunch, this time down to the nearest ferry wharf and the secluded adjacent park. The park is in a bowl-shaped hollow leading down to the water, so it took some care throwing the tennis ball so that it wouldn’t roll down into the harbour.

Um. I guess it wasn’t an especially interesting day, apart from thinking about evolution a bit.

New content today:

Comic making blur

Today was very busy. I had ethics classes at 9 and 10am, followed by going for my daily run, lunch, and then getting stuck into making another week’s worth of Irregular Webcomic! strips. I wrote 5 strips, photographed them, assembled them, and wrote annotations for them all in just a few hours. By the time I was done I needed a break, because I’d been working solidly the whole time.

This evening I had an ethics extension class, followed by a class of my human vision science lesson. One of the new kids who joined ethics last week found this class and enrolled in it, and he was really keen and enjoyed it a lot. At the end he said he learnt a lot and it was really interesting, so that’s good! And the parent gave me a 5 star review. I should schedule this class more often – it was a lot easier to teach it this time than the previous times, I think because I now have a lot more experience doing this, and felt a lot more relaxed with the material and using Zoom. (I hadn’t taught this class for almost a year, and was only prompted to schedule more classes because Outschool threatened to delist it.)

I cut a pineapple for dessert tonight. We haven’t had a pineapple for some time, and I saw them in the supermarket and just felt like one last time i went shopping. I like to have pieces sprinkled with cinnamon – it really adds something.

Oh, and I updated my desktop machine to MacOS Monterey tonight too. I’ve bene putting this off because previous updates have taken hours to install and I’m never really confident that it’ll work, but this one was relatively painless, and took barely an hour.

New content today:

Ethics of data; and body systems

Today I got in a good chunk of work on the university data engineering course, writing an outline of a presentation on the ethics of data science. I also went over the lecturer’s notes for the lecture on data types and some exercises he’d prepared. We’re having a Zoom meeting tomorrow to discuss progress and plan out the rest of the time between now and the beginning of the course in late February.

The rest of the afternoon I spent assembling slides for tonight’s private Outschool science lesson. Today we’re covering body systems – or at least getting started on it. I suspect I have enough material to last for two weeks.

For dinner tonight I made calzones – spinach and ricotta, with a tomato/onion/garlic sauce to spoon over the top.

New content today:

Starting biology

The Christmas break is over. My wife got up early this morning, and so did I. She’s working from home again, due to COVID, so we’re back into that routine again.

I spent much of the day making slides for tonight’s resumption of online science classes with my one-on-one student. Last year we started with physics, going through atomic theory, electromagnetism, and light. I thought we could start off the new year by changing fields into biology. So today I made a presentation on cells. I found a fantastic collection of public domain microscope images and videos of cells on Flickr, by the Berkshire Community College Bioscience Image Library. And an incredible collection of public domain biology diagrams by one very generous Wikimedia Commons contributor. Together they made a great presentation.

New content today:

Clearing a memory backlog

Two things that happened in the past few days, but which I forgot about when writing here:

1. Yesterday when I was out with my wife walking Scully in the early evening, we were enjoying the quite strong breeze that was cooling down the heat of the day. I didn’t realise quite how strong the wind had become until we happened across a scene on the street: Two young men were examining where a large tree branch had fallen onto the street, blocking it. It was a eucalyptus branch, and pretty substantial – maybe 4 metres long and the diameter of a dinner plate at the base end where it had splintered off the tree above. It was fortunate that nobody had been under it when it fell, as it could have been very dangerous.

But unfortunately the car belonging to one of the men was under it at the time. The branch had caught it at a glancing angle on the side, smashing the tail light and causing some significant dents and scrapes in the bodywork. The guys were maybe teenagers, and one of them looked at us as we approached. They didn’t seem to know what to do, and one asked me who would be liable for the damage to his car – would it be the local council? I answered that I didn’t think anyone would be liable, and the damage would need to be covered by his insurance.

We left then trying to pull the branch away from the car, but they weren’t having much luck as it was pretty heavy. This morning when I walked past the same spot, I saw that the State Emergency Service had come to chop the branch into firewood sized chunks and has piled it up by the side of the street, with emergency tape around it.

2. A few nights ago, I think it was the night of 30 December, I took Scully out for her pre-bedtime toilet. As I always do, I gaze up at the stars (assuming a cloud-free night). Orion is prominent in the northern sky at the moment, with red Betelgeuse at the bottom, and the bright blue of Sirius in Canis Major trailing it to the right. (This is upside down compared to what people in the northern hemisphere see, of course.)

Anyway, I was looking up at Orion, when I saw a very bright streak of light flash rapidly from east to west, just below the constellation. It was a meteor. I see them occasionally when taking Scully out, but this was one of the brightest I’ve seen. So that was pretty cool.

Today, I spent time assembling and writing annotations for Irregular Webcomic! strips for the coming week. I got stuck into some mathematics for one of them, so it took some time. I even had to break out Matlab to do some calculations.

For dinner I made quiche, with home made shortcrust pastry. Previously I’d been rolling the pastry cold from the fridge, and wondering why it always cracked around the edges. Searching the net turned up some advice to let it warm up a bit before rolling, and that seemed to help a fair bit, so I’ll do that from now on.

New content today:

Trigonometric survey

In my friends’ Discord chat today one of them posed this:

Survey question. You’re doing a trigonometry question. It says you’re standing on a cliff 250m high looking at a rock that’s 450m away. Is 450m the hypotenuse or the base of the resulting triangle?

Just to be silly, I quickly drew this:

Trig drawing 1

But then another friend one-upped me with this:

Trig drawing 2

Incidentally, the original friend asked “Survey question” because he was surveying us to find out what we thought of this poorly framed high school maths question. A coworker had asked him for advice on what to advise his child while doing homework, and my friend decided to canvas for opinions. But at least two of us thought he’d said “Survey question” as a prelude to a question about surveying. English is funny sometimes.

This evening I had a Zoom meeting for ISO photography standards. This is an ad-hoc group meeting for one particular standard: ISO 15739 Visual Noise, held between the regular week-long digital photography meetings. The group of experts working on this particular standard have ongoing experimental work to discuss, so the project leaders organised this interim meeting to go through some technical details. We met for 90 minutes, and there was a lot of very interesting discussion. We agreed on the plan for further experimentation, which will be done hopefully it time for the next meeting in October.

For dinner tonight I varied my pizza making by trying out some calzones.

Calzones for dinner

I filled one with spinach and ricotta, and the other with mushrooms and ricotta. I didn’t know how much the insides would cook in the oven, so I pre-cooked the spinach and the mushrooms, and that seemed to work well. I also made a tomato sauce with garlic, onions, and herbs for spooning on top.

Calzones for dinner

They turned out really well! I was a little worried about the insides leaking in the oven, but they were fine, and delicious. My wife told me I can definitely make these again.

New content today:

Lunar eclipse night!

This morning was my weekly Ethics class at school. The kids were a bit boisterous last week, so at the start of today’s lesson I laid down the law a bit for them, and their behaviour today was a lot better. We finished off the topic on vanity, with the final question for discussion being (paraphrased): Should people think about how vain they are, and what the consequences of that might be? There were some good answers to this, so that was good!

Today… let’s see. I made sourdough bread, and finished off making that latest batch of Irregular Webcomic! strips. And looked after Scully for a bit.

Tonight is the total lunar eclipse, which is visible in prime time here in Sydney. I’m about to head outside in a few minutes to take some photos…

… And the weather was perfect.

Lunar eclipse 2021-05-26

Lunar eclipse 2021-05-26

Lunar eclipse 2021-05-26

New content today:

Big Lunch

My wife has taken this week off from work to use up some of her annual leave, and today we planned to go out for a nice lunch somewhere. We’d discussed a few options earlier in the week, but this morning she found a place that looked good and called up to book us a table for lunch, making sure we could bring Scully along.

We ended up at The Butcher’s Block in Wahroonga, a suburb about half an hour’s drive north of us. We got there a bit early so we took Scully for a walk around Wahroonga Park, which is a lovely bit of parkland with small rolling hills dotted with large trees, some of which were dropping autumn leaves, as well as gazebos, benches, statues, and plenty of birds. It felt a bit like a quintessentially English park.

At the restaurant we sat out the front on a padded bench facing the street, where we could see all the people walk by. Next door was a sushi place doing really good business with people popping in to grab a bento box or whatever to take away. But the place we’d chosen was excellent, with a fancy menu and attentive waiters. Although the pasta dishes looked amazing, I opted for something a bit more lunchy and chose the barbecue beef burger, with sweet potato chips.

Angus & Brisket burger

The burger had an Angus beef patty and pulled brisket, and it was very good. I also had a chocolate thick shake, and I’m happy to say it was a serious thick shake. I’ve had some disappointing ones elsewhere, where they really should have just been called milkshakes. But this one was a huge tall traditional steel milkshake cup, filled to the brim with what was basically ice cream barely on the verge of melting. And it was richly chocolatey. It was really really good.

It was so filling that it’s now after 8pm, and I haven’t eaten anything since lunch… and I really don’t feel like having dinner.

With the rest of the day I worked on a couple of things. I had to deal with insurance stuff for my market stall. Up to now I’ve been buying public liability insurance on an ad-hoc basis from the market operator each time I had a stall. But I’m planning to do another different market next month and they don’t offer this service, so I needed to get my own liability insurance if I wanted to do the market. I did some research and found a policy that will cover me for a year, meaning I can stop buying insurance individually for each market. It’s actually a bit more expensive overall, but, well, it’s a cost of doing business – so at least it’s tax deductible.

And in between I worked on more outlines for my Big Science course. Today I completed ones for quantum mechanics and plate tectonics. I also went back over the ones I did yesterday to add linkages to the other topics – there are surprisingly many. I should draw a mind map of the whole thing when I’m done with the outlines. It will be a good graphic to show during the course.

New content today: