Live data from Hacker News

Rudolf Kálmán Has Died

hungarytoday.hu

1–10 of 74 posts

Re: Rudolf Kálmán Has Died

#3
post #2

Kalman filters are really neat. I wrote one when learning C a while ago and it is just cool what some matrix math can do with practical data. https://github.com/lacker/ikalman Although I guess I should have been calling it a "Kálmán filter" this whole time.

Interesting. I don't see generic Kalman filter implementations too often. Thanks for sharing.

I've always found that determining where to put outputs from disparate sensors as opposed to just filtering a single observation like the GPS output in your example is challenging. Have you tried extending this to include input from other sensors (e.g. accelerometer, gyroscope, magnetometer, etc.)?

Re: Rudolf Kálmán Has Died

#4
post #2

Kalman filters are really neat. I wrote one when learning C a while ago and it is just cool what some matrix math can do with practical data. https://github.com/lacker/ikalman Although I guess I should have been calling it a "Kálmán filter" this whole time.

I've been using it lately for my thesis. Good job!

Re: Rudolf Kálmán Has Died

#5
I was waiting for this headline. Someone edited his wikipedia article last week, but provided no source and no articles were published yet.

The Kalman filter is a fantastic tool. I use it and the particle filter regularly. Both are ubiquitous in robotics and cyber-physical systems and incredibly powerful tools.

Interestingly, Kalman wasn't able to publish it in a prestigious journal at the time and had to settle for a lesser known one.

EDIT: Forgot to finish my sentence...

Re: Rudolf Kálmán Has Died

#6
Just last week I needed to smooth out a display reading on an oven controller. The RTD was being read way too fast so I'd get a lot of flicker between values due to ADC resolution.

In the back of my head I remembered one word: Kalman. This line of code fixed it right up:

   static float display_temp = 0;
   display_temp += 0.04 * (adc_temp - display_temp);

Re: Rudolf Kálmán Has Died

#7

Just last week I needed to smooth out a display reading on an oven controller. The RTD was being read way too fast so I'd get a lot of flicker between values due to ADC resolution. In the back of my head I remembered one word: Kalman. This line of code fixed it right up: static float display_temp = 0; display_temp += 0.04 * (adc_temp - display_temp);

Well, I guess, but, I mean, really… that's a first-order low-pass filter.

Re: Rudolf Kálmán Has Died

#8

Just last week I needed to smooth out a display reading on an oven controller. The RTD was being read way too fast so I'd get a lot of flicker between values due to ADC resolution. In the back of my head I remembered one word: Kalman. This line of code fixed it right up: static float display_temp = 0; display_temp += 0.04 * (adc_temp - display_temp);

That's not a kalman filter.

Re: Rudolf Kálmán Has Died

#10

Just last week I needed to smooth out a display reading on an oven controller. The RTD was being read way too fast so I'd get a lot of flicker between values due to ADC resolution. In the back of my head I remembered one word: Kalman. This line of code fixed it right up: static float display_temp = 0; display_temp += 0.04 * (adc_temp - display_temp);

That's just a linear interpolation between two values: take 96% of the current display value plus 4% of the new value from the ADC, which is the same as finding 4% of the way between the two values. It's a simple generalization of the arithmetic mean, which is the special case of 50%.

I'm skeptical that anyone sane would credit this obvious idea should to one particular person, which is why it can't be the Kalman filter.

Post reply on HN