03-29-2016, 08:03 PM
(03-29-2016, 04:11 PM)RodgerRoentgen Wrote: For the other side of the equation, we'll need to firm up the numbers you observe with the recordings you have made. 10 FPS is reasonable for your recordings. Also consider if you are compressing time when you record, we need to factor that in. For example, if playback is at 2x speed (1 min play = 2 min record), we need to account for that in the FPS value.
Glad you're up for number juggling. Not compressing time when recording. Only use 1.5x and 2x for playback to save time.
Quote:ok, we'll also want to consider the recorded vs. streamed FPS. While you may record @ 10, the stream could be less (or more). One way to check is to step through all 10 frames in 1 second. If there are any frames that are identical, you'll need to subtract the number of duplicates from the total FPS. For example, if in 10 frames, 2 frames are duplicated (4 frames total, 2 individual pairs), then a realized frame rate is 8 FPS.
The new tepco stream comes with duplicate frames. In 10 frames half are duplicates. That changed with the flowplayer. In the old streams a spark was one frame; with the flowplayer, sparks are two frames, the extra frame a duplicate. That’s why I guessed they were adjusting the frame rate on the new flowplayer. In 10 frames, 5 frames are duplicated so the realized frame rate is 5 fps.
Quote:The calculation of 1 dot per frame = .1mSv was not based on any hard numbers. To come up with that number I guessed many things. I guessed the following:I poorly assumed 30 thinking back to NTSC, but clearly the live stream is more like 10
- Frame rate FPS
The video just had 'over 20mSv/hr' in the description, so I guessed higher @ 25mSv/hr, but again we don't have any idea how accurate that number is.
- Dose/Rate
even this I really cheated on, I roughly counted the dots in one quarter of one frame. This is a very unreliable number considering we can sample more data to get better averages.
- Dots per frame
The video of the interior of the reactor was probably taken with a better camera than the tepco feeds, so I’d stick with the 30fps. The dose/rate guess @25mSv/hr is good enough for starters, considering that could still be a low-ball number. The dots per frame count; that was smart counting a quarter and extrapolating. The dots per frame would vary considerable, but a snapshot count is good enough for starters.
Agree we should try to get a reliable count for the reference part of the ratio; I’ll look for more tepco video showing dots with a Geiger count, maybe Chas or Cali have links handy. The ISS recordings are no help because they don’t include a radiation reading.
I hope differing frame rates don’t affect the ratio we’re trying to build.
Reference count at 30 fps :: tepco count at a realized 5 fps
I picked a tepco count of 20 dots per hour because that’s when the emissions get thick and I use it as an indicator that something is steaming up. Once we get a realistic reference for the ratio, plugging in tepco counts should be easy.
I know you’re worried about the accuracy of the numbers and that’s good. Would like to plug in some numbers and see if we’re getting realistic results.
"The map is not the territory that it is a map of ... the word is not the thing being referred to."