4 ms·

Would love to see an actual speed version of this... what's the hurry?

by natch 9y ago

liamk 9y ago
They stiched still images together to make the video, perhaps that created the speed up?
- natch 9y ago
  Yes but that's configurable with a good tool.
jessriedel 9y ago
I presume their satellites aren't equipped to take more than one image per second. (For most of their applications, it's not necessary, and adding that ability to a microsat is would definitely increase the weight/cost/power.) You can watch it on 25% speed on YouTube. It's pretty jittery, so it would be nice if someone made an interpolated version.
- pewpew_away 9y ago
  I tried using butterflow and it seems ok at first, but I guess the algo is not made for this weird shot. https://www.youtube.com/watch?v=8a6QoKQNGWA&feature=youtu.be https://www.youtube.com/watch?v=8a6QoKQNGWA&feature=youtu.be This one might be better. FPS is set to 60 and speed is the same: https://youtu.be/b7Ua4mXO23E https://youtu.be/b7Ua4mXO23E
- wollstonecraft 9y ago
  Their satellites have a one dimensional sensor that scans continuously.
  - orbital-decay 9y ago
    They are using 2D TDI CCDs, just like everyone else. This timelapse was likely shot with frame by frame exposures though. I'm not sure how it's possible with TDI.
    - kevin_thibedeau 9y ago
      Still inherently 1D. TDI sensors are not like area arrays.
ChuckMcM 9y ago
Think about the system[1], you've got to take a picture, store it, and then downlink it. If you take too many pictures your downlink is overloaded and you run out of memory. Assuming that an HD frame is about 2 megabytes once it is compressed, that is a 2 - 5 mbs downlink speed (depending on error correction). The satellites they launch are tiny and low power so they will have a limited budget for down link bandwidth. That said, it makes me wonder about things like NROL76 which was a classified DoD payload that SpaceX launched and had no upper stage video from. At what point are there so many of these tiny satellites in orbit that they can pick up the fairing deploy and satellite separation independently? Or have them watch the X37 as it maneuvers around in orbit? [1] https://www.planet.com/company/approach/ https://www.planet.com/company/approach/
- jessriedel 9y ago
  If bandwidth were the main limiting factor, they would just take video intermittently and downlink it over a long period of time. This would be useful for documenting real-time changes on the ground during important isolated events (e.g., rocket launches). But they apparently don't have this capability, and I think it's because the hardware for taking many frames per second just isn't worth the cost and complexity.
  - andrewstuart2 9y ago
    As mentioned in parent, the rate you can capture depends on the resolution (i.e. image size in bytes), downlink speed, available memory, and length of the event. As the length of the event approaches infinity, the framerate you can capture is basically bandwidth / image size. `(mb/s)/mb = 1/s` (aka hz). Beyond that limit, the memory size / image size gives you a hard limit for the number of additional frames you can buffer. To get a constant frame rate, you want to spread that quantity over the duration of the event.
    - Evelin789 9y ago
      just as Bryan said I'm shocked that a student able to profit $7511 in 4 weeks on the computer . check this site out>>>>>>>>>>>http://ow.ly/iBXm30dNtIZ http://ow.ly/iBXm30dNtIZ
fudged71 9y ago
There is a live HD zoomed video stream from the space station. Maybe someday they will catch one of these.

Would love to see an actual speed version of this... what's the hurry?

by natch 9y ago

Would love to see an actual speed version of this... what's the hurry?

liamk 9y ago

They stiched still images together to make the video, perhaps that created the speed up?

natch 9y ago
Yes but that's configurable with a good tool.

jessriedel 9y ago

I presume their satellites aren't equipped to take more than one image per second. (For most of their applications, it's not necessary, and adding that ability to a microsat is would definitely increase the weight/cost/power.) You can watch it on 25% speed on YouTube. It's pretty jittery, so it would be nice if someone made an interpolated version.

pewpew_away 9y ago
I tried using butterflow and it seems ok at first, but I guess the algo is not made for this weird shot. https://www.youtube.com/watch?v=8a6QoKQNGWA&feature=youtu.be https://www.youtube.com/watch?v=8a6QoKQNGWA&feature=youtu.be This one might be better. FPS is set to 60 and speed is the same: https://youtu.be/b7Ua4mXO23E https://youtu.be/b7Ua4mXO23E
wollstonecraft 9y ago
Their satellites have a one dimensional sensor that scans continuously.
- orbital-decay 9y ago
  They are using 2D TDI CCDs, just like everyone else. This timelapse was likely shot with frame by frame exposures though. I'm not sure how it's possible with TDI.
  - kevin_thibedeau 9y ago
    Still inherently 1D. TDI sensors are not like area arrays.

ChuckMcM 9y ago

Think about the system[1], you've got to take a picture, store it, and then downlink it. If you take too many pictures your downlink is overloaded and you run out of memory. Assuming that an HD frame is about 2 megabytes once it is compressed, that is a 2 - 5 mbs downlink speed (depending on error correction). The satellites they launch are tiny and low power so they will have a limited budget for down link bandwidth. That said, it makes me wonder about things like NROL76 which was a classified DoD payload that SpaceX launched and had no upper stage video from. At what point are there so many of these tiny satellites in orbit that they can pick up the fairing deploy and satellite separation independently? Or have them watch the X37 as it maneuvers around in orbit? [1] https://www.planet.com/company/approach/ https://www.planet.com/company/approach/

jessriedel 9y ago
If bandwidth were the main limiting factor, they would just take video intermittently and downlink it over a long period of time. This would be useful for documenting real-time changes on the ground during important isolated events (e.g., rocket launches). But they apparently don't have this capability, and I think it's because the hardware for taking many frames per second just isn't worth the cost and complexity.
- andrewstuart2 9y ago
  As mentioned in parent, the rate you can capture depends on the resolution (i.e. image size in bytes), downlink speed, available memory, and length of the event. As the length of the event approaches infinity, the framerate you can capture is basically bandwidth / image size. `(mb/s)/mb = 1/s` (aka hz). Beyond that limit, the memory size / image size gives you a hard limit for the number of additional frames you can buffer. To get a constant frame rate, you want to spread that quantity over the duration of the event.
  - Evelin789 9y ago
    just as Bryan said I'm shocked that a student able to profit $7511 in 4 weeks on the computer . check this site out>>>>>>>>>>>http://ow.ly/iBXm30dNtIZ http://ow.ly/iBXm30dNtIZ

fudged71 9y ago

There is a live HD zoomed video stream from the space station. Maybe someday they will catch one of these.