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Post by Ben MnSGC on May 5, 2016 14:14:23 GMT -7
How are the still images saved onto the Pi? I assumed that there would be two copies of each picture, one high quality and one low quality. When we looked at our pictures from the flight we noticed that the picture couples aren't identical. Is this normal? Are they taken a few seconds apart? Another issue that we ran into on both of our flight units was that both of them stopped taking pictures shortly before they landed? Do you know why that might be? Our guess is that they might have stopped when the payloads landed because of the shock. Please let me know if you know why this might be. Thanks.
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Post by Dylan MSGC on May 5, 2016 15:50:03 GMT -7
Hi Ben, The images are saved by taking one high res photo (about 2 seconds) and then changing the resolution and taking a second picture at a lower resolution. This is less than ideal but it is functional for our purposes. We did not find an easy way to take a high resolution, scale it and transmit it. My best guess is the shock for your case. If the camera disconnects on impact while it is trying to take a picture, the system will drop the "camera" module software wise. To be honest, this is not an issue we've had in the past with our payloads. Can you describe your packaging for these systems? Any chance the battery power cycled or something regarding power on impact? David MSGCAny thoughts? |
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Post by David MSGC on May 6, 2016 14:27:48 GMT -7
Just expand on Dylan's reply:
The high and low resolution photos are just under 1 second apart, to make them the "same" image is not worth the overhead required of the pi to post process a high res picture to a lower resolution. It was never meant to be the same picture.
Even if the power cycled when hitting the ground it would still create a new folder with a more recent time stamp for the file name and continue taking pictures once the power was restored. If it where a power cycle you would still have pictures while on the ground. My guess is that the SD card came loose when hitting the ground. Can't say for sure since I have not run into this yet and would be curious to find out what it is if not the SD card coming loose.
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Post by leviw on Sept 8, 2016 10:29:46 GMT -7
It seems like something like the imagemagick library could downscale the high quality image faster than picamera could take a new picture, but I haven't tried it so maybe that's not the case. There's something to be said for "If it's not broke, don't fix it." |
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Post by David MSGC on Sept 8, 2016 14:29:44 GMT -7
I looked at our time stamps of our last flight and there was a 20 - 30 millisecond difference between the two pictures but the imagemagick looks interesting.
In the beginning the goal was to send a picture from the payload to the ground, which is more feasible with a lower resolution picture. The "higher" resolution picture was added with the idea of "we are already up there with a camera that is not very busy, why not take more pictures."
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