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by HermannSW
Tue Jun 25, 2019 12:35 am
Forum: Camera board
Topic: Pi cameras as [soldering] maginifying glass
Replies: 0
Views: 48

Pi cameras as [soldering] maginifying glass

I used v1 and v2 cameras in this thread extensively: https://www.esp32.com/viewtopic.php?f=19&t=11126 Either with self added M12 mount and lens, or v1 cameras bought with that, the lens allows adjustment to different height above scene sharp images, and therefore different resolutions. First I did u...
by HermannSW
Sun Jun 23, 2019 12:35 am
Forum: HATs and other add-ons
Topic: Qs on official Raspberry Pi [3]A+ Case
Replies: 2
Views: 532

Re: Qs on official Raspberry Pi [3]A+ Case

Got so used to using these headless or via a web page I must try it as a desktop one day... Most of the time I use the Pi3A+ headless via ssh as well (like my other PIs). You may ask why to connect HDMI monitor in that case ‒ for me the reason is raspi(vid|still) camera preview. I need to install o...
by HermannSW
Sat Jun 22, 2019 5:37 pm
Forum: Camera board
Topic: Raspberry no IR-filter camera see-through images
Replies: 0
Views: 444

Raspberry no IR-filter camera see-through images

I have used Raspberry v[12] NoIR cameras only for capturing in the dark sofar, if not capturing at normal daylight. In thread "ESP32-CAM ov2640 exposure control/FREX mode" https://www.esp32.com/viewtopic.php?f=19&t=11126 I try to bring ov2640 sensor into FREX mode as I did with Raspberry v1 camera (...
by HermannSW
Sat Jun 22, 2019 2:46 pm
Forum: HATs and other add-ons
Topic: Qs on official Raspberry Pi [3]A+ Case
Replies: 2
Views: 532

Qs on official Raspberry Pi [3]A+ Case

Today I received my first Pi 3A+ (have Pi0, Pi0W, 2B+, 3B and 3B+ models sofar). Because buying Pi 3A+ plus official Raspberry Pi [3]A+ case allowed for free shipping, with cost less than the cost of Pi 3A+ alone plus shipping, I ordered both. After installing Raspberry Pi Stretch and configuring ca...
by HermannSW
Sat Jun 22, 2019 12:04 am
Forum: Camera board
Topic: Pi zero w camera
Replies: 1
Views: 137

Re: Pi zero w camera

You can use Raspberry v1 as well as v2 camera with Pi0[W], only a different flat ribbon cable is needed: https://www.raspberrypi.org/app/uploads/2016/05/2016-05-15-16.32.19-500x375.jpg https://www.raspberrypi.org/homepage-9df4b/static/1253242e1a7766dbc0af51edcf1a43a1/c6096/ccfc5f9d175e980d1ec193d737...
by HermannSW
Thu Jun 20, 2019 11:24 pm
Forum: Camera board
Topic: RPi can't sent video (and audio) when joining a Jitsi meeting room
Replies: 10
Views: 1737

Re: RPi can't sent video (and audio) when joining a Jitsi meeting room

Somebody should report the issues on u4vl project contacts page:
http://www.linux-projects.org/contact/
by HermannSW
Thu Jun 20, 2019 7:13 pm
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 24
Views: 2309

Re: Raspberry v1 camera global (external) shutter videos

I used OpenCV calibrate.py script: https://github.com/opencv/opencv/blob/master/samples/python/calibrate.py After fixing some problems with splitfn and getting pellet image in addition to training chessboards undistorted, this is the undistorted second to last frame -- all pellets on a straight line...
by HermannSW
Thu Jun 20, 2019 5:13 pm
Forum: Camera board
Topic: best compromise quality/size for time-lapse camera
Replies: 9
Views: 451

Re: best compromise quality/size for time-lapse camera

If you need more than 200fps, the solution has to be based on raspiraw because GPU limits to 200fps. In this posting you can see how to intercept raspiraw's frame capturing and control servo for robot camera tilt calibration: https://www.raspberrypi.org/forums/viewtopic.php?t=189661#p1231151 I conve...
by HermannSW
Thu Jun 20, 2019 12:51 am
Forum: General discussion
Topic: Using RasPi for multiple display outputs
Replies: 13
Views: 459

Re: Using RasPi for multiple display outputs

What I can't seem to figure out is how to use a remote command to make the monitor connected to the RPI to display an image file. Besides what others said, I like to use omxiv to view images. One reason is that its hardware accelerated and much quicker than eg. "eog" X11 image viewer. The other is,...
by HermannSW
Thu Jun 20, 2019 12:34 am
Forum: Camera board
Topic: best compromise quality/size for time-lapse camera
Replies: 9
Views: 451

Re: best compromise quality/size for time-lapse camera

and how can I detect darkness using picamera to trigger a shutdown? how do I read the image and see if most of pixels are beyond a threshold close to black? I don't use picamera, but you can use picamera Array API. For black detection you may use PiYUVArray and only look at the Y component: https:/...
by HermannSW
Wed Jun 19, 2019 9:12 am
Forum: Camera board
Topic: Review: Graspinghand gooseneck camera mount
Replies: 8
Views: 415

Re: Review: Graspinghand gooseneck camera mount

ghawkins wrote:
Wed Jun 19, 2019 7:54 am
I just ordered it direct from the GraspingHand website.
Thanks, just bought one (9.95€ plus €3.60 shipping).
by HermannSW
Tue Jun 18, 2019 9:33 pm
Forum: Camera board
Topic: Review: Graspinghand gooseneck camera mount
Replies: 8
Views: 415

Re: Review: Graspinghand gooseneck camera mount

And yes - it seems to work out well enough, I thought the "arm" might bounce about too much when the thing is in motion but it seems to be OK. Nice, but usability depends of speed of robot (and whether running on flat surface, or off road outside). For my first caterpillar robot platform I fixated ...
by HermannSW
Tue Jun 18, 2019 8:42 pm
Forum: Camera board
Topic: open discussion on the camera latency
Replies: 7
Views: 1969

Re: open discussion on the camera latency

If you have LOTS of light, then exposure time can be down at a few milliseconds. Off topic, but if you really have lots of light , then exposure time can be down to a few micro seconds. Below frame is lighted with 2×5000lm leds , and multiple exposures of 8.33µs strobe pulse length at 9kHz PWM freq...
by HermannSW
Tue Jun 18, 2019 4:14 pm
Forum: Camera board
Topic: open discussion on the camera latency
Replies: 7
Views: 1969

Re: open discussion on the camera latency

If you try to do a gstreamer streaming solution, take jitterbuffer into account: https://www.raspberrypi.org/forums/viewtopic.php?f=43&t=204921&p=1273950#p1273950 This project allows for <0.1s latency: https://github.com/131/h264-live-player I use uv4l a lot, you can stream camera as well as HDMI ou...
by HermannSW
Tue Jun 18, 2019 9:41 am
Forum: Camera board
Topic: Review: Graspinghand gooseneck camera mount
Replies: 8
Views: 415

Re: Review: Graspinghand gooseneck camera mount

and I'm surprised this kind of mount isn't more popular. I am surprised as well that I have never seen it mentioned on this forum (perhaps I just missed that) as that holder is avaibale for 5 years now. On German amazon it is currently unavailable. It's very easy to flex into any position you want ...
by HermannSW
Tue Jun 18, 2019 7:31 am
Forum: Camera board
Topic: Convert MJPEG output to mp4
Replies: 5
Views: 275

Re: Convert MJPEG output to mp4

You can put mjpeg into an mp4 container with ffmpeg -r 15 -i foo.mjpg -c:v copy bar.mp4 Thanks, this works with http mjpeg stream as well (I used wget, maybe there is a direct ffmpeg way to do so as well): $ ffmpeg -r 15 -i <(wget http://192.168.178.157:81/stream -O -) -c:v copy bar.mp4 Just termin...
by HermannSW
Mon Jun 17, 2019 3:49 pm
Forum: Camera board
Topic: Convert MJPEG output to mp4
Replies: 5
Views: 275

Re: Convert MJPEG output to mp4

I'm not sure what ffmpeg options are required to achieve this, if you have had it working would you mind sharing what options you use? I tried several of the mjpeg2mp4 solutions and none worked. Then I went back to gstreamer, and was able to readout and display mjpeg stream from ESP32-CAM module Ca...
by HermannSW
Mon Jun 17, 2019 2:41 pm
Forum: General discussion
Topic: Generate multiple PWM signals
Replies: 5
Views: 199

Re: Generate multiple PWM signals

Hi. Actually the pi can generate several software PWM signals which should all you need for speed control on an L298D if you want to drive things like servos then look at joan's pigpio library, which of course you could also use to provide PWM signals to your L298D http://abyz.me.uk/rpi/pigpio/ For...
by HermannSW
Mon Jun 17, 2019 9:08 am
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 24
Views: 2309

Re: Raspberry v1 camera global (external) shutter videos

Family was out yesterday forenoon and I used our living room for new airgun pellet captures. All window shutters in living room and that in kitchen were closed, as well as room door and room doors upstairs for real darkness. After 1 hour of setting up the scene, testing, adjustment, just before new ...
by HermannSW
Sun Jun 16, 2019 10:45 pm
Forum: Camera board
Topic: Ultra high-speed imaging, capturing matrix style bullet time.
Replies: 4
Views: 673

Re: Ultra high-speed imaging, capturing matrix style bullet time.

I am not sure whether revalo still monitors this forum, you can find the wiring description in his github repo: https://github.com/revalo/pishot#gpio-based Yes, the work of revalo's team is amazing, capturing a single point in time with many Raspberry v1 cameras. You can do amazing stuff with a sing...
by HermannSW
Sat Jun 15, 2019 9:27 pm
Forum: Camera board
Topic: Convert MJPEG output to mp4
Replies: 5
Views: 275

Re: Convert MJPEG output to mp4

ffmpeg:
https://www.google.com/search?&q=conver ... mmand+line

P.S:
Off topic, I just used ffmpeg to cut out part of twitter video, and gifenc.sh to convert to animated .gif (robot's response is nice):
https://twitter.com/HermannSW/status/11 ... 0042497024
by HermannSW
Sat Jun 15, 2019 1:17 pm
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 24
Views: 2309

Re: Raspberry v1 camera global (external) shutter videos

I did a second look at 2nd global external shutter capture of pellet a 12kHz PWM frequency. I would have expected that the pellets (there are 4× more than in 1st capture with 3kHz PWM frequency) all are located on blue line because the pellet moved very fast (109.2m/s determined by 1st global extern...
by HermannSW
Sat Jun 15, 2019 1:41 am
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 24
Views: 2309

Re: Raspberry v1 camera global (external) shutter videos

My friend proposed to shoot through a stretched piece of paper and capture the pellet with v1 camera behind the paper. Of course that will reduce pellet speed, but since the pellet will create a hole that just allows the pellet to fly through, most of the oil cloud should remain behind the paper, a...
by HermannSW
Sat Jun 15, 2019 12:49 am
Forum: Camera board
Topic: Camera dropping frames, any advice?
Replies: 16
Views: 617

Re: Camera dropping frames, any advice?

I cannot see artifacts. I played with Linux "Videos" as well as with totem video player, both times more than 9s on the incrementing time display. Then I used vlc and indeed it completes faster, and does not show an incrementing seconds display. So yes, vlc does not play this video right, use anothe...
by HermannSW
Fri Jun 14, 2019 9:27 pm
Forum: Camera board
Topic: Camera dropping frames, any advice?
Replies: 16
Views: 617

Re: Camera dropping frames, any advice?

You don't say how you play the video. When I play it it shows nearly 10s length. And ptsanalyze shows 0 frameskips, and 291 frames at 30fps, that is 9.7s: $ ptsanalyze timestamp.pts 0 creating tstamps.csv 291 frames were captured at 30fps frame delta time[us] distribution 5 33324 11 33325 49 33326 1...

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