jeffbass
commented
3 years ago Hi Claude @pageauc, Glad you love my project. Thanks. Your project sounds really interesting. I'll definitely keep an eye on it on GitHub as you make progress.
Regarding your text sending question, I do use imageZMQ to send and receive text messages in a number of my projects, using the ImageSender.send_jpgmethod. The jpg_buffer can be any bytestring; it doesn't actually have to be a jpg. To use imageZMQ to send text messages only, I just set the jpg_buffer to a short bytestring in the sender. Then I receive and ignore that short bytestring in the hub that receives the text message. For example:
# Sender that sends text messages
# in the text sending program, where sender is an imageZMQ.ImageSender instance
msg_text = 'Some message text.'
hub_reply = sender.send_jpg(msg_text, b'0') # set jpg_buffer parameter to a single byte
# Receiver that receives the text messages
# in the text receiving program, where hub is an imageZMQ.ImageHub instance
msg_text, buf = self.recv_jpg() # buf contains b'0', but just don't bother to use it
# or, another way to not use the jpg_buffer that is received.
msg_text, _ = hub.recv_jpg() # another way to receive and not use the jpg buffer
This code works well for me in a number of my projects. I do sometimes have to use the text.encode and byte.decode methods to avoid errors about text versus bytestrings in my message text:
# convert bytes to Python 3 string:
mst_text = msg_text_in_bytes.decode('utf-8') # decode from bytes to Python 3 string
# or, converting from Python 3 string to bytes:
msg_text_in_bytes = msg_text.encode() # convert Python 3 string to bytes to make ZMQ happyYour method of using config.py text files and a watch program to control startup and options of your cameras versus the hub sounds similar to what I am doing with my imagenode and imagehub programs. I have a threaded function that watches for imagehub restarts (or other glitches) and it then restarts the imagenodes accordingly. To change the imagenode settings (there are many of those!), I copy a new imagenode.yaml text file to the imagenode and restart it. I use systemctl for starting and restarting my imagenodes using an imagenode.service file. You can see that in my imagenode repository here. My approach to the fact that hubs have to start before senders is to have all my imagenodes running continuously as systemctl services with the (Restart=always, RestartSec=5) options. Then, whenever the imagenode detects an imagehub restart, it simply exits. Then systemctl waits 5 seconds and restarts it.
Thanks for sending your RPi camera stand template. I'm going to give it a try. No need to apologize for being chatty. I love to hear about the projects that benefit from imageZMQ. I learn a lot from what others are doing. It is why I find GitHub so useful.
Jeff
pageauc
Jeff. Love your project. I am working on a project that uses multiple RPI 's with camera's could be webcams as well. The hub program starts and waits for the currently three sender RPI's to send an image. Each image is saved with a sequence number. The hub then sends each sender a timestamp for the next timelapse to be taken. This will be identical for each sender. The hub then does an image stitch to make a pano image and saves with sequence number then increments for next cycle. This is all working well although I had to make custom camera mounts out of foam board, small block of wood and a short dowel.
The problem I have is that the hub Must start before the senders. I want to automate the system so I was thinking of setting up a watch program on each sender that listens on another port. When the hub is started or restarted it sends each sender watch program a new python configuration file of settings eg resolution via zmq. Watch saves File as a config.py. Watch program then starts/restarts the sender program in background via subprocess Popen. Sender then restarts and reads the new config.py as an import. Still working on this.
Would it be possible to send a text file and return a confirming text message between the hub and sender rather than a jpeg and text per imagezmq. Currently I was looking at just using basic zmq commands to the hub and watch program on the senders but would be nicer if it was possible with imagezmq. Could not find this feature in imagezmq code but thought I would drop you a line.
Note I had to modify the https://github.com/ppwwyyxx/OpenPano c++ code to get it to accept an output file path for the pano jpg/png since it would only generate a fixed out.jpg named file in the same folder. My version is here https://github.com/pageauc/OpenPano. Created curl bash scripts for easier install. I could have used Adrians opencv image stitching but prefer the self contained openpano approach since users would not need the latest/greatest opencv contrib version.
FYI I have attached my camera holder template in pdf format. When the pipano project is ready I will post on my GitHub repo. Still a work in progress. There are lots of issues to work out. For one, the cropping of pano's is not consistent so doing a timelapse video would need some image stabilization during video editing or pruning some images. If lighting is stable then most of the pano's crop pretty consistently but low light can throw things off easily. I had to build the stands to allow accurate pointing. Don't want to use a pan/tilt mechanism because images would not be synchronized with same timestamp. Might add pano stitch to my robot as a feature since full view would be in one stitched image.
my pano stand. Currently have three on a board with various holes space around for stand dowels to fit into. Then rotate (pan) via dowel point and tilt via side lower hinge leg screws. This works quite well and easy to mount on a fence or even a vertical surface as long as you don't mind a small hole at mounting point
[cam-stand.pdf](https://github.com/jeffbass/imagezmq/files/5180357/cam-stand.pdf
Excuse me if I got a little chatty Claude ...