pi-camera | js wrapper for the native Raspberry Pi camera

For my company, we need a device to take pictures locally and store it locally as well. There are no internet or wireless connections available within this machine. This is an industrial setting where the machines (and so its control components/sensors) move a lot.

I have written an algorithm that requires images as inputs, and maps them to output values used for control commands. However, we now need to interface this software, with the appropriate hardware (camera plus computer/microcontroller) to test and use this algorithm.

Online research suggests that there are plenty of idustrial cameras with addionial software/SDKs supplied for programmable use on an arbitrary OS. However, because of our space and mechanical constraints for the camera (must fit within ~100 mm in 1 direction, must be water resistant etc.), it becomes very hard to find the right camera that fits.

Because of these limitations, our current idea is to use an (industrial) smartphone, which also yields some supplementary advantages (like additional sensors, which may be used for different applications later on). The smartphone is then connected via cable (depending on the connector a usb-c or micro-usb etc.) to a raspberry pi. We are flexible in the exact types of hardware. For example, we can buy a linux smarthpone if required, or we can use a different computer/microcontroller if needed. So the answer to this question may suggest different smartphone type and computer type if necessary.

Our current available hardware is an android smartphone and raspberry pi 2 though. And my question, based on the above assumptions, is:

Is there some software/method available that enables the Raspberry Pi to access a smartphone's camera (and potentially other sensors) such that you can control it to capture images?

The preferred programming language of use is Python, but I imagine that other languages may be required for such task.

An online search reveals that usually people look to do it the other way around: They either seek to control the Pi with their smartphone, or they access the camera wirelessly.

If anything is unclear, please suggest improvements/addtions and I will edit the question!

I am working on a project where there are 2 actions that will happen at the same time (simultaneously: stream video via pi-camera and take measurements via sensors). And I intend to draw the use case diagram of this project.
To my knowledge, the concept of parallelism does not exist in use case diagrams.
But just to make sure: Is it possible to draw synchronous use cases in a use case diagram?

I'm trying to make a live stream from raspberry to Android through the internet.

I searched through the web and I'm actually able to stream from the raspberry, and read the stream from mobile when the mobile is directly connected to the raspberry.

But if I want to make it online, there is something I'm missing on how to "pipe" this stream through another server.

So mainly I want to check how to post the stream to a server, and how to retrieve it from a mobile in realtime.

I already checked the following :

Http Live Streaming with the Apache web server

https://raspberrypi.stackexchange.com/questions/7446/how-can-i-stream-h-264-video-from-the-raspberry-pi-camera-module-via-a-web-serve

https://docs.peer5.com/guides/setting-up-hls-live-streaming-server-using-nginx/

I am trying to use the "pi-camera" library which is working and allowing me to record video in a raw h264 format on my r-pi. However, the node js library "gifify" continuously gives me the error "RangeError: Maximum call stack size exceeded" looking this error up it seems to be related calling many functions within functions multiple times or something related to this. However, my code only uses one function which contains a simple command to take the video and then convert it.

Following step 6 of Adrian's guide and some others, I managed to stream 320x240 frames with a speed of 10 fps and 0.1 s latency from my raspberry pi to my laptop. The problem is, when I test this system in my lab (which is equipped with an antique router), it can only stream 1-2 fps with a 1-1.5 second latency, which is totally unacceptable for what I intend to do with those frames.

Right now, my method is simple and straight forward: the server on the raspberry pi capture a frame and store it as a 320x240x3 matrix like the guide mentioned above, then pickle that matrix and keep pumping it over a TCP socket. The client on the laptop keep receiving these frames, do some processing on them, and finally show the result with imshow. My code is rather long for a post (around 200 lines) so I would rather avoid showing it if I can.

Is there any way to reduce the size of each frame's data (the pickled 320x240x3 matrix, its length is 230 kB) or is there a better way to transmit that data?

EDIT:

Okay guys, the exact presented length of the pickled array is 230563 bytes, and the payload data should be at least 230400 bytes so overhead should be no more than 0.07% of the total package size. I think this narrows the problem down to wireless connection quality and the method for encoding the data to bytes (pickling seems to be slow). The wireless problem can be solved by creating ad-hoc network (sounds interesting but I have not tried this yet) or simply buying a better router, and the encoding problem can be solved with Aaron's solution. Hope that this will help future readers :)