Built-in camera


#1

I have just joined this project however I have just a question regarding the on-board camera.

I am building my own version with a little bit different parameters.

The one I have been working on must be able to dive much deeper, down to 150 meters at least so I am well aware of water problems and propulsion. Since my current project has a little different approach and also a different budget, I am not sure that I can be of help regarding propulsion or water proofing but what I can add is my knowledge of video.

I have noticed that you are working with a USB camera via the on-board MPU. I am not surprised that the images are sluggish and that problems occur so I have another idea that will solve a lot of problems in this regard.

It's not as cheap as a low-cost USB-camera however the cost difference isn't huge and the advantages is well worth it.

I have been working with a digital transfer via a so called SDI interface. A standard in the professional TV world that now have been entering also the surveillance marked. The advantage is that is can either use a thin coax cable suitable for theaters for as long as 60-100 meters without any special demands of the coax except the impedance and still provide full-HD images in real-time, OR use a high quality coax cable and reach around 300 meters with full-HD and real-time transfer.

This way a "normal" SDI surveillance camera with full-HD and SDI-HD interface can be used inside the ROV. The cost of such complete camera is only around $75-100USD, sometimes even lower. It isn't a "budget" alternative however there are several advantages. The major advantage, except real.time HD is also that its a official standard, it doesn't need any CPU power and with the right camera, the images can be controlled via a standard RS485 interface which is very easy to control via a MPU or from the surface directly. Another big advantage is that the cameras bot only have a higher quality but also usually better in low light conditions, have a automatic LED control (built-in are usually IR but this can easily be changed to white LED's), a lot more image adjustments, and so on (and they are also many time IP66 water proofed, not that this will make them suitable to be placed outside but they provide a extra layer of protection inside the ROV shell.

Via a simple overlay video mix, the ROV data can be overlay''d on-top of the video images, hence giving a full feedback of the ROV's pitch, yaw, speed, depth, etc, etc.

So my question is that, is there shear lack of knowledge of any particular reason why this haven't been entered as at least and alternative?

If this is a alternative that is of interest, just contact me via this page or on my mail address: johan@acquris.se so I can provide more information if needed...

Best regards

Johan Öhgren

Sweden


#2

I'm interested. Please post more info!


#3

Hey Johan,

Thanks for the comment! You're right on!

I'm not sure if you've had a chance to play with the latest version of the software, but we're now getting full-HD video with little to no lag. The biggest issue was with tether, and the new homeplug adapters are allowing us to send up to 100mb through a twisted pair. I'll try to post a video that shows the improved quality.

Heads-up GUI is a great idea, too. The first step is integrating the sensors needed to gauge yaw and depth.



#4

By "thin coax" what exactly does that mean? How thin and how flexible? Also, what about its neutral buoyancy characteristics?

The coax cable that I'm familiar with is quite thick and non flexible. The 2-wire tether that I got with my OpenROV is quite flexible and thin.

-Marcus