New camera project! Need help with a few things...
 

Hi all,

I'm glad to say I'm back with a brand new camera project! No industrial cameras, no demo boards, no minipcs. Just a 1920x1080 CCD sensor and FPGAs recording DNG sequences to a compact flash card. I can say little more about it because there's little more to say. Do I have the resources to do it? Yes, but I need your help to start it. Don't worry. I won't ask for money...

First of all I just need to know what would be the standard complete diagram with all hardware needed to go from the sensor to the flash card (including LCD output). Here's what I need:

- A/D conversion from the sensor.
- Basic sensor control. Shutter, fps, ISO, frame height/width... For now I don't need to know HOW to do it. Just the hardware I'd need to do it.
- DNG sequence conversion from the digital stream.
- Standard LCD out.
- Probably DVI out for monitoring.
- Of course, compact flash out.

Extra questions:

- Can everything I need be implemented into ONE FPGA?
- What other features would you add (appart from audio recording) to a basic digital cinema camera?
- Would it be possible to add pro quality audio recording?

I'm accepting all kind of suggestions on hardware, advices to design a speed/energy efficient system...

Thanks a lot in advance. It's good to be back!!

I've got another question for people interested in sensors. I've got a few initial choices for fullHD or 2K CCDs (I want global shutter) but they're mostly 2/3" sized. Not bad. Many digital cinema cameras have them, but I'd like something a bit larger. What are my options for a good quality fullHD/2K 1", APS-C or full frame sensor? I know there won't be many of those out there but, I'd like to know if I've got other possibilities. Even if they're CMOS.

Thanks again.

More questions. The camera will store the frames in DNG format and it's suposed to deliver up to 60fps FullHD. Will a fast compact flash card be fast enough to do it? Do you think an internal HDD is a better option?

Thanks.

the a/d is always included on the sensor.

DNG is basically TIFF with some special tags, which would be a pain to write in hardware. if you really want a ginormous sequence of DNG's out of your camera (remember DNG's are for still images not video), it's far easier for your camera hardware to write raw bayer data to flash, then wrap and convert those frames to DNG, or whatever format, upon flash ingestion with software running on your workstation.

Even in CCDs?

I've been following the video DSLR subject lately, but always interested in these DIY experiments. Best of luck with your project Jose.

Go for the Sony 24 Mpixel full 35mm CMOS.
It is fast, it's full size, and because you won't be using the full resolution it should give you the required framerate.

Sony Global - Press Release - Sony Develops 35mm full size CMOS Image Sensor with 24.81 Effective Megapixel resol

I don't remember it's number code, but I remember that is was around $400 dollars each if you are buying just one.

Good Luck

Don't get me wrong but i have to ask 'why?' (and i love these threads too). I've personally dabbled with machine vision heads and piecemeal collections of bits and pieces and i've learnt lots about what goes into these things. So beyond the education aspect (which is reason enough to do it) are you looking to do this commercially? If so, isn't this exactly what ikonoskop have done?

I believe they are using one of the new kodak quad tap CCDs which should be available around now. I've used the previous generation (the KAI 2093) which was good but suffered vertical blooming too much for my tastes.

I don't think that sony 35mm would do (plus sony of all people aren't about to release a sensor that would cripple their video camera sales - the industrial vision sony CCDs, which are great quality, are all sub 1080 resolution)

And DNG is a valid way of storing the files, the white papers for cinema DNG are on the adobe site somewhere and feature meta data for black balancing, bad pixel mapping and other variables useful for moving image sequences.

cheers
paul

Paul,

Not trying to say your points are invalid, since they are very understandable. But it would be nice to see a camera that is open source/ publicly developed right here. I think it's healthy to get these kind of thoughts out in the open for discussion.

I think in the true spirit of creating something it's best to stay away from the "why" question and just enjoy the discussion, if for nothing else "the education aspect [is reason enough.]"

Sony does have their occasional schizophrenic moments. They sell software that can rip cd's but then they were trying to push DRM and the like. You never know.

The real sad part about sensors in general though, seems to be that manufacturers are always trying to push pixel count and the sensors are only a larger format to add to the count. The ideal sensor would have larger, more sensitive pixels, like a 2MP 1" sensor.

Why? Why not?

I mean, you can choose from a huge number of different options if you want to buy a simple camcorder, a photo camera, a computer, a dvd player... If you want to buy an affordable digital cinema camera you've got what? 3 options? 5 by this time next year? The more options you have, the more possibilities you have to find exactly what you want.

So...

- The camera will have either a 1,2" 2048x2048 CCD or a 2/3" 1920x1080 CCD both by Kodak. Of course if it's the first one, this camera will have an interesting point against other 2/3" cameras.

- I need someone who can confirm that DNG is a good format for the image sequence and if a fast compact flash card will be able to store that sequence at 60fps. If not, at least at 25fps. What would be the frame size in FullHD?

- Do new CCDs have a built in A/D converter?

I'll try to post a basic diagram tomorrow, so I can tell you exactly what I want and you can say what's missing, what's wrong and what can be improved. It'd be great if someone could answer my questions...

Ok, I couldn't wait. Here it is...

What's missing? What can be improved? What's wrong?

And...

- Which FPGA to use?
- Flash cards or internal HDD?

Thanks a lot.

Well, you're probably big enough to do the math by yourself since we're talking about raw data here (and it's been repeated countless times in every single camera thread in this forum).
Here, just for you : 1920x1080x10x24 = 60MB/s
Fastest CF card is around 40/45MB/s, and that's if you can access it in UDMA mode... Not to mention that writing a lot of small files instead of one big reduce the performance _a lot_ on flash drives.
Had a look at the latest SSD drives ? Some are around 80/90MB/s (or more ?) in writing speed...

Read the specs, luke. (AFAIR, the KAI-2093, yes)


Basically you want an elphel camera with a CCD sensor.... save you the hardship to redevelop the whole thing.

Hi steven,

Thanks for the maths and the answer for the A/D converter. Those numbers are for raw data but is it the same for DNG files?

I've already considered SSD disks. It's probably the best option.

No, I don't want an Elphel. I want to build a pc-less camera with its own lcd and controls.

Jose,

Once i posted my comment i was a bit concerned about being overly negative, my aim was perhaps to avoid a lot of expense for you in re-inventing the wheel.

Your aim is pretty much identical to ikonoskop and their camera ships soon and doesn't seem that expensive, although they have had to make their own solid state storage to handle the demands of 60fps RAW DNG files.

Your biggest problem with a sensor over 1" will be lenses. There are very few good lenses with that coverage. There are some fujinons with an image circle that size but you'll miss out on all 16mm and S16 lenses out there. You can convert APS-C style lenses but you'll miss out on fast and wide choices. If you want to make a camera that can actually be used for shooting you need to be able to focus on the run, the lens is key to this. Machine vision lenses are *not* ideal for this (this from experience). I would stick to 2/3rds sensor size if i were you.

Also performance wise one of the biggest differences between available CCD sensors and those sensors in high end cameras is vertical blooming. The Kodaks are okay but not good enough (imho) for practical use outside out and about. I cannot comment about the new generation though and they may be good enough now (the quad tap ones). Sony have some fantastic sensors with FIT but are not available (they're the ones used in their cameras). The only good sony ones available to buy are lower resolution and 4:3

If i were you the first thing to check would be the availabily of lenses that would work for you and also the performance of the new kodaks with regards to vertical blooming.

I think your only practical CCD choice is that new 1080p Kodak quad tap sensor...

cheers
paul

Hi Paul,

Thanks for your answer.

I know this project looks pretty close to what an Ikonoskop camera will offer soon, but as I said, appart from the educational value, i can't see the problem in having many options to choose from. In fact, there're SSD disks out there with 90Mb/s sustained writting speed for about $400. Without the need to develop a new storage card, this camera will probably end up being cheaper.

About the lenses questions, I know there're many good quality and cheap machine vision (fujinon, computar...) and s16mm old lenses out there for a 2/3" sensor. I started gathering info about the 1,2" CCD because I saw what the NoX camera from GS Vitec can do appart from the shallower DOF. You're also forgetting the new Micro 4/3 format. Those lenses cover about a 18x18mm area, that's only 3mm more than the 1,2" sensor and they're photo lenses. In terms of focus, it's like working with a 35mm adaptor.

What do you think?