Re: Mac Microscopy Advice

Gary G wrote: 
On 30 Jan 2006 23:20:03 -0600, Aaron <nghy@xxxxxxxxxxx> wrote:


No doubt the Pixera is a wonderful camera but it is typically slow
producing high frame rates at full resolution.  This is not peculiar
to Pixera it is true for all cameras in that resolution range.

Also check out 

http://1stvision.com/cameras/cameras.htm

for a range of proffesional grade c-mount video cameras.

With today's technology, 1.5 mega pixels is the point where digital
cameras that record motion meet a barrier. To record motion smoothly
requires 30 frames/sec. At 1.5 megapixels, few cameras deliver 30
frames/sec. Typically, digital motion cameras can handle VGA (640 X
480) or almost SVGA (800 X600 pixels). The new digital cameras are
just surpanting medical grade analog video cameras that have
resolution in the 0.4 megapixel range. .

So there is a conflict between high resolution and realtime recording
of motion. At five megapixels resolution, even the best digital
cameras have trouble with five or ten frames per second.. In addition
to the CCD chips having trouble sending the data, the high data
transmission rates tax the computer system's ability to record and
display that much data. A typical laptop is not the most powerful
computer and so there are further compromises to be made between being
able to capture motion in realtime and handling truly high resolution
digital images in the 3 to 12 megapixels.range.
. 1st Vision specializes in cameras designed for machine vision
applications and motion analysis. They are c mount and incorporate
high data transmission hardware protocols such as USB 2, Firewire, and
Gig-E (Gigbit ethernet). . Aaron 

On 30 Jan 2006 17:32:35 -0800, just_golfin@xxxxxxxxxxx wrote:


We're looking for a scientific grade camera, as opposed to a consumer
one.  Can you do real time on-screen capture and manipulation with a
consumer digital, without swapping memory cards?  I didn't think this
was possible and we want high resolution.  This will be in a vet school
setting.  Thanks.




The fps of the camera is very dependent on the link to the PC and the
speed of the PC.  At 1GHz P4, I get about 15 fps.  With 2.8GHz P4, it
is more like 60fps.  This is in preview mode at 640x480.  This could
be captured in real time at this resolution.  But if you want higher
pixel density, it won't be real time.  It will be fast but not
streaming.  The Pixera 150-series will do single shot captures from
1/1000 second to 60 seconds.  But even at the fastest capture, it
takes time for the camera and control card to process the capture and
finally present it as a final image.  That can take two to three
seconds to complete.

So, are you looking for streaming capture or snap capture?  If snap
capture, you can do that but it takes a couple of seconds before being
able to do it again.  Plus, if you store in TIFF or JPEG, there is
time for transferring to disk.  If you have slow disks, that too is a
bottle neck.


A possible alternative path.
I've recently suffered thru many ads for HDTV capable sattleite TV ads for service which includes DVR with 100 hr record capability and real time pause/replay capability.

So how about

                                 +---> Monitor
                                 |
Camera --> Black Box  --> DVR  --+
                                 |
                                 +---> Computer for image manipulation

Image manipulation process is unlikely to be real time and the DVR would be still recording the incoming frames while paused to send desired frame to computer.

As to "Black Box", you mentioned "vet school setting". Does that imply you might be in or near to a university with an Electrical Engineering department. Forty years ago I was an electronics tech at a vet school which had a fruitful relationship with local EE's.
.

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