Any Way to Autojoin Images From Multiple 4MP or 8MP Digital Cameras?

I have a fixed position application that requires top down macro pictures of
printed circuit boards. From a previous thread, it appears that even a 12
MP camera may not be enough to cover the area I need covered with sufficient
detail. We aren't budgeted for a good 12 MP camera unfortunately.

Does any vendor make a 4 MP or 8 MP camera that can be mounted in either a
pair or quad configuration, together with software that will coordinate
taking pictures will all cameras simultaneously then autojoining them into
one larger image? The application would probably require a stand that
allowed for the mounting of multiple cameras pointing down.

 

If I remember correctly, you earlier specified a maximum board size of a
foot square. You shouldn't need a 12 MPixel camera for that, but it
depends on what you want to resolve. I guess the worst case would be a
populated board with surface-mount components as small as
rice-grain-sized resistors (I forget their wattage at that size).

For interest I shot an old computer mainboard measuring about 9 inches x
12 inches with a Canon 300D 6.3 Mpixel camera and a 17-85mm zoom lens.

That lens is by no means optimal for this application, but nevertheless
it resolved the values printed on the SM resistors, like 221, 103, etc,
and of course IC markings, as well as tracks and silk-screened board
markings.

I would think that a Canon 350D or 20D, with an 8 megapixel sensor and a
genuine macro lens - not a zoom macro - would be considerably better
than my camera, and would do the job.

Depending where you are located, you may be able to rent a 350D and
macro lens for trial.

A proper macro lens is desirable, as it will be rectilinear, that is,
straight lines will be rendered straight, without the curvilinear
distortion exhibited by zoom lenses, as well as being corrected for
close distances.

Colin

 

It's been mentioned that the macro-designated lenses are expected to
perform well "flat field", and a circuit board is probably pretty
close to that.

If it turns out to be true that you need more than one 8MP image to
cover the board successfully, and do need to join multiple images, I
wonder why you need them made simultaneously. It should be relatively
easy for an engineer to come up with a template to guide placement of
the board for consecutive images that would include the whole board in
four shots. Elapsed time between shots couldn't be more than a few
seconds, and location very consistent, in those circumstances. With
practice, and perhaps computer control, four exposures ought to be
accomplished in five seconds, don't you think?

 

You got me interested, so I grabbed my 8Mp prosumer (Oly C8080), and
ran off a very crudely lit (on-camera flash- yeeuch!) image of an old
decrepit 386 mobo I had lying nearby. The mobo is about 12" x 10".
Here is an actual-pixel-sized crop of the outermost lower-right corner
of that image - the crop represents about 2.5 x 2.2" of reality.. I
thought I would show you that area as it should represent the worst
lens performance, and please pardon the noise, I souped it up and
over-sharpened!

http://image44.webshots.com/44/5/15/83/353651583UVTwob_ph.jpg

Here is the full (but NOT full-res, see below) image for comparison:

http://image38.webshots.com/38/5/46/54/353654654KoPhDj_fs.jpg

BUT, bear in mind I had to resize the second shot down from 3264 pixels
wide to 2400 to comply with webshots requirements. It still gives a
fair idea of resolution, but use the crop to get a better idea..

I find it pretty easy to read all the stuff on there and with better
lighting and more care in shooting (and also taking into account these
shots were contrasted up and jpegged) you should be able to achieve
better performance, but probably not much. The Oly C8080 has one of
the best, if not *the* best, zoom lenses in this category of camera, by
the way.. For what it's worth, it was shot at about 50mm zoom
equivalence, hand held from a couple of feet away. Hope this helps to
give you a baseline.

Again there is the stitching issue, but you might want to investigate
the costs of A3 scanners.. might work out cheaper than two digicams,
would certainly solve the resolution problem... Make sure it isn't an
'LIDE' type scanner, as these have almost zero depth of field.

 

Depending on your needs, a program like AutoStitch (designed for making
panoramas) may do:

http://www.cs.ubc.ca/~mbrown/autostitch/autostitch.html

David

 

I grabbed my 8Mp prosumer (Oly C8080), and

Sorry, links to full images don't appear to work. If you are still
interested, go here and then you have to click on the "View Full Size"
link to see the full images..

Crop:
http://community.webshots.com/photo/262782767/353651583UVTwob

Full-frame:
http://community.webshots.com/photo/262782767/353654654KoPhDj

(for anyone who is not following the thread, these are boring, noisy,
poorly lit images of an old circuitboard - please do not judge my
abilities on them.. (O

 

Also the macro lens will be equally sharp in the corners and center.

This makes sense and easier to group the images for panorama stitching.

 

Not exactly what you're looking for, but along the same lines,
especially in terms of automated stitching:

<http://www.ecs.soton.ac.uk/~km/projs/vasari/>

Maybe it'll give you a few ideas.