NEW ELPHEL 323 SOFTWARE
The 323 camera uses an 11MP interline transfer CCD.
This and its accompanying Elphel hardware make it an
ideal platform for a variety of image-quality-critical
applications in which instant triggering and silent
operation are required. However, the existing software
was not designed for this application, and the
following outline the major areas needing new work.
This is for a 323 equipped with dual compressor boards.
Raw + small JPEG. This combination is nearly standard
for any image-quality critical photography. The raw
format should be Adobe DNG,
http://www.adobe.com/products/dng/main.html, which is
Also, EXIF data should be added to both files,
including time, date, gains, integration period, Vsub,
Dark frame subtraction: A frame taken with all the same
parameters as the target frame (but without light,
either due to a mechanical shutter or illumination
switched off). Subtract the dark frame on an individual
A smear frame is similar, but the continuous lighting
is kept the same, and the electronic shutter used for a
vanishingly small period. The resulting image is the
result of light leaking into the transfer cells on the
The KAI-11000 CCD is capable of starting integration
within 10 microseconds. The external trigger, which may
enter through spare pins on the sensor FPGA, should
come close to this.
Also, the camera should output a signal corresponding
to the integration time. High while integrating, low at
all other times (or the inverse logic). This can be
used for flash sych directly, and for synchronization
with external data acquisition.
When waiting for the trigger, currently input into CTS1
on the master Axis chip, there should be a programmable
period after which the analog voltages on the sensor
board are powered down. This is currently in units of
milliseconds counted in a 16-bit register. Prior to
triggering, a half or even full second to turn-on time
to initialize the CCD is perfectly acceptable for
current applications. An option to have it stay awake
indefinitely should be available.
Also, there should be an option to rearm the trigger so
that a new image is acquired on every CTS1 activation,
provided that the existing image is already downloaded
to the client.
A Firefox plugin that combines image halves from
multiple cameras that are triggered either
simultaneously or within milliseconds of each other.
This should include RGB and luminance histograms, and
camera parameters. The channel gains should be
configurable as exposure, white balance, white and dark
points, and center sliders. When enabled with a
checkbox or single keystroke, write the image(s) to a
file with sequential numbering.
WINDOWING FOR FOCUS
A designated small square, a subset of the full frame,
should be displayed on the client with a fast
frame-rate (i.e. like video) for focusing.
REQUEST FOR PROPOSALS
This can be a paid project. Candidates must either have
access to a 323 or must be located in the San Francisco
area. Reply with resume and other pertinent information
to bernard at bear inc dot c o m. The timeframe is