NAME
qcam, xqcam - get pictures from B&W Connectix QuickCam(tm)
SYNOPSIS
xqcam [ -pport ] [ -xwidth ] [ -yheight ] [ -ttop ] [ -lleft ] [
-sscale ] [ -Bbpp ] [ -bbrightness ] [ -ccontrast ] [ -wwhitebal
] [ -W ] [ -Eautoexposure-params ] [ -D ] [ -e ] [ -u ] [ -r ] [
-Swindow-scale ] [ -i ] [ -fconfig-file ] [ -ddump-file ] [ -H ]
[ -V ] [ -h ] [ -j ] [ -Jfile ] [ -qval ] [ -L ]
DESCRIPTION
xqcam is a program that displays the output of a QuickCam on a system
running X11.
qcam is a program that takes a single snapshot from a QuickCam, and
writes the image to standard output in PGM format.
OPTIONS
-pport Parallel port the QuickCam is attached to. The first printer
port is 0x378, the second is 0x278. Specifying a port of 0
causes qcam to "autoprobe", attempting to find the QuickCam port
automatically.
-xwidth -yheight -ttop -lleft
The QuickCam CCD is 336 pixels wide by 243 pixels high. The
above four parameters specify what part of this large rectangle
will be read and displayed. The valid ranges for top and height
are 1-243. The valid range for width is 1-336. The valid range
for left is 2-336, with the additional requirement that left be
even. The leftmost 12 pixels of the CCD are always black, so
left is usually 14 or more.
-sscale
scale can be 1, 2, or 4. It specifies what fraction of the
QuickCam data should be discarded. scale of 1 indicates that
all the data should be sent. scale of 2 indicates that half of
the pixels on each line and half of the lines should be
discarded, resulting in 1/4 as much data being transferred.
scale of 4 likewise means a fourfold shrinking in each
direction.
-Bbpp Bits per pixel. Valid values are 4 (giving sixteen shades of
gray) and 6 (giving 64 shades of gray).
-bbrightness
Exposure time. Useful values are 1-254, with low numbers
indicating short exposures (for use in bright light) and high
numbers indicating long exposures (dim light). brightness of
255 puts the Cam in "bulb mode", which is not useful with qcam
and xqcam.
-ccontrast
contrast is normally set at 104. Low numbers indicate low
contrast. Valid values are 0-255.
-wwhitebal
whitebal indicates what CCD voltage level corresponds with a
black pixel. Low whitebals make a picture dark. Normally, the
user doesn’t adjust this parameter, but does it automatically
with -W.
-W Autoadjust white balance. The QuickCam can automatically figure
out what CCD voltage value corresponds with black by looking at
those twelve leftmost always-black pixels.
-Eautoexposure-parameters
Automatically adjust exposure. -E takes from one to five
parameters. They are, in order:
mode target-lum tolerance-lum std-target-lum std-tolerance-lum
mode is an integer. Modes 0 and 1 examine the average
brightness of the picture, and adjust the brightness until the
average pixel luminance is in range. Mode 0 looks at the whole
picture; mode 1 looks at only the center ninth of the picture.
Mode 2 adjusts contrast to get the standard deviation of the
pixel luminance into range.
Ranges are specified in the next four parameters; if they are
not supplied, reasonable defaults are used.
From getopt’s point of view, -E takes one parameter. So if
you’re specifying more than one parameter, enclose the
parameters in quotes.
-e Perform edge detection. Very primitive at this point.
-D Remove dark current speckling. With a high brightness, some of
the pixels leak current even if they are not exposed to light.
-D removes these bad pixels by replacing them with an average of
their neighbors. To create the bad pixel map, run
make.darkmask, which is included with qcam and xqcam.
-u Force unidirectional port mode. qcam automatically detects and
uses bidirectional parallel ports. If your port is being
misdetected as bidir when it is really unidir, use this flag to
force the correct mode.
-r xqcam only. Release Cam lock with every scan. qcam and xqcam
lock the Cam when they use it, to ensure that two processes
don’t both try to read data at the same time. -r forces xqcam
to release the lock with each scan, so that another process can
read a frame between successive xqcam scans.
-Swindow-scale
xqcam only. Scale display window by a factor of window-scale.
For instance, if you are scanning an area of 64x80 pixels,
setting window-scale to 4 results in an xqcam window 256x320.
By default, the pixels are simply duplicated to enlarge the
window. If the -i flag is specified, the intermediate pixels
are interpolated instead.
-i xqcam only. If window-scale is set (to a number greater than
one) with the -S flag, -i interpolates the intermediate pixels
instead of duplicating them. This results in a less blocky
picture.
-fconfig-file
Read alternate configuration file. A self-explanatory
configuration file is stored in /etc/qcam.conf. Use -f if you
want to read a different configuration file. This is most
useful if you have two Cams.
-ddump-file
qcam only. Dump Cam internal information to dump-file. This
information is in a format suitable to be used as a qcam.conf
file, or it can be added to the image with image processing
tools.
-H Add histogram. A bar graph of pixel values is added to the
upper left corner of the scan.
-j qcam only. Output in JPEG format instead of PPM. Alone, this
flag will output to stdout. Not required if -J is used.
-Jfile qcam only. Output in JPEG format to the file specified. The -j
flag is not required with this.
-qval qcam only. Set the JPEG compression quality to val. The
default is 50. A higher number results in better image quality,
but larger file size. The range allowed is 1 to 100.
-L qcam only. Loop continuously. This option is really only useful
for a webcam. It currently only works with JPEGs. It will be
ignored with the default PPM output. When used with the -j
option, output will be streamed to stdout. With the -J option,
the filename specified will be overwritten each time a new image
is acquired. Use with a nph-animation server push script for a
webcam. The -L flag requires -j or -J.
-V Verbose mode.
-h Print usage information.
FILES
/etc/qcam.conf Configuration file
SEE ALSO
The QuickCam Third Party Developers web page at
http://www.crynwr.com/qcpc.
BUGS
Autodetection is very brittle.
You can have multiple Cams and multiple config files, but only one dark
mask file.
The new Color QuickCam is not handled with this software, although
there are Color Cam drivers available from the web site.
The wide-angle lens of the QuickCam gives an ugly barrel distortion.
Michael Herf has written warp(1) to fix this, but since warp(1) doesn’t
know what part of the CCD is in the image, it only works on images
whose center is the center of the CCD.
AUTHORS
Scott Laird (original code), Brian Scearce (bidirectional and dark
current modifications, xqcam window scaling, edge detection), Ed Orcutt
(autoexposure modifications), Dave Plonka (locking code).
Qcam 0.8 QCAM(1)