webcam(1)						      General Commands Manual							 webcam(1)

NAME

       webcam - capture images and upload them to a webserver using ftp

SYNOPSIS

       webcam [ config file ]

DESCRIPTION

       webcam captures images from a video4linux device like bttv, annotates them and and uploads them to a webserver using ftp in a endless loop.

CONFIGURATION

       At startup webcam reads the configuration from the given config file or ~/.webcamrc if none is specified in the command line.

       The  config  file has at least two sections.  The "grab" section holds the capture parameters.  Any other section describes where the image
       should be uploaded.  Older versions used "ftp" as name for that section.  Recently the webcam utility got support for multiple connections,
       thus  any section name is accepted and you can have more than one ftp section (you have to use another name for each section througth, name
       them by upload servers for example).

       Here is an sample config file (the given values are the defaults):

       [grab]
       device = /dev/video0
       text = "webcam %Y-%m-%d %H:%M:%S"
       infofile = filename
       fg_red = 255
       fg_green = 255
       fg_blue = 255
       width = 320
       height = 240
       delay = 3
       wait = 0
       input = composite1
       norm = pal
       rotate = 0
       top = 0
       left = 0
       bottom = -1
       right = -1
       quality = 75
       trigger = 0
       once = 0

       [ftp]
       host = www
       user = webcam
       pass = xxxxxx
       dir  = public_html/images
       file = webcam.jpeg
       tmp  = uploading.jpeg
       passive = 1
       debug = 0
       auto = 0
       local = 0
       ssh = 0

       The annotation text is processed with strftime.	Check the strftime(3) or date(1) manpage to see how you can format  the  timestamps.   The
       text  can  also	be  read  from	a extern file (use infofile for that).	The default color for the text overlay is white (RGB=255,255,255).
       Entries in the range of 0 through 255 for fg_red, fg_green, and fg_blue can  be	used  to  define  a  different	color.	 Likewise  bg_red,
       bg_green, and bg_blue can be used to set the background color (which defaults to transparent).

       input  is  the video source (TV/composite/whatever), norm the TV norm.  delay is the delay between two images in seconds.  wait is the ini-
       tial delay before the first image is grabbed (some cameras need some time for adapting to lightning, thus don't return images with  reason-
       able quality within the first few seconds ...).	quality is the JPEG quality for the stored images.

       top,  bottom,  left, and right in the grab section allow cropping the image after it is grabbed.  They should satisfy 0<=top<bottom<=height
       and 0<=left<right<=width.  (0,0 is the top, left corner.)  If rotate is positive, the output image will	be  rotated  counter-clockwise	90
       degrees that number of times (1, 2, or 3).

       With trigger set to a non-zero value webcam will upload the image only if the content of the image has changed.	It just looks for the max-
       imum difference between the last uploaded and current image and if it is greater than the specified value the image will be  uploaded.	If
       once is set to 1 webcam will upload a single frame and quit.

       archive	can  be used to create a (local) archive of the webcam images.	Just specify the filename for the files as argument.  The filename
       will be processed with strftime(3), so you can use the place the usual time format controls into the string to get unique filenames.   Non-
       existing directories are created if needed.

       If  debug  in the ftp section is set to 1 the complete communication between webcam and the ftp utility is printed to stderr.  auto enables
       autologin via ~/.netrc (starts the ftp utility without the '-n' switch, check the ftp(1) man page for more info about the  ~/.netrc  file).
       If local in the ftp section is non-zero, files will be stored locally (using the dir, tmp, and file parameters) rather than ftped.  ssh set
       to non-zero makes webcam use ssh instead of ftp.

CORRECTION OF DISTORTION

       contributed by Frederic Helin, the parameters belong into the [grab] section of the config file too.

       distor = 1
	      If distor param is set to 1, the correction of distortion works.

       distor_k = 700
	      This is the coefficient of distortion. This algorithm is based on the paper "Correcting Distortion of Image by  Image  Registration"
	      of  Toru Tamaki, Tsuyoshi Yamamura and Noboru Ahnishi. More your lens has an important distortion, more 'distor_k' must be neared of
	      0. 700 is the default value. Coefficient k of program is x100 than article.

       distor_cx = 192

       distor_cy = 144
	      Coordinates of the lens optical axis: width/2 and height/2 are the default values. The axis doesn't go through the image center. So,
	      you can change its coordinates around the center of image to affine correction.

       distor_zoom = 30
	      Zoom parameter is used to cache the distorted borders of image, if you don't like this. Default value is 100.

       distor_sensorw = 320

       distor_sensorh = 240
	      Dimensions of camera sensor. Default values are for 1/4p sensor. This parameters used to have the same k coefficient than article.

AUTHOR

       Gerd Knorr <kraxel@bytesex.org>

COPYRIGHT

       Copyright (C) 1997-2002 Gerd Knorr
       This  program  is  distributed  in  the	hope  that  it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MER-
       CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

							     (c) 1998-2000 Gerd Knorr							 webcam(1)