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sample/demhist.pl  view on Meta::CPAN

my $contrast = 100;
Cv->NamedWindow("image");
Cv->CreateTrackbar("brightness", "image", $brightness, 200, \&update_brightcont);
Cv->CreateTrackbar("contrast", "image", $contrast, 200, \&update_brightcont);
Cv->NamedWindow("histogram");

&update_brightcont;
Cv->WaitKey;

# brightness/contrast callback function
sub update_brightcont {
	my $brightness = $brightness - 100;
	my $contrast = $contrast - 100;

	# The algorithm is by Werner D. Streidt
	# (http://visca.com/ffactory/archives/5-99/msg00021.html)
	my ($a, $b);
	if ($contrast > 0) {
		my $delta = 127 * $contrast / 100;
		$a = 255 / (255 - $delta*2);
		$b = $a * ($brightness - $delta);

sample/motempl.pl  view on Meta::CPAN

# temporary images
my $mhi;						# MHI
my $orient;						# orientation
my $mask;						# valid orientation mask
my $segmask;					# motion segmentation map
my $storage;					# temporary storage

# parameters:
#   img - input video frame
#   dst - resultant motion picture
sub update_mhi {
	my ($img, $dst) = @_;
	unless ($start) {
		$start = gettimeofday;
	}
    my $timestamp = gettimeofday - $start; # get current time in seconds
    my $size = cvSize($img->width, $img->height); # get current frame size
	my $gray = $img->CvtColor(CV_BGR2GRAY); # convert frame to grayscale

	unless ($lastgray) {
		$lastgray = $gray;