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Image autocrop
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#!perl | |
use PDL; | |
my $file = shift || 'example.jpg'; # if no argument is passed use example.jpg | |
my $thres = 0.40; | |
# chopping the file path ... | |
my $s = rindex($f,'/'); | |
my $fpath = ($s > 0) ? substr($f,0,$s) : '.'; | |
my $filename = substr($file,$s+1); | |
my $p = rindex($filename,'.'); | |
my $basen = ($p>0) ? substr($filename,0,$p) : $filename; | |
my $ext = lc substr($filename,$p+1); | |
#printf "%s %s %s %s\n",$fpath,$filename,$basen,$ext; exit; | |
my $cropfile = "${basen}_cropped.$ext"; # results | |
my $yc = pdl( [.299,.587,.114] ); # primaries sensitivity coefficients ... | |
our $pix = inner($yc,rpic($file)); | |
my ($xsize, $ysize) = dims($pix); | |
printf "%s: %ux%u\n",$basen,$xsize,$ysize; | |
# --------------------------------------------- | |
# use the average brightness to determine ROI | |
my $level = avg($pix) * $thres; | |
my $mask = $pix>$level; | |
use PDL::Graphics::Gnuplot qw(image); image $mask; | |
my ($xmin,$xmax) = (undef,undef); | |
my ($ymin,$ymax) = (undef,undef); | |
# --------------------------------------------- | |
for my $j (0 .. $ysize-1) { | |
my $k = $ysize-1 - $j; | |
#printf "row%u: %u\n",$j,nelem(which($ppm->slice(":,($j)"))); | |
if (! defined $ymin && nelem(which($mask->slice(":,($j)"))) ) { $ymin = $j; last if defined $ymax; } | |
if (! defined $ymax && nelem(which($mask->slice(":,($k)"))) ) { $ymax = $k; last if defined $ymin; } | |
} | |
for my $i (0 .. $xsize-1) { | |
my $l = $xsize-1 - $i; | |
#printf "col%u: %u %u %u\n",$i,nelem(which($ppm->slice("($i),:"))),$xmin,$xmax; | |
if (! defined $xmin && nelem(which($mask->slice("($i),:")))) { $xmin = $i; last if defined $xmax; } | |
if (! defined $xmax && nelem(which($mask->slice("($l),:")))) { $xmax = $l; last if defined $xmin; } | |
} | |
# --------------------------------------------- | |
printf "y: min=%u, max=%u\n",$ymin,$ymax; | |
printf "x: min=%u, max=%u\n",$xmin,$xmax; | |
my $ROI = sprintf '%u:%u,%u:%u',$xmin,$xmax,$ymin,$ymax; | |
my $cropped = $pix->slice($ROI); | |
wpic($cropped,$cropfile); | |
exit $?; | |
1; # $Source: /my/perl/scripts/at/ACE/autocrop.pl,v $ |
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