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lib/AI/MXNet/Image.pm  view on Meta::CPAN

{
    if(defined $self->seq)
    {
        return undef if($self->cur >= @{ $self->seq });
        my $idx = $self->seq->[$self->cur];
        $self->cur($self->cur + 1);
        if(defined $self->imgrec)
        {
            my $s = $self->imgrec->read_idx($idx);
            my ($header, $img) = AI::MXNet::RecordIO->unpack($s);
            if(not defined $self->imglist)
            {
                return ($header->label, $img);
            }
            else
            {
                return ($self->imglist->{$idx}[0], $img);
            }
        }
        else
        {
            my ($label, $fname) = @{ $self->imglist->{$idx} };
            if(not defined $self->imgrec)
            {
                open(F, $self->path_root . "/$fname") or confess("can't open $fname $!");
                my $img;
                { local $/ = undef; $img = <F> };
                close(F);
                return ($label, $img);
            }
        }
    }
    else
    {
        my $s = $self->imgrec->read;
        return undef if(not defined $s);
        my ($header, $img) = AI::MXNet::RecordIO->unpack($s);
        return ($header->label, $img)
    }
}

method next()
{
    my $batch_size = $self->batch_size;
    my ($c, $h, $w) = @{ $self->data_shape };
    my $batch_data  = AI::MXNet::NDArray->empty([$batch_size, $c, $h, $w]);
    my $batch_label = AI::MXNet::NDArray->empty(@{$self->provide_label->[0]}[1]);
    my $i = 0;
    while ($i < $batch_size)
    {
        my ($label, $s) = $self->next_sample;
        last if not defined $label;
        my $data = [AI::MXNet::Image->imdecode($s)];
        if(@{ $data->[0]->shape } == 0)
        {
            AI::MXNet::Logging->debug('Invalid image, skipping.');
            next;
        }
        for my $aug (@{ $self->aug_list })
        {
            $data = [map { @{ $aug->($_) } } @$data];
        }
        for my $d (@$data)
        {
            assert(($i < $batch_size), 'Batch size must be multiples of augmenter output length');
            $batch_data->at($i)  .= AI::MXNet::NDArray->transpose($d, { axes=>[2, 0, 1] });
            $batch_label->at($i) .= $label;
            $i++;
        }
    }
    return undef if not $i;
    return AI::MXNet::DataBatch->new(data=>[$batch_data], label=>[$batch_label], pad => $batch_size-$i);
}

1;