使用直方图确定有色物体的存在？

我正在尝试确定图片的一部分是否包含红白条纹对象（liftramp）。如果它存在，它看起来像这样：，如果不是这样的话：

I'm trying to determine if portion of the picture contains red-white striped object (liftramp). If it is present, it looks like this: , and when not like this:

天真的方法是提取直方图，并计算是否有更多的红色像素而不是蓝色/绿色像素：

The naive approach was to extract histogram, and count if there is more red pixels than blue/green ones:

use Image::Magick;

my $image = Image::Magick->new;
my $rv = $image->Read($picture);
#$rv = $image->Crop(geometry=>'26x100+484+40');

my @hist_data = $image->Histogram;
my @hist_entries;

# Histogram returns data as a single list, but the list is actually groups of 5 elements. Turn it into a list of useful hashes.
while (@hist_data) {
    my ($r, $g, $b, $a, $count) = splice @hist_data, 0, 5;
    push @hist_entries, { r => $r, g => $g, b => $b, alpha => $a, count => $count };
}

my $total=0;
foreach my $v (@hist_entries) {
        if ($$v{r}>($$v{g}+$$v{b})) { $total +=$$v{count}; }
}

然后比较 $ total> 10 （任意阈值）。虽然这对于相对阳光灿烂的日子似乎很有效（给出 50-180 存在与 0-2 不存在），重云和黄昏使得检测总是说liftramp不存在。

and then comparing if $total > 10 (arbitrary threshold). While that seems to work nice for relatively sunny day (giving 50-180 for presence vs 0-2 for not present), heavy clouds and dusk make the detection always say the liftramp is not present.

我想必须有更聪明的方法来检测是否存在红白对象。所以问题是如何更可靠地进行检测？

I guess there must be smarter way to detect if red-white object is present. So the question is how to do that detection more reliably?

请注意，灰色/绿色背景可能随着季节变化而变得更加灰褐色或类似。我也不能指望像素精度，因为它可能会移动一点（或者我只裁剪3-4像素，看看它们是否是红色） - 但它应该适合它裁剪的盒子。

Note that grayish/green background might change with seasons to more of gray-brown or something. I also cannot count on pixel precision as it might move a little (or I'd just crop a 3-4 pixels and look if they are red) - but it should mostly fit it he cropped box.