检测图像中的马赛克检查 [英] Detecting mosaic censorship in images

问题描述

我正在尝试找出一种检测图像中马赛克检查的好方法.您知道，在哪里可以看到纯色正方形以检查照片或其他内容的一部分，例如报纸上罪犯的面孔.

现在，我不想删除审查制度，我只想检测它是否在那里.但是它也必须是可靠的.我要说的最后一件事是误报.我宁愿有假阴性(i.o.w.在没有被检测到的图像中进行检查比在没有检测到图像时进行检查要好).

我正在考虑以某种方式检测何时存在颜色均匀填充的小方块，但是对于填充颜色的大(未经审查)区域(例如天空的一部分)，这也将返回正值.我想这归结为某种模式检测，但是我不知道如何解决这个问题.

如果一开始的审查制度是完美的"，即没有JPEG伪像或其他格式错误，那是可以的.但我确实想对此做出补偿.

我们将不胜感激任何帮助:)

I''m trying to figure out what would be a good approach to detecting mosaic censorship in images. You know, where you see squares of a solid color to censor a part of a photograph or something, like the face of a criminal in a newspaper.

Now, I don''t want to remove the censorship, I only want to detect if it''s there. But it also has to be somewhat reliable. The last thing I want is false positives. I''d rather have false negatives (i.o.w. censorship in an image which isn''t detected is better than censorship being detected when there is none).

I was thinking of somehow detecting when there are small squares with evenly filled color, but that would also return positive for large (non-censored) areas filled with a color, such as a part of the sky. I guess it comes down to some sort of pattern detection, but I have no idea how to approach this...

It''s ok if at first the censorship is "perfect", i.e. no JPEG-artefacts or other malformings. But I do want to compensate for that, ultimately.

Any help will be eternally appreciated :)

推荐答案

如果您检测到一个正方形，一个完美的正方形，其颜色在可以补偿JPEG压缩的范围内，那应该工作得很好.要获得100％成功而没有误报是非常困难的，但是我认为您可能会接近.

If you detected that there''s a square, a perfect square, with colors within a range that compensates for JPEG compression, then that should work pretty well. It''s pretty hard to have 100% success with NO false positives, but I reckon you could get close.

当我发现马赛克在哪里时，这将非常有用.已经知道它在给定图片中的某个位置.如果我将完全从未见过的图像提供给算法，则基本上应该说是"或否".因此，对于具有较大相同颜色区域的图像，检测到正方形将产生大量的误报.毕竟，即使是一个圆(使用纯色填充)也可以轻松包含许多这样的正方形.

诀窍是检测正方形是否是马赛克图案的一部分，而不是根本没有正方形.一个正方形的马赛克图案不会做成;)

即使检测到多个并且要求它们具有不同的颜色并要求它们与其他物体相邻，这也不是一个好方法.考虑到如今的百万像素图片，这将是极其缓慢的，甚至除了马赛克瓷砖"的大小可以是2x2或更大的事实之外.加上它可能会产生误报，例如像一条直线，碰巧是> = 2px宽...

That would be good for detecting *where* a mosaic is, when I already know it''s somewhere in a given picture. If I feed my algorithm a totally never before seen image, it should basically say "yes" or "no". So detecting a square would generate a huge number of false positives for images that have larger areas of the same color. After all, even a circle (with solid color fill) could easily contain many such squares.

The trick is to detect if a square is part of a mosaic pattern, not if there''s a square at all. One square a mosaic pattern doesn''t make ;)

Even detecting multiple ones and requiring them to be of differing colors and requiring them to neighbour eigh other, wouldn''t be a nice way to go. It''d be extremely slow given the megapixel-pictures these days, even apart from the fact that mosiac "tiles" could be of any size that''s 2x2 or more. Plus it might generate a false positive for something as simple as a straight line that happens to be >=2px wide...

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