是否有任何工具可以等效于“ git diff”？图片（看看有什么变化？） [英] Are there any tools that can do the equivalent of a "git diff" with images (to see what's changed?)

问题描述

我正在尝试通过比较年度卫星图像来找出一种更快地确定新建筑正在发生的地方的方法。

I'm trying to figure out a way to more rapidly determine where new construction is happening by comparing annual satellite imagery.

在Google地球中，您可以回滚无论出于何种原因，都需要确定卫星图像的时钟，并确定这些年来发生了什么变化。有趣的一件事是您可以确定新的结构。目前，我是手动进行，这非常慢。

In Google Earth, you can roll back the clock on satellite imagery, for whatever reason, and determine what has changed over the years. One thing thats interesting is you can determine new construction. Currently, I'm doing it manually which is very slow.

我知道卫星照片会因天气，照片曝光量变化，季节变化等因素而有很大差异，因此我的计划是是在卫星照片上运行一些photoshop滤镜以尝试对图像进行归一化，然后运行某种差异过程以突出显示发生更改的地方。

I know satellite photos can vary greatly due to weather, photo exposure variations, seasonal changes, etcetera so my plan is to run some photoshop filters on satellite photos to try and normalize the imagery, then run some kind of "diff" process to highlight where changes have occurred.

这里是一个示例两张卫星照片，第一张于2013年5月拍摄，另一张于2015年1月拍摄。

Here's an example of two satellite photos, the first taken in May 2013, the other taken in January 2015.

如果我可以运行一些突出显示区域的过程，那将是一件很整洁的事情发生了巨大的变化，因此在这种情况下，新房屋将很容易识别e。也许在最近（2015年）的照片上输出看起来像这样。

It would be really neat if I could run some process that would highlight the areas that have changed dramatically, such that the new houses, in this case, would be easily identifiable. Maybe the output would look something like this on the more recent (2015) photo....

好吧，显然不是这样，但我认为最后一张图片概述了我的目的。

OK, obviously it wouldn't look like that, but I think the last image outlines my purpose here.

谢谢

推荐答案

不幸的是，您所拥有的两个图像上的光照差异很大。在2013年5月的图像上，它接近中午，太阳直射在头顶，意味着没有阴影-因此，当时站立的房屋实际上与周围的地面无法区分。在2015年1月的图像上，照明来自图像的底部，阴影很刺眼。因此，您所做的任何区别都不会检测到房屋数量的变化，而是会影响照明的变化。

Unfortunately the lighting on the two images you have is vastly different. On the May 2013 image it is near midday and the sun is directly overhead meaning there are no shadows - as such, the houses that were standing then are virtually indistinguishable from the surrounding ground. On the January 2015 image the lighting is from the bottom of the image and the shadows are harsh. As such, any differencing you do is not going to detect the changes in the number of houses, but rather the changes in the lighting are going to dominate.

有一个 ImageMagick 网站上名为 flicker_compare 的工具，该工具可以快速在图像之间滑动，这可以帮助您手动进行区分。我这样使用它：

There is a tool called flicker_compare on the ImageMagick website that can rapidly flick between images that may help you do the differencing manually. I used it like this:

flicker_cmp -d 100 -o animated.gif jan2015.jpg may2013.jpg

对不起，我没有其他建议。

Sorry, I have no other suggestions.

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