分类： Uncategorized

本篇内容引自豆瓣绮玛蓝的日记，转在这里防止被删。

奈飞的电视剧《三体》一开场就是炸裂的场面，导致有人说这是奈飞抹黑。

而实际上，在这个情节上，奈飞非常尊重原著： 继续阅读有奶便是娘的爱因斯坦

继续阅读当法律遇上陋习

SSH login is supposed to be fast – All it needs are a key exchange to establish a secure channel and then an authentication process, which are both trivial tasks to modern computers. However, as it often happens, a simple login might take no less than 15 seconds.

I ran into this problem recently and had a investigation. As it turned out, there are multitude of factors that might affect the speed of the SSH login process. From the most obvious the to most inconspicuous, here are them:

• The sshd_config file.

This is the main configuration file that controls the behavior of the ssh daemon. In this file, you want to make sure the following features are disabled:

继续阅读Slow SSH Login

早上在法广首页看到新闻，吓一跳。

新闻链接戳这里：

赶紧点进去看，并把新闻发给了在菲律宾做生意的朋友。同时在其它媒体找相关信息。

继续阅读法广，seriously?

在wenxuecity上看到一片文章，原文发表于3月12日，转载如下：

继续阅读转载《读《思旧赋》》

上周翻书柜，又翻出这本《From mathematics to generic programming》，再到亚马逊上一搜，果然还没有中文版。我是Alexander Stepanov的粉丝，书一出来我就上美亚买了，就是打算翻译的。

买回来之后尝试翻译了几章，然后找了XX出版社，出版社看了告诉我说他们已经签了版权了，估计6个月中文版就出来了，于是只好撂下了。哪知道如今快两年过去了，中文版也还没影。

这几天我会跟作者联系，看看版权到底是个什么状态，同时会在这里放出以前翻译的草稿，欢迎批评指正。

If you’re looking for a method to write camera pose information into JPG files so that it can be read by Pix4D, as shown in the below screenshot:

Here is how to do it with exiftool:

• First, you need a configuration file for exiftool. In the configuration file, you need the following content:

%Image::ExifTool::UserDefined = (
    'Image::ExifTool::XMP::Main' => {
        Camera=> {
            SubDirectory => {
                TagTable => 'Image::ExifTool::UserDefined::Camera',
            },
        },
    },
);
%Image::ExifTool::UserDefined::Camera = (
    GROUPS => { 0 => 'XMP', 1 => 'XMP-Camera', 2 => 'Other' },
    NAMESPACE => { 'Camera' => 'http://ns.flyingfishtechs.com/Camera/1.0/' },
    WRITABLE => 'string',
    GPSXYAccuracy=> {},
    GPSZAccuracy => {},
    Pitch => {},
    Roll=>{},
    Yaw => {},
 );

• Then you can using exiftool to add the information to any JPG file.

exiftool.exe -config config.min.cfg -Pitch="1.02" -Roll="2.03" -Pitch="3.04" original.jpg

If the command outputs: 1 image files updated. Then you’re done. Now the JPG file has the camera pose information encoded in. If you have more than 3 such pictures (only because Pix4D needs at least 3 pictures to work), you can see that Pix4D can get the data from the pictures.

The final twist, Pix4D displays Omega, Phi and Kappa instead of Pitch, Roll and Yaw. Basically, Pitch, Roll and Yaw are angles relative to the horizontal plane – orthogonal to the gravity while Omega, Phi and Kappa are related to earth. That means, with a fixed set of Pitch, Roll and Yaw, if you change your GPS location, you’ll get a different set Omega, Phi and Kappa. Personally I don’t see why should Pix4D use earth as the frame of reference instead of horizontal plane. Maybe just to hide the raw information in the pictures. Anyway, know you know how.