MATLAB - Matlab Camera Calibration Toolbox 的单位是什么 [英] MATLAB - What are the units of Matlab Camera Calibration Toolbox

问题描述

当显示校准的外在参数(包括相机位置和校准棋盘位置的 3D 模型)时，工具箱不包括轴的单位.假设它们以毫米为单位似乎是合乎逻辑的，但如果它们确实以毫米为单位，则显示的 z 值不可能正确.我假设正在进行一些转换，可能与光学坐标和单位有关，但我无法从文档中弄清楚.有没有人解决过这个问题?

When showing the extrinsic parameters of calibration (the 3D model including the camera position and the position of the calibration checkerboards), the toolbox does not include units for the axes. It seemed logical to assume that they are in mm, but the z values displayed can not possibly be correct if they are indeed in mm. I'm assuming that there is some transformation going on, perhaps having to do with optical coordinates and units, but I can't figure it out from the documentation. Has anyone solved this problem?

推荐答案

我对 matlabs 几乎一无所知(不完全正确，但我尽可能避免使用 matlab，这几乎总是可能的)跟踪实用程序，但这里有一些通用的信息.

I know next to nothing about matlabs (not entirely true but i avoid matlab wherever I can, and that would be almost always possible) tracking utilities but here's some general info.

传感器上的像素尺寸与屏幕上或模型空间中的像素尺寸无关.出于所有目的，相机产生的图片没有有意义的单位.跟踪过程不知道场景的规模.(透视投影负责).您可以通过获取 2 个跟踪点并测量这些点之间的距离来重新插入比例.这是求解器空间距离几乎是任意的.现在，如果您知道这些点之间的实际距离，您就可以获得一个转换系数.通过这样做:

Pixel dimension on the sensor has nothing to do with the size of the pixel on screen, or in model space. For all purposes a camera produces a picture that has no meaningful units. A tracking process is unaware of the scale of the scene. (the perspective projection takes care of that). You can re insert a scale by taking 2 tracked points and measuring the distance between those points. This is the solver spaces distance is pretty much arbitrary. Now if you know the real distance between these points you can get a conversion factor. By doing:

真实距离/求解器空间距离.

real distance / solver space distance.

现在真的有办法通过相机设置了解这个距离，因为相机无法区分不同比例的场景.因此，对于求解器来说，完美的 1:100 复制品与真实交易没有什么不同.因此，您必须与可以为每个测量会话单独测量的东西相关联.相机总是产生一些本质上相对的东西.

There's really now way to knowing this distance form the cameras settings as the camera is unable to differentiate between different scales of scenes. So a perfect 1:100 replica is no different for the solver than the real deal. So you must allays relate to something you can measure separately for each measuring session. The camera always produces something that's relative in nature.

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