摄影测量实习空中三角测量_摄影测量入门：Photoscan

叁歲伎倆 2022-12-07 12:13 434阅读 0赞

摄影测量实习空中三角测量

## 步骤1：准备使用Agisoft Photoscan进行摄影测量 **(** Step 1: Getting Ready to Use Agisoft Photoscan for Photogrammetry **)** ##

![978e643e34c953628f9a9dd5450e732a.png][]

[Agisoft Photoscan][] is an advanced photogrammetry application, which allows for much higher resolution images and larger scenes than [123D Catch][]. Available in Standard and Pro versions, the standard version is sufficient for interactive media tasks, while the Pro version is designed for authoring [GIS content][].

[Agisoft Photoscan][]是一种先进的摄影测量应用程序，与[123D Catch][]相比，它可提供分辨率更高的图像和更大的场景。 标准版提供标准版和专业版，足以满足交互式媒体任务的需要，而专业版则专为创作[GIS内容][GIS content]而设计。

While 123D Catch is a very useful tool for creating geometry, Photoscan offers a different workflow, which may be more useful to your project. This is most noticeable in three areas:Image resolution: 123D Catch converts all images to 3mpix for processing. This offers a good amount of detail in most cases, but may not be detailed enough depending on the scene.

尽管123D Catch是用于创建几何图形的非常有用的工具，但是Photoscan提供了不同的工作流程，这可能对您的项目更有用。 这在三个方面最为明显：图像分辨率：123D Catch将所有图像转换为3mpix进行处理。 在大多数情况下，这提供了大量细节，但根据场景可能不够详细。

Image count: If covering a large structure or complex object, more than 70 images may be required. Photoscan allows for large numbers of photos, which can be divided up by chunk to balance out the processing load.

图像计数：如果覆盖大型结构或复杂物体，则可能需要70幅以上的图像。 Photoscan允许使用大量照片，可以将这些照片按块划分以平衡处理负荷。

Geometric complexity: Photoscan is capable of producing models with millions of polygons. During the processing stage, the model is decimated (programmatic reduction of polygons) down to the number you define.

几何复杂度：Photoscan能够生成具有数百万个多边形的模型。 在处理阶段，将模型抽取(定义为多边形的方式减少)到您定义的数量。

Obviously these differences come with a cost. First, of course, is monetary. 123D Catch is a free service with premium options for those who require them. Second, the processing power required to calculate the output is all local, instead of cloud-based. To create the most complex models, you may need a multi-processor and/or GPU-augmented computer with up to 256GB of RAM. (Which isn’t possible to install in your average desktop computer… most are limited to 32GB).

显然，这些差异是有代价的。 首先，当然是金钱。 123D Catch是一项免费服务，为需要他们的人提供优质服务。 其次，计算输出所需的处理能力全部是本地的，而不是基于云的。 要创建最复杂的模型，您可能需要一台具有多达256GB RAM的多处理器和/或GPU增强型计算机。 (无法在普通台式计算机上安装……大多数限制为32GB)。

Photoscan is also far less intuitive, and requires more knowledge and manual tweaking of settings for optimal output.

Photoscan的直观性也要差得多，并且需要更多的知识和手动调整设置才能获得最佳输出。

For these reasons, you may find it useful to use both tools, depending on what your requirements are. Need something quick & simple, Catch may be a better choice. Want to reconstruct a cathedral with high detail? You may need to use Photoscan.

由于这些原因，根据您的要求，使用这两种工具可能会很有用。 需要快速，简单的方法，捕获可能是一个更好的选择。 想重建一个高细节的大教堂吗？ 您可能需要使用Photoscan。

Let’s get started by loading up Photoscan. (There is a trial available which won’t allow you to save your output if you want to give it a try.)

让我们开始加载Photoscan。 (有一个试用版，如果您想尝试一下，将无法保存您的输出。)

## 步骤2：加载和准备参考图像 **(** Step 2: Load and Prepare the Reference Images **)** ##

![f0eee95e40c3d4a2e91c7b5bded89079.png][]

Photoscan’s system, due to its precision, is far less forgiving of skies and other background elements than 123D Catch. While this means more set up time, it allows for significantly more detailed models.Load your photos into the scene by clicking Add Photos in the Workspace pane to the left.

由于具有高精度，Photoscan的系统比123D Catch对天空和其他背景元素的宽容度要低得多。 虽然这意味着需要更多的设置时间，但可以使用更详细的模型。单击左侧“工作区”窗格中的“添加照片”，将照片加载到场景中。

Use the Shift key to select all the photos, and click **Open**.

使用Shift键选择所有照片，然后点击**打开** 。

Expand the tree to the left, and you can get a list of Cameras, and indication that they are not yet aligned.

展开左侧的树，您可以获得摄像机的列表，并指示它们尚未对齐。

If your photos have any sky visible in particular, or other elements that are not relevant to your model, this is the stage where you remove those elements so that they are not used for processing. This will save you on processing time up front, and cleanup down the road.

如果您的照片中有特别可见的天空，或者与模型无关的其他元素，则在此阶段删除这些元素，以便不将其用于处理。 这将节省您的前期处理时间，并在以后进行清理。

Be sure to mask areas where something is in one frame but not another. (For example, a bird flying across the frame in a single shot.) Masking out a detail in a single frame has minimal impact if you have multiple overlapping frames.

确保遮盖一帧中有东西的区域，而不是另一帧中的区域。 (例如，一只鸟在单张照片中飞过整个帧。)如果有多个重叠的帧，则在单个帧中掩盖细节的影响最小。

Double-click on one of the images, and use the selection tools to select an area, then click “Add Selection”, or Ctrl-Shift-A. Go through all of your images to make sure you have removed unwanted data.

双击其中一张图像，然后使用选择工具选择一个区域，然后单击“添加选择”或Ctrl-Shift-A。 浏览所有图像，确保已删除不需要的数据。

## 步骤3：对准相机 **(** Step 3: Align the Cameras **)** ##

![cc18a74449ca40f46e4aa9f9043ec280.png][]

Once you have a clean set of camera data, save your scene, close the photo tabs you have opened, and return to the Perspective view.Click Workflow->Align photos. If you want quick results, choose low precision to start with. Disable pair preselection, and make sure the Constrain features by mask is checked if you masked your photos.Click OK.

有了一组干净的相机数据后，保存场景，关闭打开的照片选项卡，然后返回到“透视”视图。单击“工作流程”->“对齐照片”。 如果要快速获得结果，请选择低精度。 如果您屏蔽了照片，请禁用配对预选择，并确保已选中“按屏蔽限制功能”。单击“确定”。

What results is a “point cloud”, which is a series of reference points that will form the basis of your future geometry. Examine the scene, and make sure all the cameras seem to be pointing where they should be. If not, adjust the masking or disable that camera for the time being, and re-align the cameras. Repeat, until the point cloud looks correct.

结果就是“点云”，它是一系列参考点，这些参考点将构成您将来的几何图形的基础。 检查场景，并确保所有摄像机似乎都指向了应该放置的位置。 如果没有，请暂时调整遮罩或禁用该相机，然后重新对齐相机。 重复，直到点云看起来正确为止。

## 步骤4：预览几何 **(** Step 4: Preview the Geometry **)** ##

![42aaa7147a040259908c7f539de5ae0a.png][]

Use the Resize Region and Rotate Region tools to adjust the bounding box for the geometry. Any points outside of this box will be ignored for calculation.

使用“调整区域大小”和“旋转区域”工具调整几何的边界框。 此框外的任何点都将被忽略以进行计算。

Click Workflow->Build Geometry.

单击工作流程->构建几何。

Choose Arbitrary, Smooth, Lowest, 10000 faces, and click OK.This should give you a quick idea of what your final output will look like.

选择任意，平滑，最低，10000个面，然后单击确定，这将使您快速了解最终输出的外观。

## 步骤5：建立最终几何 **(** Step 5: Build Final Geometry **)** ##

![1e454d7521766a17695b955914ad325c.png][]

If everything looks ok, set the quality to Medium, and 100,000 faces, and recalculate. You will notice a significant increase in processing time, but the resulting detail is well worth the time.

如果一切正常，请将画质设置为“中”，并设置100,000张面，然后重新计算。 您会注意到处理时间显着增加，但是由此产生的细节是值得的。

If you have sections of geometry that you don’t want on the final model, use the selection tools to highlight and remove them.

如果最终模型上不需要几何部分，请使用选择工具突出显示并删除它们。

## 步骤6：构建纹理 **(** Step 6: Build the Texture **)** ##

![7b0e6768f4ae1e8c7eb97a44ee0818dc.png][]

Once you are satisfied with your geometry, it is time to add the final touch.

对几何体感到满意之后，就该添加最后的修饰了。

Click Workflow->Build Texture.

单击工作流程->构建纹理。

Choose Generic, Average, Fill Holes, 2048x2048, and Standard (24-bit). Click **OK.**

选择“通用”，“平均”，“填充Kong”，“ 2048x2048”和“标准”(24位)。 单击**确定。**

When the process completes, the texture will be applied to your model, and ready for use.

该过程完成后，纹理将应用于模型，并可供使用。

> 翻译自: [https://www.thoughtco.com/getting-started-with-photogrammetry-photoscan-1393988][https_www.thoughtco.com_getting-started-with-photogrammetry-photoscan-1393988]

摄影测量实习空中三角测量

[978e643e34c953628f9a9dd5450e732a.png]: /images/20221123/d6140c7e11e74f5b83790fdfe84d890d.png
[Agisoft Photoscan]: http://www.agisoft.ru/
[123D Catch]: http://www.123dapp.com/catch
[GIS content]: https://www.thoughtco.com/what-is-acronym-1689058
[f0eee95e40c3d4a2e91c7b5bded89079.png]: /images/20221123/a442a9d488df4fc397659812b0a9ad1b.png
[cc18a74449ca40f46e4aa9f9043ec280.png]: /images/20221123/63537eb0e73441e1bef38aa1ef806701.png
[42aaa7147a040259908c7f539de5ae0a.png]: /images/20221123/e3125e50dca7480b903c11d1cb912cfc.png
[1e454d7521766a17695b955914ad325c.png]: /images/20221123/d76cb529288b438993ca1618d3a5137c.png
[7b0e6768f4ae1e8c7eb97a44ee0818dc.png]: /images/20221123/7fd430e39a5647f49c6bfe65c9338d89.png
[https_www.thoughtco.com_getting-started-with-photogrammetry-photoscan-1393988]: https://www.thoughtco.com/getting-started-with-photogrammetry-photoscan-1393988