An image to be recognized in the real-world environment during a world-tracking AR session.
在世界追蹤AR Session期間在真實世界環境中識別的圖像。
Overview
To accurately detect the position and orientation of a 2D image in the real world, ARKit requires preprocessed image data and knowledge of the image's real-world dimensions. The?ARReferenceImage?class encapsulates this information. To enable image detection in an AR session, pass a collection of reference images to your session configuration's?detectionImages?property.
Typically, you create reference images in your Xcode project's asset catalog:
In your asset catalog, use the Add (+) button to create an AR Resource Group.
Drag image files into the resource group to create AR Reference Image entries in the asset catalog.
For each reference image, use the Xcode inspector panel to provide the real-world size at which you want ARKit to recognize the image. (You can also provide a descriptive name, which appears as the?name?property at runtime and can be useful for debugging.)
概述
要準確檢測真實世界中2D圖像的位置和方向，ARKit需要預處理的圖像數據和圖像真實世界尺寸的知識。 ARReferenceImage類封裝了這些信息。 要在AR Session中啟用圖像檢測，請將參考圖像集合傳遞給Session配置的detectionImages屬性。
通常，您可以在Xcode項目的Asset目錄中創建參考圖像：
在您的Asset目錄中，使用添加（+）按鈕創建一個AR資源組。
將圖像文件拖放到資源組中以在資產目錄中創建AR參考圖像條目。
對于每個參考圖像，使用Xcode檢查器面板來提供您想讓ARKit識別圖像的實際大小。 （您也可以提供一個描述性名稱，它在運行時顯示為名稱屬性，可用于調試。）
? ? ? ? ? ? ? ? ? ? ? ? ? ? ?Loading Reference Images
+?referenceImagesInGroupNamed:bundle:
Loads all reference images in the specified AR Resource Group in your Xcode project's asset catalog.
加載Xcode項目Asset目錄中指定AR資源組中的所有參考圖像。
Parameters
name
The name of an AR Resource Group from your Xcode project's main asset catalog.?
來自Xcode項目主asset目錄的AR資源組的名稱。
bundle
The bundle from which to load asset catalog resources, or?nil?to use your app's main bundle.
要從中加載Asset目錄資源的包，或者不能使用您的應用的主包。
Return Value
A set of all unique reference images in the specified group.
返回值
指定組中所有唯一參考圖像的集合。
Discussion
To use the images for image detection in a world-tracking AR session, provide this set for your session configuration's?detectionImages?property.
討論
要在跟蹤世界的AR Session中使用圖像進行圖像檢測，請為會話配置的detectionImages屬性提供此設置。
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?Examining a Reference Image
name
A descriptive name for the image
圖像的描述性名稱
Discussion
For reference images loaded from an Xcode asset catalog, this property is the name assigned in the asset catalog. For programmatically created reference images, this value is?nil.?
ARKit does not make this string visible to the user, but it can be valuable for debugging.
討論
對于從Xcode資產目錄加載的參考圖像，此屬性是在Asset目錄中分配的名稱。 對于以編程方式創建的參考圖像，此值為零。
ARKit不會讓這個字符串對用戶可見，但它對調試很有價值。
physicalSize
The real-world dimensions, in meters, of the image.
圖像的實際尺寸（以米為單位）。
Discussion
To accurately recognize the position and orientation of an image in the AR environment, ARKit must know the image's physical size. You provide this information when creating an AR reference image in your Xcode project's asset catalog, or when programmatically creating a reference image with an?ARReferenceImage?initializer.
討論
為了準確識別AR環境中圖像的位置和方向，ARKit必須知道圖像的物理尺寸。 您在Xcode項目的Asset目錄中創建AR參考圖像時，或以編程方式創建具有ARReferenceImage初始值設定項的參考圖像時提供此信息。
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Creating Reference Images
-?initWithCGImage:orientation:physicalWidth:
Creates a new reference image from a Core Graphics image object.
從Core Graphics圖像對象創建新的參考圖像。
Parameters
image
A Core Graphics image object.
核心圖形圖像對象。
orientation
The intended display orientation for the image.?
圖像的預期顯示方向。
physicalWidth
The real-world width, in meters, of the image.
圖像的實際寬度（以米為單位）。
Discussion
To accurately recognize the position and orientation of an image in the AR environment, ARKit must know the image's physical size. When you call this initializer, ARKit uses the?physicalWidth?measurement and?orientation?you provide together with the aspect ratio of the image itself to calculate the physical height. Use the??physicalSize?property of the created?ARReferenceImage?object to retrieve these values.
Important
ARKit preprocesses reference images before using them for image detection. To provide reference images bundled with your app, create AR Reference Image assets in your Xcode asset catalog, and use the?referenceImageSetNamed:inBundle:?method to load them.
討論
為了準確識別AR環境中圖像的位置和方向，ARKit必須知道圖像的物理尺寸。 當您調用此初始值設定項時，ARKit使用您提供的physicalWidth測量值和方向以及圖像本身的高寬比來計算物理高度。 使用創建的ARReferenceImage對象的physicalSize屬性來檢索這些值。
重要
ARKit在使用它們進行圖像檢測之前預處理參考圖像。 要提供與您的應用捆綁在一起的參考圖像，請在您的Xcode資產目錄中創建AR參考圖像Asset，并使用referenceImageSetNamed：inBundle：方法加載它們。
-?initWithPixelBuffer:orientation:physicalWidth:
Creates a new reference image from a Core Video pixel buffer.
從核心視頻像素緩沖區創建新的參考圖像。
Parameters
image
A Core Graphics image object.
核心圖形圖像對象。
orientation
The intended display orientation for the image.?
圖像的預期顯示方向。
physicalWidth
The real-world width, in meters, of the image.
圖像的實際寬度（以米為單位）。
Discussion
To accurately recognize the position and orientation of an image in the AR environment, ARKit must know the image's physical size. When you call this initializer, ARKit uses the?physicalWidth?measurement and?orientation?you provide together with the aspect ratio of the image itself to calculate the physical height. Use the?physicalSize?property of the created?ARReferenceImage?object to retrieve these values.
Important
ARKit preprocesses reference images before using them for image detection. To provide reference images bundled with your app, create AR reference image assets in your Xcode asset catalog, and use the?referenceImagesInGroupNamed:bundle:?method to load them.
討論
為了準確識別AR環境中圖像的位置和方向，ARKit必須知道圖像的物理尺寸。 當您調用此初始值設定項時，ARKit使用您提供的physicalWidth測量值和方向以及圖像本身的高寬比來計算物理高度。 使用創建的ARReferenceImage對象的physicalSize屬性來檢索這些值。
重要
ARKit在使用它們進行圖像檢測之前預處理參考圖像。 要提供與您的應用捆綁在一起的參考圖像，請在您的Xcode資產目錄中創建AR參考圖像資產，然后使用referenceImagesInGroupNamed：bundle：方法加載它們。
Inherits From?NSObject
Conforms To?NSCopying
