瞭解如何在自己的應用程式中使用擴增圖片。
必要條件
請務必瞭解基本 AR 概念 以及如何在繼續操作前設定 ARCore 工作階段。
建立映像檔資料庫
每個圖片資料庫最多可儲存 1,000 張圖片的資訊。
您可以透過兩種方式建立
AugmentedImageDatabase
:
- 載入已儲存的圖片資料庫。並視需要新增更多參考圖片。
- 建立新的空白資料庫。然後逐一新增參考圖片。
載入已儲存的圖片資料庫
使用 AugmentedImageDatabase.deserialize()
載入現有的映像檔資料庫:
Java
AugmentedImageDatabase imageDatabase; try (InputStream inputStream = this.getAssets().open("example.imgdb")) { imageDatabase = AugmentedImageDatabase.deserialize(session, inputStream); } catch (IOException e) { // The Augmented Image database could not be deserialized; handle this error appropriately. }
Kotlin
val imageDatabase = this.assets.open("example.imgdb").use { AugmentedImageDatabase.deserialize(session, it) }
您可以使用 arcoreimg
建立映像檔資料庫
或在開發期間呼叫
AugmentedImageDatabase.serialize()
。
您就會在記憶體中載入該資料庫
建立新的空白資料庫
如要在執行階段建立空白圖片資料庫,請使用 AugmentedImageDatabase
建構函式:
Java
AugmentedImageDatabase imageDatabase = new AugmentedImageDatabase(session);
Kotlin
val imageDatabase = AugmentedImageDatabase(session)
將圖片加入現有資料庫
呼叫
AugmentedImageDatabase.addImage()
敬上
為每個圖片指定選用 widthInMeters
Java
Bitmap bitmap; try (InputStream bitmapString = getAssets().open("dog.jpg")) { bitmap = BitmapFactory.decodeStream(bitmapString); } catch (IOException e) { // The bitmap could not be found in assets; handle this error appropriately. throw new AssertionError("The bitmap could not be found in assets.", e); } // If the physical size of the image is not known, use addImage(String, Bitmap) instead, at the // expense of an increased image detection time. float imageWidthInMeters = 0.10f; // 10 cm int dogIndex = imageDatabase.addImage("dog", bitmap, imageWidthInMeters);
Kotlin
val bitmap = assets.open("dog.jpg").use { BitmapFactory.decodeStream(it) } // If the physical size of the image is not known, use addImage(String, Bitmap) instead, at the // expense of an increased image detection time. val imageWidthInMeters = 0.10f // 10 cm val dogIndex = imageDatabase.addImage("dog", bitmap, imageWidthInMeters)
傳回的索引之後,就能識別出哪個參考圖像 。
啟用圖片追蹤功能
設定工作階段,以設定 ARCore 工作階段開始追蹤圖片 設定為使用所需映像檔資料庫的叢集:
Java
Config config = new Config(session); config.setAugmentedImageDatabase(imageDatabase); session.configure(config);
Kotlin
val config = Config(session) config.augmentedImageDatabase = imageDatabase session.configure(config)
在工作階段期間,ARCore 會比對 比對圖片資料庫中的圖片
如要取得相符的圖片,請在影格更新迴圈中輪詢最新的 AugmentedImage
。
Java
Collection<AugmentedImage> updatedAugmentedImages = frame.getUpdatedTrackables(AugmentedImage.class); for (AugmentedImage img : updatedAugmentedImages) { if (img.getTrackingState() == TrackingState.TRACKING) { // Use getTrackingMethod() to determine whether the image is currently // being tracked by the camera. switch (img.getTrackingMethod()) { case LAST_KNOWN_POSE: // The planar target is currently being tracked based on its last // known pose. break; case FULL_TRACKING: // The planar target is being tracked using the current camera image. break; case NOT_TRACKING: // The planar target isn't been tracked. break; } // You can also check which image this is based on img.getName(). if (img.getIndex() == dogIndex) { // TODO: Render a 3D version of a dog in front of img.getCenterPose(). } else if (img.getIndex() == catIndex) { // TODO: Render a 3D version of a cat in front of img.getCenterPose(). } } }
Kotlin
val updatedAugmentedImages = frame.getUpdatedTrackables(AugmentedImage::class.java) for (img in updatedAugmentedImages) { if (img.trackingState == TrackingState.TRACKING) { // Use getTrackingMethod() to determine whether the image is currently // being tracked by the camera. when (img.trackingMethod) { AugmentedImage.TrackingMethod.LAST_KNOWN_POSE -> { // The planar target is currently being tracked based on its last known pose. } AugmentedImage.TrackingMethod.FULL_TRACKING -> { // The planar target is being tracked using the current camera image. } AugmentedImage.TrackingMethod.NOT_TRACKING -> { // The planar target isn't been tracked. } } // You can also check which image this is based on AugmentedImage.getName(). when (img.index) { dogIndex -> TODO("Render a 3D version of a dog at img.getCenterPose()") catIndex -> TODO("Render a 3D version of a cat at img.getCenterPose()") } } }
支援不同用途
當 ARCore 偵測到擴增圖片時,就會為該圖片建立 Trackable
擴增圖片和組合 TrackingState
到TRACKING
和TrackingMethod
至 FULL_TRACKING
。當追蹤的圖像從相機畫面中移出時,ARCore
變更 TrackingMethod
至 LAST_KNOWN_POSE
,同時繼續提供
該圖片
您的應用程式應根據預期用途,以不同方式使用這些列舉 確認是否屬於此情況
固定圖片:大多數涉及固定圖片的用途 只要使用
TrackingState
就能判斷 是否會偵測到圖片,以及圖片的位置是否已知。 您可以忽略TrackingMethod
。移動圖片。如果您的應用程式需要追蹤移動的圖片,請同時使用
TrackingState
和TrackingMethod
用來判斷圖片是否已 以及其位置是否已知。
用途 | 固定圖片 | 正在移動圖片 |
---|---|---|
範例 | 掛在牆上的海報 | 公車旁的廣告 |
姿勢可以: 視為有效的 |
TrackingState == TRACKING |
TrackingState == TRACKING
和 TrackingMethod == FULL_TRACKING
|
另請參閱
擴增映像檔範例專案 。