#鸿蒙通关秘籍#如何在HarmonyOS NEXT中结合双路预览功能进行实时OCR识别？

在HarmonyOS NEXT中，实现双路预览结合OCR识别需遵循以下步骤：

1. 创建XComponentPage页面并添加相机预览视图。在XComponent中，调用getXComponentSurfaceId获取Surface ID，并使用此ID创建预览流。

   XComponent({
     id: 'LOXComponent',
     type: XComponentType.SURFACE,
     libraryname: 'SingleXComponent',
     controller: this.mXComponentController
   })
   .onLoad(() => {
     this.mXComponentController.setXComponentSurfaceSize({ surfaceWidth: 1920, surfaceHeight: 1080 });
     this.xComponentSurfaceId = this.mXComponentController.getXComponentSurfaceId();
   })
   .width("100%")
   .height(display.getDefaultDisplaySync().width * 9 / 16)
   

2. 创建双路预览函数，通过传递的Surface ID和ImageReceiver实例实现实时的多路相机图像预览。

   import camera from '@ohos.multimedia.camera';
   
   async createDualChannelPreview(cameraManager: camera.CameraManager, XComponentSurfaceId: string, receiver: image.ImageReceiver): Promise<void> {
     let camerasDevices = cameraManager.getSupportedCameras();
     let profiles = cameraManager.getSupportedOutputCapability(camerasDevices[0], camera.SceneMode.NORMAL_PHOTO);
     let previewProfiles = profiles.previewProfiles;
   
     let previewOutput = cameraManager.createPreviewOutput(previewProfiles[0], XComponentSurfaceId);
     let imageReceiverSurfaceId = await receiver.getReceivingSurfaceId();
     let previewOutput2 = cameraManager.createPreviewOutput(previewProfiles[0], imageReceiverSurfaceId);
   
     let cameraInput = cameraManager.createCameraInput(camerasDevices[0]);
     await cameraInput.open();
   
     let photoSession = cameraManager.createSession(camera.SceneMode.NORMAL_PHOTO) as camera.PhotoSession;
     photoSession.beginConfig();
     photoSession.addInput(cameraInput);
     photoSession.addOutput(previewOutput);
     photoSession.addOutput(previewOutput2);
     await photoSession.commitConfig();
     await photoSession.start();
   }
   

3. 使用ImageReceiver获取预览图像并进行OCR识别。

   onImageArrival(receiver: image.ImageReceiver): void {
     receiver.on('imageArrival', () => {
       receiver.readNextImage((err, nextImage) => {
         if (err || !nextImage) {
           console.error('readNextImage failed');
           return;
         }
         nextImage.getComponent(image.ComponentType.JPEG, async (err, imgComponent) => {
           if (err || !imgComponent) {
             console.error('getComponent failed');
             return;
           }
   
           if (imgComponent.byteBuffer as ArrayBuffer) {
             let imageSource = image.createImageSource(imgComponent.byteBuffer as ArrayBuffer);
             try {
               let imagePm = await imageSource.createPixelMap({ desiredSize: { width: 1920, height: 1080 } });
               ImageOCRUtil.recognizeText(imagePm, (res) => {
                 console.info(res);
               });
             } catch (err) {
               console.error(JSON.stringify(err));
             }
           }
           nextImage.release();
         });
       });
     });
   }