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ImageAnalysis

public final class ImageAnalysis
extends UseCase

java.lang.Object
   ↳ androidx.camera.core.UseCase
     ↳ androidx.camera.core.ImageAnalysis

A use case providing CPU accessible images for an app to perform image analysis on.

ImageAnalysis acquires images from the camera via an ImageReader. Each image is provided to an ImageAnalysis.Analyzer function which can be implemented by application code, where it can access image data for application analysis via an ImageProxy.

After the analyzer function returns, the ImageProxy will be closed and the corresponding Image is released back to the ImageReader.

Summary

Nested classes

interface ImageAnalysis.Analyzer

Interface for analyzing images. 

enum ImageAnalysis.ImageReaderMode

The different ways that the image sent to the analyzer is acquired from the underlying ImageReader. 

Public constructors

ImageAnalysis(ImageAnalysisConfig config)

Creates a new image analysis use case from the given configuration.

Public methods

ImageAnalysis.Analyzer getAnalyzer()

Retrieves a previously set analyzer.

void removeAnalyzer()

Removes a previously set analyzer.

void setAnalyzer(ImageAnalysis.Analyzer analyzer)

Sets an analyzer to receive and analyze images.

void setTargetRotation(int rotation)

Sets the target rotation.

String toString()

Inherited methods

Public constructors

ImageAnalysis

public ImageAnalysis (ImageAnalysisConfig config)

Creates a new image analysis use case from the given configuration.

Parameters
config ImageAnalysisConfig: for this use case instance

Public methods

getAnalyzer

public ImageAnalysis.Analyzer getAnalyzer ()

Retrieves a previously set analyzer.

Returns
ImageAnalysis.Analyzer The last set analyzer or null if no analyzer is set.

removeAnalyzer

public void removeAnalyzer ()

Removes a previously set analyzer.

This is equivalent to calling setAnalyzer(null). This will stop data from streaming to the ImageAnalysis.

setAnalyzer

public void setAnalyzer (ImageAnalysis.Analyzer analyzer)

Sets an analyzer to receive and analyze images.

Setting an analyzer will signal to the camera that it should begin sending data. The stream of data can be stopped by setting the analyzer to null or by calling removeAnalyzer().

Applications can process or copy the image by implementing the ImageAnalysis.Analyzer. If frames should be skipped (no analysis), the analyzer function should return, instead of disconnecting the analyzer function completely.

Setting an analyzer function replaces any previous analyzer. Only one analyzer can be set at any time.

Parameters
analyzer ImageAnalysis.Analyzer: of the images or null to stop data streaming to ImageAnalysis.

setTargetRotation

public void setTargetRotation (int rotation)

Sets the target rotation.

This informs the use case so it can adjust the rotation value sent to ImageAnalysis.Analyzer.analyze(ImageProxy, int).

In most cases this should be set to the current rotation returned by Display.getRotation(). In that case, the rotation parameter sent to the analyzer will be the rotation, which if applied to the output image, will make the image match the display orientation.

While rotation can also be set via ImageAnalysisConfig.Builder.setTargetRotation(int), using setTargetRotation(int) allows the target rotation to be set dynamically. This can be useful if an app locks itself to portrait, and uses the orientation sensor to set rotation, to process landscape images when the device is rotated by examining the rotation received by the Analyzer function.

If no target rotation is set by the application, it is set to the value of Display.getRotation() of the default display at the time the use case is created.

Parameters
rotation int: Target rotation of the output image, expressed as one of Surface.ROTATION_0, Surface.ROTATION_90, Surface.ROTATION_180, or Surface.ROTATION_270.

toString

public String toString ()

Returns
String