ImageAnalysis.Builder
class ImageAnalysis.Builder : ExtendableBuilder
Builder for a ImageAnalysis.
Summary
Public constructors |
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Builder()Creates a new Builder object. |
Public functions |
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ImageAnalysis |
build()Builds an |
ImageAnalysis.Builder |
setBackgroundExecutor(executor: Executor)Sets the default executor that will be used for background tasks. |
ImageAnalysis.Builder |
setBackpressureStrategy(strategy: Int)Sets the backpressure strategy to apply to the image producer to deal with scenarios where images may be produced faster than they can be analyzed. |
ImageAnalysis.Builder |
setImageQueueDepth(depth: Int)Sets the number of images available to the camera pipeline for |
ImageAnalysis.Builder |
setOutputImageFormat(outputImageFormat: Int)Sets output image format. |
ImageAnalysis.Builder |
@RequiresApi(value = 23)Enable or disable output image rotation. |
ImageAnalysis.Builder |
setResolutionSelector(resolutionSelector: ResolutionSelector)Sets the resolution selector to select the preferred supported resolution. |
ImageAnalysis.Builder |
This function is deprecated. use |
ImageAnalysis.Builder |
setTargetName(targetName: String)Sets the name of the target object being configured, used only for debug logging. |
ImageAnalysis.Builder |
This function is deprecated. use |
ImageAnalysis.Builder |
setTargetRotation(rotation: Int)Sets the rotation of the intended target for images from this configuration. |
Public functions
build
fun build(): ImageAnalysis
Builds an ImageAnalysis from the current state.
| Returns | |
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ImageAnalysis |
A |
| Throws | |
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java.lang.IllegalArgumentException |
if attempting to set both target aspect ratio and target resolution. |
setBackgroundExecutor
fun setBackgroundExecutor(executor: Executor): ImageAnalysis.Builder
Sets the default executor that will be used for background tasks.
If not set, the background executor will default to an automatically generated Executor.
| Parameters | |
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executor: Executor |
The executor which will be used for background tasks. |
| Returns | |
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ImageAnalysis.Builder |
the current Builder. |
setBackpressureStrategy
fun setBackpressureStrategy(strategy: Int): ImageAnalysis.Builder
Sets the backpressure strategy to apply to the image producer to deal with scenarios where images may be produced faster than they can be analyzed.
The available values are STRATEGY_BLOCK_PRODUCER and STRATEGY_KEEP_ONLY_LATEST.
If not set, the backpressure strategy will default to STRATEGY_KEEP_ONLY_LATEST.
| Parameters | |
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strategy: Int |
The strategy to use. |
| Returns | |
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ImageAnalysis.Builder |
The current Builder. |
setImageQueueDepth
fun setImageQueueDepth(depth: Int): ImageAnalysis.Builder
Sets the number of images available to the camera pipeline for STRATEGY_BLOCK_PRODUCER mode.
The image queue depth is the number of images available to the camera to fill with data. This includes the image currently being analyzed by analyze. Increasing the image queue depth may make camera operation smoother, depending on the backpressure strategy, at the cost of increased memory usage.
When the backpressure strategy is set to STRATEGY_BLOCK_PRODUCER, increasing the image queue depth may make the camera pipeline run smoother on systems under high load. However, the time spent analyzing an image should still be kept under a single frame period for the current frame rate, on average, to avoid stalling the camera pipeline.
The value only applies to STRATEGY_BLOCK_PRODUCER mode. For STRATEGY_KEEP_ONLY_LATEST the value is ignored.
If not set, and this option is used by the selected backpressure strategy, the default will be a queue depth of 6 images.
| Parameters | |
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depth: Int |
The total number of images available to the camera. |
| Returns | |
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ImageAnalysis.Builder |
The current Builder. |
setOutputImageFormat
fun setOutputImageFormat(outputImageFormat: Int): ImageAnalysis.Builder
Sets output image format.
The supported output image format is OUTPUT_IMAGE_FORMAT_YUV_420_888 and OUTPUT_IMAGE_FORMAT_RGBA_8888.
If not set, OUTPUT_IMAGE_FORMAT_YUV_420_888 will be used. Requesting OUTPUT_IMAGE_FORMAT_RGBA_8888 will have extra overhead because format conversion takes time.
| Parameters | |
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outputImageFormat: Int |
The output image format. |
| Returns | |
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ImageAnalysis.Builder |
The current Builder. |
setOutputImageRotationEnabled
@RequiresApi(value = 23)
fun setOutputImageRotationEnabled(outputImageRotationEnabled: Boolean): ImageAnalysis.Builder
Enable or disable output image rotation.
On API 22 and below, this API has no effect. User needs to handle the image rotation based on the getRotationDegrees.
setTargetRotation is to adjust the rotation degree information returned by getRotationDegrees based on sensor rotation and user still needs to rotate the output image to achieve the target rotation. Once this is enabled, user doesn't need to handle the rotation, the output image will be a rotated ImageProxy and getRotationDegrees will return 0.
Turning this on will add more processing overhead to every image analysis frame. The average processing time is about 10-15ms for 640x480 image on a mid-range device. By default, the rotation is disabled.
| Parameters | |
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outputImageRotationEnabled: Boolean |
flag to enable or disable. |
| Returns | |
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ImageAnalysis.Builder |
The current Builder. |
setResolutionSelector
fun setResolutionSelector(resolutionSelector: ResolutionSelector): ImageAnalysis.Builder
Sets the resolution selector to select the preferred supported resolution.
ImageAnalysis has a default ResolutionStrategy with bound size as 640x480 and fallback rule of FALLBACK_RULE_CLOSEST_HIGHER_THEN_LOWER. Applications can override this default strategy with a different resolution strategy.
When using the camera-camera2 CameraX implementation, which resolution is finally selected depends on the camera device's hardware level, capabilities and the bound use cases combination. The device hardware level and capabilities information can be retrieved via the interop class getCameraCharacteristic with INFO_SUPPORTED_HARDWARE_LEVEL and REQUEST_AVAILABLE_CAPABILITIES.
A LIMITED-level above device can support a RECORD size resolution for ImageAnalysis when it is bound together with Preview and ImageCapture. The trade-off is the selected resolution for the ImageCapture is also restricted by the RECORD size. To successfully select a RECORD size resolution for ImageAnalysis, a ResolutionStrategy of selecting RECORD size resolution should be set on both ImageCapture and ImageAnalysis. This indicates that the application clearly understand the trade-off and prefer the ImageAnalysis to have a larger resolution rather than the ImageCapture to have a MAXIMUM
size resolution. For the definitions of RECORD, MAXIMUM sizes and more details see the Regular capture section in android.hardware.camera2.CameraDevice's. The RECORD size refers to the camera device's maximum supported recording resolution, as determined by CamcorderProfile. The MAXIMUM size refers to the camera device's maximum output resolution for that format or target from getOutputSizes.
The existing setTargetResolution and setTargetAspectRatio APIs are deprecated and are not compatible with setResolutionSelector. Calling either of these APIs together with setResolutionSelector will result in an IllegalArgumentException being thrown when you attempt to build the ImageAnalysis instance.
| Returns | |
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ImageAnalysis.Builder |
The current Builder. |
funsetTargetAspectRatio(aspectRatio: Int): ImageAnalysis.Builder
Sets the aspect ratio of the intended target for images from this configuration.
The aspect ratio is the ratio of width to height in the sensor orientation.
It is not allowed to set both target aspect ratio and target resolution on the same use case. Attempting so will throw an IllegalArgumentException when building the Config.
The target aspect ratio is used as a hint when determining the resulting output aspect ratio which may differ from the request, possibly due to device constraints. Application code should check the resulting output's resolution and the resulting aspect ratio may not be exactly as requested.
If not set, or RATIO_DEFAULT is supplied, resolutions with aspect ratio 4:3 will be considered in higher priority.
| Parameters | |
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aspectRatio: Int |
The desired ImageAnalysis |
| Returns | |
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ImageAnalysis.Builder |
The current Builder. |
setTargetName
fun setTargetName(targetName: String): ImageAnalysis.Builder
Sets the name of the target object being configured, used only for debug logging.
The name should be a value that can uniquely identify an instance of the object being configured.
If not set, the target name will default to a unique name automatically generated with the class canonical name and random UUID.
| Parameters | |
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targetName: String |
A unique string identifier for the instance of the class being configured. |
| Returns | |
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ImageAnalysis.Builder |
the current Builder. |
funsetTargetResolution(resolution: Size): ImageAnalysis.Builder
Sets the resolution of the intended target from this configuration.
The target resolution attempts to establish a minimum bound for the image resolution. The actual image resolution will be the closest available resolution in size that is not smaller than the target resolution, as determined by the Camera implementation. However, if no resolution exists that is equal to or larger than the target resolution, the nearest available resolution smaller than the target resolution will be chosen. Resolutions with the same aspect ratio of the provided Size will be considered in higher priority before resolutions of different aspect ratios.
It is not allowed to set both target aspect ratio and target resolution on the same use case. Attempting so will throw an IllegalArgumentException when building the Config.
The resolution Size should be expressed in the coordinate frame after rotating the supported sizes by the target rotation. For example, a device with portrait natural orientation in natural target rotation requesting a portrait image may specify 480x640, and the same device, rotated 90 degrees and targeting landscape orientation may specify 640x480.
If not set, resolution of 640x480 will be selected to use in priority.
When using the camera-camera2 CameraX implementation, which resolution will be finally selected will depend on the camera device's hardware level and the bound use cases combination. The device hardware level information can be retrieved by INFO_SUPPORTED_HARDWARE_LEVEL from the interop class getCameraCharacteristic. A LIMITED-level above device can support a RECORD size resolution for ImageAnalysis when it is bound together with Preview and ImageCapture. The trade-off is the selected resolution for the ImageCapture will also be restricted by the RECORD size. To successfully select a RECORD size resolution for ImageAnalysis, a RECORD size target resolution should be set on both ImageCapture and ImageAnalysis. This indicates that the application clearly understand the trade-off and prefer the ImageAnalysis to have a larger resolution rather than the ImageCapture to have a MAXIMUM size resolution. For the definitions of RECORD, MAXIMUM sizes and more details see the Regular capture section in android.hardware.camera2.CameraDevice's. The RECORD size refers to the camera device's maximum supported recording resolution, as determined by CamcorderProfile. The MAXIMUM size refers to the camera device's maximum output resolution for that format or target from getOutputSizes.
| Parameters | |
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resolution: Size |
The target resolution to choose from supported output sizes list. |
| Returns | |
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ImageAnalysis.Builder |
The current Builder. |
setTargetRotation
fun setTargetRotation(rotation: Int): ImageAnalysis.Builder
Sets the rotation of the intended target for images from this configuration.
This adjust the getRotationDegrees of the ImageProxy passed to analyze. The rotation value of ImageInfo will be the rotation, which if applied to the output image, will make the image match target rotation specified here.
This is one of four valid values: ROTATION_0, ROTATION_90, ROTATION_180, ROTATION_270. Rotation values are relative to the "natural" rotation, ROTATION_0.
In general, it is best to additionally set the target rotation dynamically on the use case. See setTargetRotation for additional documentation.
If not set, the target rotation will default to the value of getRotation of the default display at the time the use case is created. The use case is fully created once it has been attached to a camera.
| Parameters | |
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rotation: Int |
The rotation of the intended target. |
| Returns | |
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ImageAnalysis.Builder |
The current Builder. |