Die Verwaltung und Nutzung der Kamera- und Systemkonfiguration wurde ebenfalls aktualisiert in Extended View System (EVS) 1.1. Da EVS 1.0 keine Methoden zum Abfragen Kamerageräteinformationen und Systemkonfiguration müssen, muss der App-Entwickler diese Informationen selbst zu erhalten. Beispiel: Der Kunde muss über eine Kamera verfügen. Kalibrierungsdaten, falls einige Apps für maschinelles Sehen implementiert sind.
Um diesen Umstand zu beheben, erweitert EVS 1.1 einen Kameragerätedeskriptor um Kamerametadaten festgelegt und bietet mehrere Methoden, mit denen Clients auf die Kamera zugreifen können. Geräte- und Systemkonfigurationsinformationen.
import android.frameworks.cameraservice.device@2.0::CameraMetadata; import android.frameworks.cameraservice.common@2.0::CameraMetadataType; /** * Structure describing the basic properties of an EVS camera, extended * from its v1.0 declaration. * * The HAL is responsible for filling out this structure for each * EVS camera in the system. */ struct CameraDesc { @1.0::CameraDesc v1; /** * Store camera metadata such as lens characteristics. */ CameraMetadata metadata; };
CameraDesc ist auf Metadaten für Kamerageräte erweitert und das
Typ wird aus android.frameworks.cameraservice.device@2.0 importiert.
Bei diesem Design können Anbieter camera_metadata_t verwenden
und die in ANDROID_SCALER_AVAILABLE_STREAM_CONFIGURATIONS definierten APIs zu nutzen. Der EVS-Fahrer kann
um zu ermitteln, welche Streamkonfigurationen vom jeweiligen Kameramodul unterstützt werden.
Außerdem dürfen Anbieter ihre eigenen Metadatentypen nicht verwenden, um andere Informationen bereitzustellen, die nicht in Android definiert sind, wie unter ANDROID_SCALER_AVAILABLE_STREAM_CONFIGURATIONS erläutert. Der EVS-Fahrer kann
um zu ermitteln, welche Streamkonfigurationen vom jeweiligen Kameramodul unterstützt werden.
Kamera mit der gewünschten Streamkonfiguration öffnen
import android.hardware.camera.device@3.2::Stream; /** * Get the IEvsCamera associated with a cameraId from a CameraDesc * * Given a camera's unique cameraId from CameraDesc, returns the * IEvsCamera interface associated with the specified camera. When * done using the camera, the caller may release it by calling closeCamera(). * * @param cameraId A unique identifier of the camera. * @param streamCfg A stream configuration the client wants to use. * @return evsCamera EvsCamera object associated with a given cameraId. */ openCamera_1_1(string cameraId, Stream streamCfg) generates (IEvsCamera evsCamera);
Eines der von Android definierten Metadatenfelder ist ANDROID_SCALER_AVAILABLE_STREAM_CONFIGURATIONS. Der EVS-Fahrer kann
um zu ermitteln, welche
Streamkonfigurationen unterstützt werden,
pro Kameramodul. Die unten bereitgestellte Referenzimplementierung listet beispielsweise die
Informationen zu den einzelnen unterstützten Streamkonfigurationen:
- Stream-ID
- Breite
- Größe
- Richtung (Eingabe oder Ausgabe)
- Framerate
Mehrere Clients auf einer einzelnen Kamera-Hardwareinstanz
Wenn ein Client das Öffnen eines bereits aktiven Kamerageräts anfordert, wird der EVS eine angeforderte Streamkonfiguration mit der aktiven Konfiguration verglichen. Bei unterschiedlichen Werten gibt der EVS-Manager ein Null-IEvsCamera-Objekt zurück. Der Kunde MÜSSEN diesen möglichen Fehler ordnungsgemäß verarbeiten.
Referenzkonfigurationsdatei
Die in EVS 1.1 enthaltene Referenzkonfigurationsdatei ist in XML geschrieben und Anbieter können die enthaltene DTD-Datei (siehe unten) verwenden, um eine (geänderte) Beispielkonfigurationsdatei erstellen oder eine eigene Datei verwenden, wenn sie dasselbe Format verwenden möchten. Die DTD-Datei enthält außerdem detaillierte Beschreibungen für die einzelnen Elemente und Attribute.
<?xml version='1.0' encoding='utf-8'?> <!-- Copyright (C) 2019 The Android Open Source Project Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. -->
<!-- Author : changyeon@google.com Version: 1.0 --> <!ELEMENT configuration (system,camera,display)> <!-- System Configuration that contains below informations: - The dimension of the vehicle. - Number of cameras available to EVS. - List of predefined use cases. --> <!ELEMENT system (dimension,num_cameras,supported_use_case*)> <!-- The x, y, and z dimension of the vehicle in the unit of centimeters. Axes are defined at https://source.android.com/docs/core/interaction/sensors/sensor-types#auto_axes --> <!ELEMENT dimension EMPTY> <!ATTLIST dimension x CDATA '0' y CDATA '0' z CDATA '0' > <!-- The number of cameras that are available to EVS on the vehicle. This must be equal to the number of camera elements of the device element. --> <!ELEMENT num_cameras EMPTY> <!ATTLIST num_cameras value CDATA #REQUIRED > <!-- List of predefined use cases --> <!ELEMENT supported_use_case (use_case)*> <!-- Predefined configurations for each of listed use cases. @attr id : Unique string identifier of this use case. @attr camera : ID of either a single camera device or a camera group. @attr stream_id: Preferred stream configuration of camera device/group that is set by camera attribute. --> <!ELEMENT use_case EMPTY> <!ATTLIST use_case id CDATA #REQUIRED camera CDATA #REQUIRED stream_id CDATA #REQUIRED > <!-- Device descriptions --> <!ELEMENT camera (group|device)*> <!-- Camera group descriptor @attr group_id : Unique logical camera group identifier. Camera device use this to be a member of the group. @attr device_id : Comma-separated list of unique camera identifiers of member camera devices. @attr synchronized: Boolean field that tells whether or not this camera is synchronized with other cameras in the same group. This is ineffective if there is a single camera in the group or a group is invalid. --> <!ELEMENT group (caps)> <!ATTLIST group group_id CDATA #REQUIRED device_id CDATA #REQUIRED synchronized CDATA #REQUIRED > <!-- Please note that a camera may have stream configurations. If it has, all stream configurations must be supported by each camera device in the group. --> <!-- Camera device descriptor @attr id : Unique camera identifier. @attr position : Must be one of front, rear, left, or right. --> <!ELEMENT device (caps,characteristics*)> <!ATTLIST device id CDATA #REQUIRED position CDATA #REQUIRED > <!-- Camera metadata that contains: - A list of supported controls. - A list of supported stream configurations. --> <!ELEMENT caps (supported_controls|stream)*> <!-- A list of supported controls. This must be a subset of android.hardware.automotive.evs@1.1::CameraParam. --> <!ELEMENT supported_controls EMPTY> <!ATTLIST supported_controls value CDATA #REQUIRED > <!-- A list of supported output sizes. --> <!ELEMENT stream EMPTY> <!ATTLIST stream id CDATA #REQUIRED width CDATA #REQUIRED height CDATA #REQUIRED format CDATA #REQUIRED > <!-- Camera module characteristics including its optics and imaging sensor. --> <!ELEMENT characteristics (parameter)*> <!ELEMENT parameter EMPTY> <!-- A name of camera characteristic. This must be a subset of android.hardware.automotive.evs@1.1::CameraCharacteristics. --> <!ATTLIST parameter name CDATA #REQUIRED type CDATA #REQUIRED size CDATA #REQUIRED value CDATA #REQUIRED > <!-- Available display devices --> <!ELEMENT display (display_device)*> <!-- Display device descriptor @attr id : Unique display identifier. @attr position: Display mount location. --> <!ELEMENT display_device (supported_formats)*> <!ATTLIST display_device id CDATA #REQUIRED position CDATA #REQUIRED > <!-- A list of supported input data formats. @attr value: A comma separated list of input data formats --> <!ELEMENT supported_formats EMPTY> <!ATTLIST supported_formats value CDATA #REQUIRED >
Im Folgenden finden Sie ein Beispiel für eine Konfigurationsdatei (das Beispiel enthält numerische Dummy-Daten).
<?xml version='1.0' encoding='utf-8'?> <!-- Copyright (C) 2019 The Android Open Source Project Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. --> <!-- Extended View System Example Configuration Android Automotive axes are used to define coordinates. See https://source.android.com/docs/core/interaction/sensors/sensor-types#auto_axes Use evs_configuration.dtd with xmllint tool, to validate XML configuration file --> <configuration> <!-- system configuration --> <system> <!-- reference dimension of the vehicle in the unit of centimeters --> <dimension x='200' y='400' z='100' /> <!-- number of cameras available to EVS --> <num_cameras value='2'/> <!-- list of supported use cases --> <supported_use_case> <!-- use case configuration --> <use_case id='rear_view' camera='/dev/video1' stream_id='1' /> <!-- use case configuration --> <use_case id='surround_view' camera='group1' stream_id='0' /> </supported_use_case> </system> <!-- camera device information --> <camera> <!-- camera group 0 --> <group group_id='group0' device_id='/dev/video1,/dev/video2' synchronized='false' > <caps> <stream id='0' width='640' height='360' format='V4L2_PIX_UYUV'/> </caps> </group> <!-- camera device starts --> <device id='/dev/video1' position='rear'> <caps> <!-- list of supported controls --> <supported_controls value='BRIGHTNESS, CONTRAST, AUTO_WHITE_BALANCE, WHITE_BALANCE_TEMPERATURE, SHARPNESS, AUTO_EXPOSURE, ABSOLUTE_EXPOSURE, AUTO_FOCUS, ABSOLUTE_ZOOM' /> <!-- list of supported stream configurations --> <stream id='0' width='1280' height='1080' format='V4L2_PIX_NV21'/> <stream id='1' width='1280' height='1080' format='V4L2_PIX_YUYV'/> <stream id='2' width='1280' height='1080' format='V4L2_PIX_UYUV'/> <stream id='3' width='640' height='360' format='V4L2_PIX_NV21'/> <stream id='4' width='640' height='360' format='V4L2_PIX_YUYV'/> <stream id='5' width='640' height='360' format='V4L2_PIX_UYUV'/> <stream id='6' width='320' height='240' format='V4L2_PIX_NV21'/> <stream id='7' width='320' height='240' format='V4L2_PIX_YUYV'/> <stream id='8' width='320' height='240' format='V4L2_PIX_UYUV'/> </caps> <!-- list of parameters --> <characteristics> <!-- Lens distortion information. See https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html#LENS_DISTORTION --> <parameter name='LENS_DISTORTION' type='float' size='5' value='0.0,0.0,0.0,0.0,0.0' /> <!-- Camera intrinsic calibration matrix. See https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html#LENS_INTRINSIC_CALIBRATION --> <parameter name='LENS_INTRINSIC_CALIBRATION' type='float' size='5' value='0.0,0.0,0.0,0.0,0.0' /> <!-- Camera pose translation and rotation. See https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html#LENS_POSE_TRANSLATION https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html#LENS_POSE_ROTATION --> <parameter name='LENS_POSE_TRANSLATION' type='float' size='3' value='0.0,0.0,0.0' /> <parameter name='LENS_POSE_ROTATION' type='float' size='4' value='0.0,0.0,0.0,0.0' /> </characteristics> </device> <device id='/dev/video2' position='front'> <caps> <!-- list of supported stream configurations --> <stream id='0' width='1280' height='1080' format='V4L2_PIX_NV21'/> </caps> </device> </camera> <!-- display device starts --> <display> <display_device id='display0' position='driver'> <!-- list of supported input formats This must be a subset of android_pixel_format_t enum. --> <supported_formats value='RGBA_8888, YUYV, UYVY' /> </display_device> </display> </configuration>