Face Detection

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The Face Detection API provides functions to detect face information about stored image files.

Required Header

#include <media_content.h>

Related Features

This API is related with the following feature:

• http://tizen.org/feature/vision.face_recognition It is recommended to create applications with regard to features, to increase reliability.
  

You can check if a device supports the related features for this API by using System Information, thereby controlling the procedure of your application.

To ensure your application is only running on a device with specific features, please define the features in your manifest file using the manifest editor in the SDK.

More details on featuring your application can be found from Feature Element.

Overview

The Face Detection API provides functions to detect face information associated with image files.
Face information detected by mediavision API. To detect faces, you should use media_info_start_face_detection() API.

API allows to:

• start and cancel face detection with image files

To obtain the media handle (media_info_h), call the media_info_create() function.
To start face detection, call the media_info_start_face_detection() function.
To cancel face detection after it's been started, call the media_info_cancel_face_detection() function.

Functions
int	media_info_start_face_detection (media_info_h media, media_face_detection_completed_cb callback, void *user_data)
	Starts face detection for the given image, asynchronously.
int	media_info_cancel_face_detection (media_info_h media)
	Cancels face detection of image for the given media.
Typedefs
typedef void(*	media_face_detection_completed_cb )(media_content_error_e error, const int face_count, void *user_data)
	Called when face detection on the image is completed.

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Typedef Documentation

typedef void(* media_face_detection_completed_cb)(media_content_error_e error, const int face_count, void *user_data)

Called when face detection on the image is completed.

The following error codes can be delivered.
MEDIA_CONTENT_ERROR_NONE,
MEDIA_CONTENT_ERROR_OUT_OF_MEMORY,
MEDIA_CONTENT_ERROR_INVALID_OPERATION,
MEDIA_CONTENT_ERROR_DB_FAILED,
MEDIA_CONTENT_ERROR_DB_BUSY,
MEDIA_CONTENT_ERROR_UNSUPPORTED_CONTENT

Since :

3.0

Remarks:

The callback is called in a separate thread(not in the main loop).

Parameters:

[in]	error	The error code
[in]	face_count	The number of all detected faces
[in]	user_data	The user data passed from the foreach function

Precondition:

media_info_start_face_detection()

See also:

media_info_start_face_detection()

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Function Documentation

int media_info_cancel_face_detection

(

media_info_h

media

)

Cancels face detection of image for the given media.

This function cancels face detection for given media item.
If you cancel face detection request before callback is invoked, the callback registered by media_info_start_face_detection() function will not be invoked.

Since :

3.0

Privilege Level:

public

Privilege:

http://tizen.org/privilege/content.write

Remarks:

If face detection is already done when you request the cancellation, this function return MEDIA_CONTENT_ERROR_INVALID_OPERATION

Parameters:

[in]

media

The handle to the media info

Returns:

0 on success, otherwise a negative error value

Return values:

MEDIA_CONTENT_ERROR_NONE	Successful
MEDIA_CONTENT_ERROR_INVALID_PARAMETER	Invalid parameter
MEDIA_CONTENT_ERROR_PERMISSION_DENIED	Permission denied
MEDIA_CONTENT_ERROR_INVALID_OPERATION	Invalid operation

Precondition:

This function requires opened connection to content service by media_content_connect().

See also:

media_content_connect()

media_info_start_face_detection()

int media_info_start_face_detection	(	media_info_h	media,
		media_face_detection_completed_cb	callback,
		void *	user_data
	)

Starts face detection for the given image, asynchronously.

This function detects faces for given image item and calls the given callback function when the detection is completed.
The given callback function is called when the detection is completed.
To obtain the detected faces, call the media_info_foreach_face_from_db() function.

Since :

3.0

Privilege Level:

public

Privilege:

http://tizen.org/privilege/content.write
http://tizen.org/privilege/mediastorage
http://tizen.org/privilege/externalstorage

Remarks:

If you want to destroy the media handle before callback invoked, you must cancel the face detection request by using media_info_cancel_face_detection().
If face detection fails, the face_count argument in media_face_detection_completed_cb() will be set to 0. Media items in external storage are not supported, with the exception of MMC items.

Parameters:

[in]	media	The handle to the media info
[in]	callback	The callback function to be invoked when detection is completed
[in]	user_data	The user data to be passed to the callback function

Returns:

0 on success, otherwise a negative error value

Return values:

MEDIA_CONTENT_ERROR_NONE	Successful
MEDIA_CONTENT_ERROR_INVALID_PARAMETER	Invalid parameter
MEDIA_CONTENT_ERROR_OUT_OF_MEMORY	Out of memory
MEDIA_CONTENT_ERROR_INVALID_OPERATION	Invalid operation
MEDIA_CONTENT_ERROR_DB_FAILED	DB Operation failed
MEDIA_CONTENT_ERROR_DB_BUSY	DB Operation busy
MEDIA_CONTENT_ERROR_NETWORK	Network fail
MEDIA_CONTENT_ERROR_PERMISSION_DENIED	Permission denied
MEDIA_CONTENT_ERROR_NOT_SUPPORTED	Not supported

Precondition:

This function requires opened connection to content service by media_content_connect().

See also:

media_content_connect()

media_info_cancel_face_detection()