# ObjectDetector

# Copyright (C) 2024-2026 Collabora Ltd.

#

# This library is free software; you can redistribute it and/or

# modify it under the terms of the GNU Library General Public

# License as published by the Free Software Foundation; either

# version 2 of the License, or (at your option) any later version.

#

# This library is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

# Library General Public License for more details.

#

# You should have received a copy of the GNU Library General Public

# License along with this library; if not, write to the

# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,

# Boston, MA 02110-1301, USA.

from base_objectdetector import BaseObjectDetector

from backend import GObject

import backend

class ObjectDetector(BaseObjectDetector):

"""

GStreamer element for a general object detector where the user sets the model-name property.

"""

__gstmetadata__ = (

"ObjectDetector",

"Transform",

"General purpose object",

"Aaron Boxer <aaron.boxer@collabora.com>",

)

confidence = GObject.Property(

type=float,

default=0.25,

minimum=0.0,

maximum=1.0,

nick="Confidence Threshold",

blurb="Minimum detection confidence for the decoder post-process "

"(anchor_free); lower = more (and weaker) detections",

flags=GObject.ParamFlags.READWRITE,

)

nms_iou = GObject.Property(

type=float,

default=0.45,

minimum=0.0,

maximum=1.0,

nick="NMS IoU",

blurb="NMS IoU threshold for the decoder post-process; higher keeps "

"more overlapping boxes",

flags=GObject.ParamFlags.READWRITE,

)

def __init__(self):

super().__init__()

self.logger.info(

"ObjectDetector created without a model. Please set the 'model-name' property."

)

def do_forward(self, frames):

# Push decoder thresholds to the engine before it post-processes.

if self.engine:

self.engine.conf = self.confidence

self.engine.iou = self.nms_iou

return super().do_forward(frames)

# The class is backend-agnostic: under g2g the host imports this module and

# instantiates ObjectDetector directly, so no GObject registration applies.

# GStreamer factory registration runs only under the gst backend.

if backend.BACKEND == "gst":

__gstelementfactory__ = backend.register_gst_element(

"pyml_objectdetector", ObjectDetector

)