GstInference/Metadatas/GstDetectionMeta

GstInference
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InceptionV1 InceptionV2 InceptionV3 InceptionV4 TinyYoloV2 TinyYoloV3 YoloV2 ResNetV1 MobileNetV2 MobileNetV2 + SSD AlexNet
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GstClassificationMeta GstInferenceMeta Signals
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This metadata consist on an array of bounding boxes, that were previously filtered on the detection element to remove low probability and duplicated boxes.

Fields

All detection elements on GstInference use the same metadata standard. GstDetectionMeta consist on the following fields:

field	type	description
num_boxes	gint	The number of boxes outputted by the model. This can vary over time.
boxes	BBox *	The array of bounding boxes.

Each bounding box is an struct with:

field	type	description
label	gint	The label represented.
prob	gdouble	The probability of the box. Note that probability on detection works different from classification. This probability does not reflect actual probability but rather the certainty level of the neural network.
x	gdouble	X coordinate (top left corner)
y	gdouble	Y coordinate (top left corner)
width	gdouble	Box width
height	gdouble	Box height

Access metadata

If you want to access this metadata from your custom Gstreamer element instead the process is fairly easy:

1. Add a GstInference detection element such as TinyYoloV2 to your pipeline
2. Include GstInference metadata header: #include "gst/r2inference/gstinferencemeta.h"
3. Get a GstDetectionMeta object from the buffer: detect_meta = (GstDetectionMeta *) gst_buffer_get_meta (frame->buffer, GST_DETECTION_META_API_TYPE);

All GstInference detection elements also raise a signal containing GstDetectionMeta, for details on how to use this signal please check the example applications section.