How to get class and bounding box coordinates from YOLOv5 predictions?

Question

I am trying to perform inference on my custom YOLOv5 model. The official documentation uses the default detect.py script for inference. I have written my own python script but I cannot access the predicted class and the bounding box coordinates from the output of the model. Here is my code:

import torch
    
model = torch.hub.load('ultralytics/yolov5', 'custom', path_or_model='best.pt') 
predictions = model("my_image.png")

print(predictions)

Answer 1

YOLOv5 PyTorch Hub models allow for simple model loading and inference in a pure python environment without using detect.py .

Simple Inference Example

This example loads a pretrained YOLOv5s model from PyTorch Hub as model and passes an image for inference. 'yolov5s' is the YOLOv5 'small' model. For details on all available models please see the README . Custom models can also be loaded, including custom trained PyTorch models and their exported variants, ie ONNX, TensorRT, TensorFlow, OpenVINO YOLOv5 models.

import torch

# Model
model = torch.hub.load('ultralytics/yolov5', 'yolov5s')  # or yolov5m, yolov5l, yolov5x, etc.
# model = torch.hub.load('ultralytics/yolov5', 'custom', 'path/to/best.pt')  # custom trained model

# Images
im = 'https://ultralytics.com/images/zidane.jpg'  # or file, Path, URL, PIL, OpenCV, numpy, list

# Inference
results = model(im)

# Results
results.print()  # or .show(), .save(), .crop(), .pandas(), etc.

results.xyxy[0]  # im predictions (tensor)
results.pandas().xyxy[0]  # im predictions (pandas)
#      xmin    ymin    xmax   ymax  confidence  class    name
# 0  749.50   43.50  1148.0  704.5    0.874023      0  person
# 2  114.75  195.75  1095.0  708.0    0.624512      0  person
# 3  986.00  304.00  1028.0  420.0    0.286865     27     tie

See YOLOv5 PyTorch Hub Tutorial for details.

Answer 2

results = model(input_images)
labels, cord_thres = results.xyxyn[0][:, -1].numpy(), results.xyxyn[0][:, :-1].numpy()

This will give you labels, coordinates, and thresholds for each object detected, you can use it to plot bounding boxes. You can check out this repo for more detailed code.

https://github.com/akash-agni/Real-Time-Object-Detection