snipplets.dev/projects/OpenVINO/Python/infer.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright (C) 2018-2023 Intel Corporation
# SPDX-License-Identifier: Apache-2.0

# https://docs.openvino.ai/2023.3/openvino_sample_hello_reshape_ssd.html

import logging as log
import os
import sys

import cv2
import numpy as np
import openvino as ov


def main():
    log.basicConfig(format='[ %(levelname)s ] %(message)s', level=log.INFO, stream=sys.stdout)

    # Parsing and validation of input arguments
    if len(sys.argv) != 4:
        log.info(f'Usage: {sys.argv[0]} <path_to_model> <path_to_image> <device_name>')
        return 1

    model_path = sys.argv[1]
    image_path = sys.argv[2]
    device_name = sys.argv[3]

# --------------------------- Step 1. Initialize OpenVINO Runtime Core ------------------------------------------------
    log.info('Creating OpenVINO Runtime Core')
    core = ov.Core()

# --------------------------- Step 2. Read a model --------------------------------------------------------------------
    log.info(f'Reading the model: {model_path}')
    # (.xml and .bin files) or (.onnx file)
    model = core.read_model(model_path)

    if len(model.inputs) != 1:
        log.error('Sample supports only single input topologies')
        return -1

    if len(model.outputs) != 1:
        log.error('Sample supports only single output topologies')
        return -1

# --------------------------- Step 3. Set up input --------------------------------------------------------------------
    # Read input image
    image = cv2.imread(image_path)
    # Add N dimension
    input_tensor = np.expand_dims(image, 0)

    log.info('Reshaping the model to the height and width of the input image')
    n, h, w, c = input_tensor.shape
    model.reshape({model.input().get_any_name(): ov.PartialShape((n, c, h, w))})

# --------------------------- Step 4. Apply preprocessing -------------------------------------------------------------
    ppp = ov.preprocess.PrePostProcessor(model)

    # 1) Set input tensor information:
    # - input() provides information about a single model input
    # - precision of tensor is supposed to be 'u8'
    # - layout of data is 'NHWC'
    ppp.input().tensor() \
        .set_element_type(ov.Type.u8) \
        .set_layout(ov.Layout('NHWC'))  # noqa: N400

    # 2) Here we suppose model has 'NCHW' layout for input
    ppp.input().model().set_layout(ov.Layout('NCHW'))

    # 3) Set output tensor information:
    # - precision of tensor is supposed to be 'f32'
    ppp.output().tensor().set_element_type(ov.Type.f32)

    # 4) Apply preprocessing modifing the original 'model'
    model = ppp.build()

# ---------------------------Step 4. Loading model to the device-------------------------------------------------------
    log.info('Loading the model to the plugin')
    compiled_model = core.compile_model(model, device_name)

# --------------------------- Step 6. Create infer request and do inference synchronously -----------------------------
    log.info('Starting inference in synchronous mode')
    results = compiled_model.infer_new_request({0: input_tensor})

# ---------------------------Step 6. Process output--------------------------------------------------------------------
    predictions = next(iter(results.values()))

    # Change a shape of a numpy.ndarray with results ([1, 1, N, 7]) to get another one ([N, 7]),
    # where N is the number of detected bounding boxes
    detections = predictions.reshape(-1, 7)

    for detection in detections:
        confidence = detection[2]

        if confidence > 0.5:
            class_id = int(detection[1])

            xmin = int(detection[3] * w)
            ymin = int(detection[4] * h)
            xmax = int(detection[5] * w)
            ymax = int(detection[6] * h)

            log.info(f'Found: class_id = {class_id}, confidence = {confidence:.2f}, ' f'coords = ({xmin}, {ymin}), ({xmax}, {ymax})')

            # Draw a bounding box on a output image
            cv2.rectangle(image, (xmin, ymin), (xmax, ymax), (0, 255, 0), 2)

    cv2.imwrite('out.bmp', image)

    if os.path.exists('out.bmp'):
        log.info('Image out.bmp was created!')
    else:
        log.error('Image out.bmp was not created. Check your permissions.')

# ----------------------------------------------------------------------------------------------------------------------
    log.info('This sample is an API example, for any performance measurements please use the dedicated benchmark_app tool\n')
    return 0


if __name__ == '__main__':
    sys.exit(main())