common/api.py

import cv2
import torch
import warnings
import numpy as np
from pathlib import Path
from typing import Dict, Any, Optional, Tuple, List, Union
from hloc import logger
from hloc import match_dense, match_features, extract_features
from hloc.utils.viz import add_text, plot_keypoints
from .utils import (
    load_config,
    get_model,
    get_feature_model,
    filter_matches,
    device,
    ROOT,
)
from .viz import (
    fig2im,
    plot_images,
    display_matches,
)
import matplotlib.pyplot as plt

warnings.simplefilter("ignore")


class ImageMatchingAPI(torch.nn.Module):
    default_conf = {
        "dense": True,
        "matcher": {
            "model": {
                "name": "topicfm",
                "match_threshold": 0.2,
            }
        },
        "feature": {
            "model": {
                "name": "xfeat",
                "max_keypoints": 1024,
                "keypoint_threshold": 0.015,
            }
        },
        "ransac": {
            "enable": True,
            "estimator": "poselib",
            "geometry": "homography",
            "method": "RANSAC",
            "reproj_threshold": 3,
            "confidence": 0.9999,
            "max_iter": 10000,
        },
    }

    def __init__(
        self,
        conf: dict = {},
        device: str = "cpu",
        detect_threshold: float = 0.015,
        max_keypoints: int = 1024,
        match_threshold: float = 0.2,
    ) -> None:
        """
        Initializes an instance of the ImageMatchingAPI class.

        Args:
            conf (dict): A dictionary containing the configuration parameters.
            device (str, optional): The device to use for computation. Defaults to "cpu".
            detect_threshold (float, optional): The threshold for detecting keypoints. Defaults to 0.015.
            max_keypoints (int, optional): The maximum number of keypoints to extract. Defaults to 1024.
            match_threshold (float, optional): The threshold for matching keypoints. Defaults to 0.2.

        Returns:
            None
        """
        super().__init__()
        self.device = device
        self.conf = conf = {
            **self.parse_match_config(self.default_conf),
            **conf,
        }
        self._updata_config(detect_threshold, max_keypoints, match_threshold)
        self._init_models()
        self.pred = None

    def parse_match_config(self, conf):
        if conf["dense"]:
            return {
                **conf,
                "matcher": match_dense.confs.get(
                    conf["matcher"]["model"]["name"]
                ),
                "dense": True,
            }
        else:
            return {
                **conf,
                "feature": extract_features.confs.get(
                    conf["feature"]["model"]["name"]
                ),
                "matcher": match_features.confs.get(
                    conf["matcher"]["model"]["name"]
                ),
                "dense": False,
            }

    def _updata_config(
        self,
        detect_threshold: float = 0.015,
        max_keypoints: int = 1024,
        match_threshold: float = 0.2,
    ):
        self.dense = self.conf["dense"]
        if self.conf["dense"]:
            self.conf["matcher"]["model"]["match_threshold"] = match_threshold
        else:
            self.conf["feature"]["model"]["max_keypoints"] = max_keypoints
            self.conf["feature"]["model"][
                "keypoint_threshold"
            ] = detect_threshold
        self.match_conf = self.conf["matcher"]
        self.extract_conf = self.conf["feature"]

    def _init_models(self):
        # initialize matcher
        self.matcher = get_model(self.conf["matcher"])
        # initialize extractor
        if self.dense:
            self.extractor = None
        else:
            self.extractor = get_feature_model(self.conf["feature"])

    def _forward(self, img0, img1):
        if self.dense:
            pred = match_dense.match_images(
                self.matcher,
                img0,
                img1,
                self.match_conf["preprocessing"],
                device=self.device,
            )
            last_fixed = "{}".format(self.match_conf["model"]["name"])
        else:
            pred0 = extract_features.extract(
                self.extractor, img0, self.extract_conf["preprocessing"]
            )
            pred1 = extract_features.extract(
                self.extractor, img1, self.extract_conf["preprocessing"]
            )
            pred = match_features.match_images(self.matcher, pred0, pred1)
        return pred

    @torch.inference_mode()
    def forward(
        self,
        img0: np.ndarray,
        img1: np.ndarray,
    ) -> Dict[str, np.ndarray]:
        """
        Forward pass of the image matching API.

        Args:
            img0: A 3D NumPy array of shape (H, W, C) representing the first image.
                  Values are in the range [0, 1] and are in RGB mode.
            img1: A 3D NumPy array of shape (H, W, C) representing the second image.
                  Values are in the range [0, 1] and are in RGB mode.

        Returns:
            A dictionary containing the following keys:
            - image0_orig: The original image 0.
            - image1_orig: The original image 1.
            - keypoints0_orig: The keypoints detected in image 0.
            - keypoints1_orig: The keypoints detected in image 1.
            - mkeypoints0_orig: The raw matches between image 0 and image 1.
            - mkeypoints1_orig: The raw matches between image 1 and image 0.
            - mmkeypoints0_orig: The RANSAC inliers in image 0.
            - mmkeypoints1_orig: The RANSAC inliers in image 1.
            - mconf: The confidence scores for the raw matches.
            - mmconf: The confidence scores for the RANSAC inliers.
        """
        # Take as input a pair of images (not a batch)
        assert isinstance(img0, np.ndarray)
        assert isinstance(img1, np.ndarray)
        self.pred = self._forward(img0, img1)
        if self.conf["ransac"]["enable"]:
            self.pred = self._geometry_check(self.pred)
        return self.pred

    def _geometry_check(
        self,
        pred: Dict[str, Any],
    ) -> Dict[str, Any]:
        """
        Filter matches using RANSAC. If keypoints are available, filter by keypoints.
        If lines are available, filter by lines. If both keypoints and lines are
        available, filter by keypoints.

        Args:
            pred (Dict[str, Any]): dict of matches, including original keypoints.
                                  See :func:`filter_matches` for the expected keys.

        Returns:
            Dict[str, Any]: filtered matches
        """
        pred = filter_matches(
            pred,
            ransac_method=self.conf["ransac"]["method"],
            ransac_reproj_threshold=self.conf["ransac"]["reproj_threshold"],
            ransac_confidence=self.conf["ransac"]["confidence"],
            ransac_max_iter=self.conf["ransac"]["max_iter"],
        )
        return pred

    def visualize(
        self,
        log_path: Optional[Path] = None,
    ) -> None:
        """
        Visualize the matches.

        Args:
            log_path (Path, optional): The directory to save the images. Defaults to None.

        Returns:
            None
        """
        if self.conf["dense"]:
            postfix = str(self.conf["matcher"]["model"]["name"])
        else:
            postfix = "{}_{}".format(
                str(self.conf["feature"]["model"]["name"]),
                str(self.conf["matcher"]["model"]["name"]),
            )
        titles = [
            "Image 0 - Keypoints",
            "Image 1 - Keypoints",
        ]
        pred: Dict[str, Any] = self.pred
        image0: np.ndarray = pred["image0_orig"]
        image1: np.ndarray = pred["image1_orig"]
        output_keypoints: np.ndarray = plot_images(
            [image0, image1], titles=titles, dpi=300
        )
        if (
            "keypoints0_orig" in pred.keys()
            and "keypoints1_orig" in pred.keys()
        ):
            plot_keypoints([pred["keypoints0_orig"], pred["keypoints1_orig"]])
            text: str = (
                f"# keypoints0: {len(pred['keypoints0_orig'])} \n"
                + f"# keypoints1: {len(pred['keypoints1_orig'])}"
            )
            add_text(0, text, fs=15)
        output_keypoints = fig2im(output_keypoints)
        # plot images with raw matches
        titles = [
            "Image 0 - Raw matched keypoints",
            "Image 1 - Raw matched keypoints",
        ]
        output_matches_raw, num_matches_raw = display_matches(
            pred, titles=titles, tag="KPTS_RAW"
        )
        # plot images with ransac matches
        titles = [
            "Image 0 - Ransac matched keypoints",
            "Image 1 - Ransac matched keypoints",
        ]
        output_matches_ransac, num_matches_ransac = display_matches(
            pred, titles=titles, tag="KPTS_RANSAC"
        )
        if log_path is not None:
            img_keypoints_path: Path = log_path / f"img_keypoints_{postfix}.png"
            img_matches_raw_path: Path = (
                log_path / f"img_matches_raw_{postfix}.png"
            )
            img_matches_ransac_path: Path = (
                log_path / f"img_matches_ransac_{postfix}.png"
            )
            cv2.imwrite(
                str(img_keypoints_path),
                output_keypoints[:, :, ::-1].copy(),  # RGB -> BGR
            )
            cv2.imwrite(
                str(img_matches_raw_path),
                output_matches_raw[:, :, ::-1].copy(),  # RGB -> BGR
            )
            cv2.imwrite(
                str(img_matches_ransac_path),
                output_matches_ransac[:, :, ::-1].copy(),  # RGB -> BGR
            )
            plt.close("all")


if __name__ == "__main__":
    import argparse

    config = load_config(ROOT / "common/config.yaml")
    test_api(config)