image_reader.h

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// ----------------------------------------------------------------------------
// -                        CloudViewer: www.cloudViewer.org                  -
// ----------------------------------------------------------------------------
// Copyright (c) 2018-2024 www.cloudViewer.org
// SPDX-License-Identifier: MIT
// ----------------------------------------------------------------------------
 
#pragma once
 
#include <unordered_set>
 
#include "base/database.h"
#include "util/bitmap.h"
#include "util/threading.h"
 
namespace colmap {
 
struct ImageReaderOptions {
    // Path to database in which to store the extracted data.
    std::string database_path = "";
 
    // Root path to folder which contains the images.
    std::string image_path = "";
 
    // Optional root path to folder which contains image masks. For a given
    // image, the corresponding mask must have the same sub-path below this root
    // as the image has below image_path. The filename must be equal, aside from
    // the added extension .png. For example, for an image
    // image_path/abc/012.jpg, the mask would be mask_path/abc/012.jpg.png. No
    // features will be extracted in regions where the mask image is black
    // (pixel intensity value 0 in grayscale).
    std::string mask_path = "";
 
    // Optional list of images to read. The list must contain the relative path
    // of the images with respect to the image_path.
    std::vector<std::string> image_list;
 
    // Name of the camera model.
    std::string camera_model = "SIMPLE_RADIAL";
 
    // Whether to use the same camera for all images.
    bool single_camera = false;
 
    // Whether to use the same camera for all images in the same sub-folder.
    bool single_camera_per_folder = false;
 
    // Whether to use a different camera for each image.
    bool single_camera_per_image = false;
 
    // Whether to explicitly use an existing camera for all images. Note that in
    // this case the specified camera model and parameters are ignored.
    int existing_camera_id = kInvalidCameraId;
 
    // Manual specification of camera parameters. If empty, camera parameters
    // will be extracted from EXIF, i.e. principal point and focal length.
    std::string camera_params = "";
 
    // If camera parameters are not specified manually and the image does not
    // have focal length EXIF information, the focal length is set to the
    // value `default_focal_length_factor * max(width, height)`.
    double default_focal_length_factor = 1.2;
 
    // Optional path to an image file specifying a mask for all images. No
    // features will be extracted in regions where the mask is black (pixel
    // intensity value 0 in grayscale).
    std::string camera_mask_path = "";
 
    bool Check() const;
};
 
// Recursively iterate over the images in a directory. Skips an image if it
// already exists in the database. Extracts the camera intrinsics from EXIF and
// writes the camera information to the database.
class ImageReader {
public:
    enum class Status {
        FAILURE,
        SUCCESS,
        IMAGE_EXISTS,
        BITMAP_ERROR,
        CAMERA_SINGLE_DIM_ERROR,
        CAMERA_EXIST_DIM_ERROR,
        CAMERA_PARAM_ERROR
    };
 
    ImageReader(const ImageReaderOptions& options, Database* database);
 
    Status Next(Camera* camera, Image* image, Bitmap* bitmap, Bitmap* mask);
    size_t NextIndex() const;
    size_t NumImages() const;
 
private:
    // Image reader options.
    ImageReaderOptions options_;
    Database* database_;
    // Index of previously processed image.
    size_t image_index_;
    // Previously processed camera.
    Camera prev_camera_;
    std::unordered_map<std::string, camera_t> camera_model_to_id_;
    // Names of image sub-folders.
    std::string prev_image_folder_;
    std::unordered_set<std::string> image_folders_;
};
 
}  // namespace colmap