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DetectionProcessor class

DetectionProcessor

A class for processing detection results and transforming them using available utility methods. This class takes the output from an object detection model (e.g., YOLOv8) and provides functionality to separate, process, and visualize detected color checker cards and their patches.

Source code in color_correction/processor/detection.py 
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class DetectionProcessor:
    """
    A class for processing detection results and transforming them using
    available utility methods. This class takes the output from an object
    detection model (e.g., YOLOv8) and provides functionality to separate,
    process, and visualize detected color checker cards and their patches.
    """

    @staticmethod
    def get_each_class_box(
        prediction: DetectionResult,
    ) -> tuple[list[BoundingBox], list[BoundingBox]]:
        """
        Separates detection boxes into card boxes and patch boxes.

        Parameters
        ----------
        prediction : DetectionResult
            The detection output that includes bounding boxes and class IDs.

        Returns
        -------
        tuple[list[BoundingBox], list[BoundingBox]]
            A tuple containing:

            - a list of card boxes (class id 1)
            - a list of patch boxes (class id 0).
        """
        ls_cards = [
            box
            for box, class_id in zip(
                prediction.boxes,
                prediction.class_ids,
                strict=False,
            )
            if class_id == 1
        ]
        ls_patches = [
            box
            for box, class_id in zip(
                prediction.boxes,
                prediction.class_ids,
                strict=False,
            )
            if class_id == 0
        ]
        return ls_cards, ls_patches

    @staticmethod
    def print_summary(prediction: DetectionResult) -> None:
        """
        Prints a summary of the detected cards and patches.

        Parameters
        ----------
        prediction : DetectionResult
            The detection result to summarize.
        """
        ls_cards, ls_patches = DetectionProcessor.get_each_class_box(prediction)
        print(f"Number of cards detected: {len(ls_cards)}")
        print(f"Number of patches detected: {len(ls_patches)}")

    @staticmethod
    def process_patches(
        input_image: ImageBGR,
        ordered_patches: list[tuple[BoundingBox, tuple[int, int]] | None],
    ) -> tuple[list[ColorPatchType], ImageBGR]:
        """
        Processes each detected patch by extracting its region from the image,
        computing its mean BGR color, and building a visualization grid.

        Parameters
        ----------
        input_image : ImageBGR
            The original image containing detected patches.
        ordered_patches : list[tuple[BoundingBox, tuple[int, int]] | None]
            The list of ordered patch coordinates paired with their center
            points, possibly with missing entries as None.

        Returns
        -------
        tuple[list[ColorPatchType], ImageBGR]
            a tuple containing:

            - list of mean BGR color values for each patch.
            - an image visualizing these patches in a grid layout.
        """
        patch_size = (50, 50, 1)
        ls_bgr_mean_patch = []
        ls_horizontal_patch = []
        ls_vertical_patch = []

        for idx, coord_patch in enumerate(ordered_patches, start=1):
            if coord_patch is None:
                continue

            bbox_patch, _ = coord_patch

            # Extract and process each patch
            cropped_patch = crop_region_with_margin(
                image=input_image,
                coordinates=bbox_patch,
                margin_ratio=0.2,
            )
            bgr_mean_patch = calc_mean_color_patch(cropped_patch)
            ls_bgr_mean_patch.append(bgr_mean_patch)

            # Build visualization
            patch_viz = np.tile(bgr_mean_patch, patch_size)
            ls_horizontal_patch.append(patch_viz)
            if idx % 6 == 0:
                ls_vertical_patch.append(np.hstack(ls_horizontal_patch))
                ls_horizontal_patch = []

        patches_image = np.vstack(ls_vertical_patch)
        return ls_bgr_mean_patch, patches_image

    @staticmethod
    def extract_color_patches(
        input_image: ImageBGR,
        prediction: DetectionResult,
        draw_processed_image: bool = False,
    ) -> tuple[list[ColorPatchType], ImageBGR, ImageBGR | None]:
        """
        Extracts and processes color patches from detected color checker cards,
        transforming the detection results with available methods.

        The method first separates detected cards and patches, generates an expected
        patch grid, and then matches the detected patches with this grid. If patches
        are missing, it attempts to auto-fill them with suggested coordinates.
        Finally, it computes the mean color for each patch and builds a visualization.

        Parameters
        ----------
        input_image : ImageBGR
            The original image containing the color checker card.
        prediction : DetectionResult
            The detection result output from the model.
        draw_processed_image : bool, optional
            If True, returns an additional image with visualized detections.
            Otherwise, only patch processing is performed. Defaults to False.

        Returns
        -------
        tuple[list[ColorPatchType], ImageBGR, ImageBGR | None]
            a tuple containing:

            - a list of mean BGR color values for each patch.
            - an image visualizing these patches in a grid layout.
            - an optional image with visualized detection results.

        Raises
        ------
        ValueError
            If no cards or patches are detected.
        """
        ls_cards, ls_patches = DetectionProcessor.get_each_class_box(prediction)

        if not ls_cards:
            raise ValueError("No cards detected")
        if not ls_patches:
            raise ValueError("No patches detected")

        # Generate expected patch grid
        card_box = ls_cards[0]
        ls_grid_card = generate_expected_patches(card_box)

        # Match detected patches with grid
        ls_ordered_patch_bbox = extract_intersecting_patches(
            ls_patches=ls_patches,
            ls_grid_card=ls_grid_card,
        )

        # Handle missing patches
        d_suggest = None
        if None in ls_ordered_patch_bbox:
            print("Auto filling missing patches...")
            ls_ordered_bbox_only = [
                patch[0] if patch is not None else None
                for patch in ls_ordered_patch_bbox
            ]
            d_suggest = suggest_missing_patch_coordinates(ls_ordered_bbox_only)
            for idx, patch in d_suggest.items():
                cxpatch = (patch[0] + patch[2]) // 2
                cypatch = (patch[1] + patch[3]) // 2
                ls_ordered_patch_bbox[idx] = (patch, (cxpatch, cypatch))

        # Process patches and create visualizations
        ls_bgr_mean_patch, grid_patch_img = DetectionProcessor.process_patches(
            input_image=input_image,
            ordered_patches=ls_ordered_patch_bbox,
        )

        detection_viz = None
        if draw_processed_image:
            detection_viz = DetectionProcessor.draw_preprocess(
                image=input_image,
                expected_boxes=ls_grid_card,
                prediction=prediction,
                ls_ordered_patch_bbox=ls_ordered_patch_bbox,
                suggested_patches=d_suggest,
            )

        return ls_bgr_mean_patch, grid_patch_img, detection_viz

    @staticmethod
    def draw_preprocess(
        image: ImageBGR,
        expected_boxes: list[BoundingBox],
        prediction: DetectionResult,
        ls_ordered_patch_bbox: list[BoundingBox | None],
        suggested_patches: dict[int, BoundingBox] | None = None,
    ) -> ImageBGR:
        """
        Draws visualizations on the input image to compare the detected patches with
        the expected positions. It overlays expected boxes, connects detected patches to
        their corresponding expected boxes, and highlights individual patch detections.

        Parameters
        ----------
        image : ImageBGR
            The original image to draw on.
        expected_boxes : list[BoundingBox]
            List of expected bounding boxes for patches.
        prediction : DetectionResult
            The detection results containing predicted bounding boxes.
        ls_ordered_patch_bbox : list[BoundingBox | None]
            The list of ordered patch bounding boxes.
        suggested_patches : dict[int, BoundingBox], optional
            Dictionary of suggested patch coordinates for missing patches.

        Returns
        -------
        ImageBGR
            The image with drawn detection and patch visualizations.
        """
        color_green = (0, 255, 0)
        color_cyan = (255, 255, 10)
        color_violet = (255, 0, 255)
        color_red = (0, 0, 255)
        color_blue = (255, 0, 0)

        result_image = image.copy()

        # Draw all expected boxes
        for idx_b, box in enumerate(expected_boxes):
            cv2.rectangle(
                img=result_image,
                pt1=(box[0], box[1]),
                pt2=(box[2], box[3]),
                color=color_green,
                thickness=2,
            )

            # Draw connection lines between expected and detected patch boxes
            patch = ls_ordered_patch_bbox[idx_b]
            if patch is None:
                continue
            cx, cy = patch[1]
            crefx, crefy = (box[0] + box[2]) // 2, (box[1] + box[3]) // 2
            cv2.line(
                img=result_image,
                pt1=(cx, cy),
                pt2=(crefx, crefy),
                color=color_blue,
                thickness=1,
            )

        # Draw all predicted boxes
        for pbox, pids, pscore in zip(
            prediction.boxes,
            prediction.class_ids,
            prediction.scores,
            strict=False,
        ):
            if pids == 1:
                continue
            cv2.rectangle(
                img=result_image,
                pt1=(pbox[0], pbox[1]),
                pt2=(pbox[2], pbox[3]),
                color=color_cyan,
                thickness=2,
            )
            cv2.putText(
                img=result_image,
                text=f"{pids} {pscore:.2f}",
                org=(pbox[0] + 3, pbox[1] + 12),
                fontFace=cv2.FONT_HERSHEY_SIMPLEX,
                fontScale=0.4,
                color=color_red,
                thickness=1,
                lineType=cv2.LINE_AA,
            )

        # Draw suggested patches if provided
        if suggested_patches:
            for box in suggested_patches.values():
                cv2.rectangle(
                    img=result_image,
                    pt1=(box[0], box[1]),
                    pt2=(box[2], box[3]),
                    color=color_violet,
                    thickness=2,
                )

        return result_image

Functions

get_each_class_box staticmethod 

get_each_class_box(prediction: DetectionResult) -> tuple[list[BoundingBox], list[BoundingBox]]

Separates detection boxes into card boxes and patch boxes.

Parameters:

Name Type Description Default
prediction DetectionResult

The detection output that includes bounding boxes and class IDs.

 required

Returns:

Type Description
tuple[list[BoundingBox], list[BoundingBox]]

A tuple containing:

  • a list of card boxes (class id 1)
  • a list of patch boxes (class id 0).
Source code in color_correction/processor/detection.py 
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@staticmethod
def get_each_class_box(
    prediction: DetectionResult,
) -> tuple[list[BoundingBox], list[BoundingBox]]:
    """
    Separates detection boxes into card boxes and patch boxes.

    Parameters
    ----------
    prediction : DetectionResult
        The detection output that includes bounding boxes and class IDs.

    Returns
    -------
    tuple[list[BoundingBox], list[BoundingBox]]
        A tuple containing:

        - a list of card boxes (class id 1)
        - a list of patch boxes (class id 0).
    """
    ls_cards = [
        box
        for box, class_id in zip(
            prediction.boxes,
            prediction.class_ids,
            strict=False,
        )
        if class_id == 1
    ]
    ls_patches = [
        box
        for box, class_id in zip(
            prediction.boxes,
            prediction.class_ids,
            strict=False,
        )
        if class_id == 0
    ]
    return ls_cards, ls_patches

print_summary staticmethod 

print_summary(prediction: DetectionResult) -> None

Prints a summary of the detected cards and patches.

Parameters:

Name Type Description Default
prediction DetectionResult

The detection result to summarize.

 required
Source code in color_correction/processor/detection.py 
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@staticmethod
def print_summary(prediction: DetectionResult) -> None:
    """
    Prints a summary of the detected cards and patches.

    Parameters
    ----------
    prediction : DetectionResult
        The detection result to summarize.
    """
    ls_cards, ls_patches = DetectionProcessor.get_each_class_box(prediction)
    print(f"Number of cards detected: {len(ls_cards)}")
    print(f"Number of patches detected: {len(ls_patches)}")

process_patches staticmethod 

process_patches(input_image: ImageBGR, ordered_patches: list[tuple[BoundingBox, tuple[int, int]] | None]) -> tuple[list[ColorPatchType], ImageBGR]

Processes each detected patch by extracting its region from the image, computing its mean BGR color, and building a visualization grid.

Parameters:

Name Type Description Default
input_image ImageBGR

The original image containing detected patches.

 required
ordered_patches list[tuple[BoundingBox, tuple[int, int]] | None]

The list of ordered patch coordinates paired with their center points, possibly with missing entries as None.

 required

Returns:

Type Description
tuple[list[ColorPatchType], ImageBGR]

a tuple containing:

  • list of mean BGR color values for each patch.
  • an image visualizing these patches in a grid layout.
Source code in color_correction/processor/detection.py 
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@staticmethod
def process_patches(
    input_image: ImageBGR,
    ordered_patches: list[tuple[BoundingBox, tuple[int, int]] | None],
) -> tuple[list[ColorPatchType], ImageBGR]:
    """
    Processes each detected patch by extracting its region from the image,
    computing its mean BGR color, and building a visualization grid.

    Parameters
    ----------
    input_image : ImageBGR
        The original image containing detected patches.
    ordered_patches : list[tuple[BoundingBox, tuple[int, int]] | None]
        The list of ordered patch coordinates paired with their center
        points, possibly with missing entries as None.

    Returns
    -------
    tuple[list[ColorPatchType], ImageBGR]
        a tuple containing:

        - list of mean BGR color values for each patch.
        - an image visualizing these patches in a grid layout.
    """
    patch_size = (50, 50, 1)
    ls_bgr_mean_patch = []
    ls_horizontal_patch = []
    ls_vertical_patch = []

    for idx, coord_patch in enumerate(ordered_patches, start=1):
        if coord_patch is None:
            continue

        bbox_patch, _ = coord_patch

        # Extract and process each patch
        cropped_patch = crop_region_with_margin(
            image=input_image,
            coordinates=bbox_patch,
            margin_ratio=0.2,
        )
        bgr_mean_patch = calc_mean_color_patch(cropped_patch)
        ls_bgr_mean_patch.append(bgr_mean_patch)

        # Build visualization
        patch_viz = np.tile(bgr_mean_patch, patch_size)
        ls_horizontal_patch.append(patch_viz)
        if idx % 6 == 0:
            ls_vertical_patch.append(np.hstack(ls_horizontal_patch))
            ls_horizontal_patch = []

    patches_image = np.vstack(ls_vertical_patch)
    return ls_bgr_mean_patch, patches_image

extract_color_patches staticmethod 

extract_color_patches(input_image: ImageBGR, prediction: DetectionResult, draw_processed_image: bool = False) -> tuple[list[ColorPatchType], ImageBGR, ImageBGR | None]

Extracts and processes color patches from detected color checker cards, transforming the detection results with available methods.

The method first separates detected cards and patches, generates an expected patch grid, and then matches the detected patches with this grid. If patches are missing, it attempts to auto-fill them with suggested coordinates. Finally, it computes the mean color for each patch and builds a visualization.

Parameters:

Name Type Description Default
input_image ImageBGR

The original image containing the color checker card.

 required
prediction DetectionResult

The detection result output from the model.

 required
draw_processed_image bool

If True, returns an additional image with visualized detections. Otherwise, only patch processing is performed. Defaults to False.

 False

Returns:

Type Description
tuple[list[ColorPatchType], ImageBGR, ImageBGR | None]

a tuple containing:

  • a list of mean BGR color values for each patch.
  • an image visualizing these patches in a grid layout.
  • an optional image with visualized detection results.

Raises:

Type Description
ValueError

If no cards or patches are detected.
Source code in color_correction/processor/detection.py 
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@staticmethod
def extract_color_patches(
    input_image: ImageBGR,
    prediction: DetectionResult,
    draw_processed_image: bool = False,
) -> tuple[list[ColorPatchType], ImageBGR, ImageBGR | None]:
    """
    Extracts and processes color patches from detected color checker cards,
    transforming the detection results with available methods.

    The method first separates detected cards and patches, generates an expected
    patch grid, and then matches the detected patches with this grid. If patches
    are missing, it attempts to auto-fill them with suggested coordinates.
    Finally, it computes the mean color for each patch and builds a visualization.

    Parameters
    ----------
    input_image : ImageBGR
        The original image containing the color checker card.
    prediction : DetectionResult
        The detection result output from the model.
    draw_processed_image : bool, optional
        If True, returns an additional image with visualized detections.
        Otherwise, only patch processing is performed. Defaults to False.

    Returns
    -------
    tuple[list[ColorPatchType], ImageBGR, ImageBGR | None]
        a tuple containing:

        - a list of mean BGR color values for each patch.
        - an image visualizing these patches in a grid layout.
        - an optional image with visualized detection results.

    Raises
    ------
    ValueError
        If no cards or patches are detected.
    """
    ls_cards, ls_patches = DetectionProcessor.get_each_class_box(prediction)

    if not ls_cards:
        raise ValueError("No cards detected")
    if not ls_patches:
        raise ValueError("No patches detected")

    # Generate expected patch grid
    card_box = ls_cards[0]
    ls_grid_card = generate_expected_patches(card_box)

    # Match detected patches with grid
    ls_ordered_patch_bbox = extract_intersecting_patches(
        ls_patches=ls_patches,
        ls_grid_card=ls_grid_card,
    )

    # Handle missing patches
    d_suggest = None
    if None in ls_ordered_patch_bbox:
        print("Auto filling missing patches...")
        ls_ordered_bbox_only = [
            patch[0] if patch is not None else None
            for patch in ls_ordered_patch_bbox
        ]
        d_suggest = suggest_missing_patch_coordinates(ls_ordered_bbox_only)
        for idx, patch in d_suggest.items():
            cxpatch = (patch[0] + patch[2]) // 2
            cypatch = (patch[1] + patch[3]) // 2
            ls_ordered_patch_bbox[idx] = (patch, (cxpatch, cypatch))

    # Process patches and create visualizations
    ls_bgr_mean_patch, grid_patch_img = DetectionProcessor.process_patches(
        input_image=input_image,
        ordered_patches=ls_ordered_patch_bbox,
    )

    detection_viz = None
    if draw_processed_image:
        detection_viz = DetectionProcessor.draw_preprocess(
            image=input_image,
            expected_boxes=ls_grid_card,
            prediction=prediction,
            ls_ordered_patch_bbox=ls_ordered_patch_bbox,
            suggested_patches=d_suggest,
        )

    return ls_bgr_mean_patch, grid_patch_img, detection_viz

draw_preprocess staticmethod 

draw_preprocess(image: ImageBGR, expected_boxes: list[BoundingBox], prediction: DetectionResult, ls_ordered_patch_bbox: list[BoundingBox | None], suggested_patches: dict[int, BoundingBox] | None = None) -> ImageBGR

Draws visualizations on the input image to compare the detected patches with the expected positions. It overlays expected boxes, connects detected patches to their corresponding expected boxes, and highlights individual patch detections.

Parameters:

Name Type Description Default
image ImageBGR

The original image to draw on.

 required
expected_boxes list[BoundingBox]

List of expected bounding boxes for patches.

 required
prediction DetectionResult

The detection results containing predicted bounding boxes.

 required
ls_ordered_patch_bbox list[BoundingBox | None]

The list of ordered patch bounding boxes.

 required
suggested_patches dict[int, BoundingBox]

Dictionary of suggested patch coordinates for missing patches.

 None

Returns:

Type Description
ImageBGR

The image with drawn detection and patch visualizations.
Source code in color_correction/processor/detection.py 
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@staticmethod
def draw_preprocess(
    image: ImageBGR,
    expected_boxes: list[BoundingBox],
    prediction: DetectionResult,
    ls_ordered_patch_bbox: list[BoundingBox | None],
    suggested_patches: dict[int, BoundingBox] | None = None,
) -> ImageBGR:
    """
    Draws visualizations on the input image to compare the detected patches with
    the expected positions. It overlays expected boxes, connects detected patches to
    their corresponding expected boxes, and highlights individual patch detections.

    Parameters
    ----------
    image : ImageBGR
        The original image to draw on.
    expected_boxes : list[BoundingBox]
        List of expected bounding boxes for patches.
    prediction : DetectionResult
        The detection results containing predicted bounding boxes.
    ls_ordered_patch_bbox : list[BoundingBox | None]
        The list of ordered patch bounding boxes.
    suggested_patches : dict[int, BoundingBox], optional
        Dictionary of suggested patch coordinates for missing patches.

    Returns
    -------
    ImageBGR
        The image with drawn detection and patch visualizations.
    """
    color_green = (0, 255, 0)
    color_cyan = (255, 255, 10)
    color_violet = (255, 0, 255)
    color_red = (0, 0, 255)
    color_blue = (255, 0, 0)

    result_image = image.copy()

    # Draw all expected boxes
    for idx_b, box in enumerate(expected_boxes):
        cv2.rectangle(
            img=result_image,
            pt1=(box[0], box[1]),
            pt2=(box[2], box[3]),
            color=color_green,
            thickness=2,
        )

        # Draw connection lines between expected and detected patch boxes
        patch = ls_ordered_patch_bbox[idx_b]
        if patch is None:
            continue
        cx, cy = patch[1]
        crefx, crefy = (box[0] + box[2]) // 2, (box[1] + box[3]) // 2
        cv2.line(
            img=result_image,
            pt1=(cx, cy),
            pt2=(crefx, crefy),
            color=color_blue,
            thickness=1,
        )

    # Draw all predicted boxes
    for pbox, pids, pscore in zip(
        prediction.boxes,
        prediction.class_ids,
        prediction.scores,
        strict=False,
    ):
        if pids == 1:
            continue
        cv2.rectangle(
            img=result_image,
            pt1=(pbox[0], pbox[1]),
            pt2=(pbox[2], pbox[3]),
            color=color_cyan,
            thickness=2,
        )
        cv2.putText(
            img=result_image,
            text=f"{pids} {pscore:.2f}",
            org=(pbox[0] + 3, pbox[1] + 12),
            fontFace=cv2.FONT_HERSHEY_SIMPLEX,
            fontScale=0.4,
            color=color_red,
            thickness=1,
            lineType=cv2.LINE_AA,
        )

    # Draw suggested patches if provided
    if suggested_patches:
        for box in suggested_patches.values():
            cv2.rectangle(
                img=result_image,
                pt1=(box[0], box[1]),
                pt2=(box[2], box[3]),
                color=color_violet,
                thickness=2,
            )

    return result_image