creative-graphic-design/layout-average-iou

Layout Average IoU

Description

The Layout Average IoU metric computes the average Intersection over Union (IoU) for all pairs of overlapping elements in a layout. This metric evaluates how efficiently elements are arranged by measuring the degree of overlap between layout components.

What It Measures

This metric implements two variants of average IoU that have been used in different layout generation research:

1. 1.VTN (Variational Transformer Networks): Standard geometric IoU calculation
2. 2.BLT (Bidirectional Layout Transformer): Perceptual IoU that considers the global union area on a discrete grid

Lower values generally indicate better layouts with less overlap between elements.

Metric Details

• —Computes IoU for all pairs of elements in a layout (excluding diagonal comparisons where elements would overlap with themselves)
• —Only considers pairs with IoU > 0 (actual overlap)
• —Returns the mean IoU across all overlapping pairs
• —Returns 0.0 for layouts with 0 or 1 elements (no overlap possible)

Usage

Installation

pip install evaluate

Basic Example

import evaluate
import numpy as np

# Load the metric
metric = evaluate.load("creative-graphic-design/layout-average-iou")

# Single layout processing
num_samples, num_coordinates = 24, 4
layout = {
    "bboxes": np.random.rand(num_samples, num_coordinates),
    "categories": np.random.randint(0, num_coordinates, size=(num_samples,)),
}
metric.add(layouts=layout)
print(metric.compute())

Batch Processing Example

import evaluate
import numpy as np

# Load the metric
metric = evaluate.load("creative-graphic-design/layout-average-iou")

# Batch processing
batch_size, num_samples, num_coordinates = 512, 24, 4
layouts = [
    {
        "bboxes": np.random.rand(num_samples, num_coordinates),
        "categories": np.random.randint(0, num_coordinates, size=(num_samples,)),
    }
    for _ in range(batch_size)
]
metric.add_batch(layouts=layouts)
print(metric.compute())

Parameters

Initialization Parameters

This metric does not require any initialization parameters.

Computation Parameters

• —layouts (list of dict): A list of dictionaries representing layouts, where each dictionary contains:
• —bboxes (list of float): Bounding boxes in center-x, center-y, width, height (xywh) format
• —categories (list of int): Category labels for each element

Returns

Returns a dictionary containing:

• —average-iou_BLT (float): Average IoU using the perceptual IoU method from BLT
• —average-iou_VTN (float): Average IoU using standard geometric IoU from VTN

Interpretation

• —Lower values indicate better layouts with less element overlap
• —Value of 0.0: No overlapping elements (ideal for most layout types)
• —Higher values: More overlap between elements, potentially indicating layout quality issues
• —Typical range: 0.0 to 1.0

The two variants (BLT and VTN) may produce slightly different values due to their different calculation methods:

• —VTN uses standard geometric IoU
• —BLT uses perceptual IoU with discrete grid quantization (32x32)

Citations

@inproceedings{arroyo2021variational,
  title={Variational transformer networks for layout generation},
  author={Arroyo, Diego Martin and Postels, Janis and Tombari, Federico},
  booktitle={Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition},
  pages={13642--13652},
  year={2021}
}

@inproceedings{kong2022blt,
  title={BLT: bidirectional layout transformer for controllable layout generation},
  author={Kong, Xiang and Jiang, Lu and Chang, Huiwen and Zhang, Han and Hao, Yuan and Gong, Haifeng and Essa, Irfan},
  booktitle={European Conference on Computer Vision},
  pages={474--490},
  year={2022},
  organization={Springer}
}

References

• —Paper: Variational Transformer Networks for Layout Generation (Arroyo et al., CVPR 2021)
• —Paper: BLT: Bidirectional Layout Transformer for Controllable Layout Generation (Kong et al., ECCV 2022)
• —Reference Implementation: layout-dm metric implementation
• —Hugging Face Space: creative-graphic-design/layout-average-iou

Related Metrics

• —Layout Maximum IoU: Measures maximum IoU between two layout sets
• —Layout Overlap: Alternative overlap metrics from various research works
• —Layout Alignment: Measures spatial alignment of layout elements