AgentSkillsCN

extract-pdf-figure

借助Qwen3-VL视觉模型，通过精确的边界框检测，从学术PDF论文中提取图表与表格。支持完整图表的提取（含标题、图例、注释），或仅提取主内容。还可提取子图，例如图1(a)。当用户要求从PDF论文中提取、裁剪或获取图表/表格时，可使用此功能。

SKILL.md
--- frontmatter
name: extract-pdf-figure
description: Extract figures and tables from academic PDF papers with precise bounding box detection using Qwen3-VL vision model. Supports extracting complete figures (with title, legend, notes) or main content only. Can extract sub-figures like Figure 1(a). Use when user asks to extract, crop, or get figures/tables from PDF papers.
argument-hint: <pdf_path> <figure_name> [--no-extras]
allowed-tools: Bash(python *), Bash(conda *)

PDF Figure & Table Extraction Skill

Extract figures and tables from academic PDF papers with pixel-perfect precision using the Qwen3-VL vision-language model. Features multi-round quality assessment for optimal extraction accuracy.

Quick Start

bash
# Extract a complete figure (including title, legend, notes)
python .claude/skills/extract-pdf-figure/scripts/extract_figures.py "<pdf_path>" "<figure_name>"

# Extract main content only (no title, legend, notes)
python .claude/skills/extract-pdf-figure/scripts/extract_figures.py "<pdf_path>" "<figure_name>" --no-extras

# Batch extraction with output directory
python .claude/skills/extract-pdf-figure/scripts/extract_figures.py "<pdf_path>" --batch "Figure 1,Figure 2,Table 1" -d "output/asset/"

Features

1. Extraction Modes

ModeFlagDescription
Complete(default)Includes figure number, caption, legend, notes, and main content
Content Only--no-extrasOnly the chart/diagram/table data, without surrounding text

2. Multi-Round Quality Assessment

The tool uses an iterative refinement process:

  1. •Round 1: Initial figure detection and bounding box estimation
  2. •Round 2+: Quality assessment with visual feedback (red bounding box overlay)
  3. •Refinement: If quality score < 8/10, coordinates are automatically adjusted
  4. •Termination: Stops when quality is satisfactory or max rounds reached (default: 3)

3. Supported Figure Types

  • •Figure 1, Figure 2, etc.
  • •Table 1, Table 2, etc.
  • •Fig. 1, Fig 1 (abbreviated)
  • •Figure 1(a), Figure 1 (a), Figure 1a (sub-figures)
  • •Table 1(a) (sub-tables)

Usage Examples

Single Figure Extraction

bash
# Complete figure with all elements
python .claude/skills/extract-pdf-figure/scripts/extract_figures.py "PDFs/paper.pdf" "Figure 1"

# Only the chart content (no caption)
python .claude/skills/extract-pdf-figure/scripts/extract_figures.py "PDFs/paper.pdf" "Figure 1" --no-extras

# With custom output path
python .claude/skills/extract-pdf-figure/scripts/extract_figures.py "PDFs/paper.pdf" "Table 2" -o "output/asset/Table_2.png"

# Higher resolution
python .claude/skills/extract-pdf-figure/scripts/extract_figures.py "PDFs/paper.pdf" "Figure 3" --dpi 400

Sub-Figure Extraction

bash
# Extract only Figure 1(a) from a composite figure
python .claude/skills/extract-pdf-figure/scripts/extract_figures.py "PDFs/paper.pdf" "Figure 1(a)"

# Sub-figure with custom output
python .claude/skills/extract-pdf-figure/scripts/extract_figures.py "PDFs/paper.pdf" "Figure 2(b)" -o "output/asset/Figure_2b.png"

Batch Extraction

bash
# Extract multiple figures/tables at once
python .claude/skills/extract-pdf-figure/scripts/extract_figures.py "PDFs/paper.pdf" --batch "Figure 1,Figure 2,Figure 3,Table 1,Table 2" -d "output/asset/"

# Batch without extras
python .claude/skills/extract-pdf-figure/scripts/extract_figures.py "PDFs/paper.pdf" --batch "Figure 1,Figure 2" --no-extras -d "output/asset/"

Command Line Options

OptionShortDescription
pdf_pathPDF file path (required)
figure_nameFigure/Table name (required for single extraction)
--output-oOutput image path
--dpiRendering resolution (default: 300)
--batch-bComma-separated figure names for batch extraction
--output-dir-dOutput directory for batch extraction
--no-extrasExclude title, legend, notes (extract main content only)
--max-roundsMax quality refinement rounds (default: 3)

Output

  • •Format: PNG images
  • •Default location: extracted_figures/ directory next to the PDF
  • •Naming: <pdf_name>_<figure_name>.png

Dependencies

依赖已在项目 requirements.txt 中定义，安装方法请参考 README.md。

主要依赖：

  • •PyMuPDF - PDF 解析
  • •Pillow - 图像处理
  • •openai - API 客户端
  • •python-dotenv - 环境变量加载

How It Works

  1. •PDF to Image: Each PDF page is rendered at high resolution (300 DPI default)
  2. •AI Detection: Qwen3-VL model locates the target figure and returns bounding box coordinates
  3. •Quality Check: The extraction is visually assessed; if needed, coordinates are refined
  4. •Precise Cropping: The image is cropped with minimal padding to capture the exact figure
  5. •Output: Saved as an optimized PNG file

Tips for Best Results

  1. •Figure Names: Use exact names as they appear in the paper (e.g., "Figure 1", not "fig 1")
  2. •Composite Figures:
    • •Use "Figure 1" to get all sub-figures with the main caption
    • •Use "Figure 1(a)" to get only that specific sub-figure
  3. •Tables: Caption is typically above, so the tool searches upward
  4. •Quality: Use --dpi 400 for very detailed figures
  5. •Content Only: Use --no-extras when you only need the visual data without surrounding text

Additional Resources