camscanner-extract-formula

name	camscanner-extract-formula
description	Use CamScanner to extract formulas from images. Powered by OCR recognition engine that detects formula regions in images, crops them, and stitches into a single clean PNG image. Use when the user wants to extract mathematical formulas, equations, or expressions from images (photos, screenshots, scanned documents). Triggers on "extract formula", "get formulas from image", "crop formulas", "formula extraction", or when the user has an image containing math formulas and needs them extracted as a clean image.
metadata	{"author":"CamScanner","version":"1.0","openclaw":{"emoji":"🔢","requires":{"bins":["curl","jq"]}},"homepage":"https://www.camscanner.com"}

CamScanner Extract Formula

Overview

CamScanner provides formula extraction from images: OCR recognition detects formula regions, crops them, and vertically stitches all formulas into a single clean PNG image. The workflow is a 3-step pipeline: upload the image, extract formulas, then download the result.

When to Use

• User wants to extract mathematical formulas or equations from an image
• User has a photo, screenshot, or scanned document containing formulas
• User needs formulas cropped out as a clean image for further use
• User wants to isolate math content from surrounding text in an image

Privacy & Data

Important: Privacy & Data Flow Notice

• Third-party service: This skill sends your files to CamScanner's official servers (ai-tools.camscanner.com) for processing.
• Data retention: CamScanner servers process your files in real-time. Files are not permanently stored on the server.
• Local files: Output files are saved to your local filesystem at the path you specify.

API Reference

Base URL: https://ai-tools.camscanner.com

Supported Modes

extract_mode	Description	Output
formula	Extract math formulas, crop and stitch into one image	.png

Step 1: Upload Image

BASE="https://ai-tools.camscanner.com"

IN_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/upload_file/execute" \
  -H "Content-Type: application/octet-stream" \
  --data-binary "@/path/to/image.png" | jq -r '.tool_result.data.file_id')

Response:

{
  "code": 200,
  "tool": "upload_file",
  "tool_result": {
    "success": true,
    "data": {
      "file_id": "file_1741857600_ab12cd34ef56",
      "size": 24576
    }
  }
}

Step 2: Extract Formulas

OUT_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/extract_image/execute" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$IN_FILE_ID\",\"extract_mode\":\"formula\"}" \
  | jq -r '.tool_result.data.file_id')

Response:

{
  "code": 200,
  "tool": "extract_image",
  "tool_result": {
    "success": true,
    "data": {
      "file_id": "file_1741857701_9988aabbccdd",
      "target_type": ""
    },
    "metadata": {
      "engine": "extractformula",
      "formula_count": 6
    }
  }
}

Step 3: Download Result

curl -sS -X POST "$BASE/v1/tools/download_file/execute?response_mode=raw" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$OUT_FILE_ID\"}" \
  -o /path/to/formulas.png

Critical: The response_mode=raw query parameter is required to get the binary file. Without it, the response is JSON.

Quick Reference: Complete Pipeline

BASE="https://ai-tools.camscanner.com"
INPUT_IMAGE="/path/to/image.png"
OUTPUT_FILE="/path/to/formulas.png"

# Upload
IN_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/upload_file/execute" \
  -H "Content-Type: application/octet-stream" \
  --data-binary "@$INPUT_IMAGE" | jq -r '.tool_result.data.file_id')

# Extract
OUT_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/extract_image/execute" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$IN_FILE_ID\",\"extract_mode\":\"formula\"}" \
  | jq -r '.tool_result.data.file_id')

# Download
curl -sS -X POST "$BASE/v1/tools/download_file/execute?response_mode=raw" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$OUT_FILE_ID\"}" \
  -o "$OUTPUT_FILE"

Common Mistakes

Mistake	Fix
Forgetting response_mode=raw on download	Always append ?response_mode=raw to the download URL
Wrong Content-Type on upload	Upload uses application/octet-stream, not multipart/form-data
Using GET instead of POST	All three endpoints use POST
Missing extract_mode in extract request	Always include "extract_mode": "formula"
Saving output with wrong extension	Output is always PNG format — use .png extension

Error Handling

Check each step before proceeding:

# After upload
if [ -z "$IN_FILE_ID" ] || [ "$IN_FILE_ID" = "null" ]; then
  echo "Upload failed"; exit 1
fi

# After extract
if [ -z "$OUT_FILE_ID" ] || [ "$OUT_FILE_ID" = "null" ]; then
  echo "Extraction failed"; exit 1
fi