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