Install
openclaw skills install @camscanner-ai/camscanner-extract-formulaUse 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.
openclaw skills install @camscanner-ai/camscanner-extract-formulaCamScanner 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.
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.
Base URL: https://ai-tools.camscanner.com
| extract_mode | Description | Output |
|---|---|---|
| formula | Extract math formulas, crop and stitch into one image | .png |
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
}
}
}
OUT_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/extract_image/execute" \
-H "Content-Type: application/json" \
-d "{\"file_id\":\"$IN_FILE_ID\",\"extract_mode\":\"formula\"}" \
| jq -r '.tool_result.data.file_id')
Response:
{
"code": 200,
"tool": "extract_image",
"tool_result": {
"success": true,
"data": {
"file_id": "file_1741857701_9988aabbccdd",
"target_type": ""
},
"metadata": {
"engine": "extractformula",
"formula_count": 6
}
}
}
curl -sS -X POST "$BASE/v1/tools/download_file/execute?response_mode=raw" \
-H "Content-Type: application/json" \
-d "{\"file_id\":\"$OUT_FILE_ID\"}" \
-o /path/to/formulas.png
Critical: The response_mode=raw query parameter is required to get the binary file. Without it, the response is JSON.
BASE="https://ai-tools.camscanner.com"
INPUT_IMAGE="/path/to/image.png"
OUTPUT_FILE="/path/to/formulas.png"
# Upload
IN_FILE_ID=$(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"
| 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 |
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