CamScanner Image Erase Handwriting

Overview

CamScanner provides a high-precision image enhancement engine that removes handwriting from images while preserving the printed content and original layout. It intelligently detects handwritten strokes, annotations, and signatures and erases them, leaving the underlying document clean and legible. The workflow is a 3-step pipeline: upload the image, enhance it with enhance_mode: 9 (erase handwriting), then download the result. For convenience, the enhance step also supports a raw output mode that returns the processed image bytes directly, skipping the download step.

When to Use

• User wants to remove handwriting, annotations, or signatures from an image
• User has a scan or photo of a document with handwritten notes that need to be cleaned
• User wants to restore a blank form after it was filled in by hand
• User has an annotated scan and needs a clean copy for OCR, printing, or sharing

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 Enhancements

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.jpg" | 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: Enhance Image (Erase Handwriting)

OUT_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/enhance_image/execute" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$IN_FILE_ID\",\"enhance_mode\":9,\"output_mode\":\"file_id\"}" \
  | jq -r '.tool_result.data.file_id')

Response:

{
  "code": 200,
  "tool": "enhance_image",
  "tool_result": {
    "success": true,
    "data": {
      "file_id": "file_1741857701_9988aabbccdd",
      "enhance_mode": 9
    }
  }
}

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/output.jpg

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

Alternative: One-Shot Raw Output

If you don't need a reusable file_id for the result, pass "output_mode": "raw" to enhance_image and save the response body directly — this combines steps 2 and 3:

curl -sS -X POST "$BASE/v1/tools/enhance_image/execute" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$IN_FILE_ID\",\"enhance_mode\":9,\"output_mode\":\"raw\"}" \
  -o /path/to/output.jpg

Quick Reference: Complete Pipeline

Erase handwriting from an image (three-step, keeps an output file_id):

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

# 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')

# Enhance (erase handwriting)
OUT_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/enhance_image/execute" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$IN_FILE_ID\",\"enhance_mode\":9,\"output_mode\":\"file_id\"}" \
  | 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"

Or one-shot (two-step, raw image stream straight from enhance_image):

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

# 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')

# Enhance + download in one call
curl -sS -X POST "$BASE/v1/tools/enhance_image/execute" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$IN_FILE_ID\",\"enhance_mode\":9,\"output_mode\":\"raw\"}" \
  -o "$OUTPUT_FILE"

Common Mistakes

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 enhance (file_id mode)
if [ -z "$OUT_FILE_ID" ] || [ "$OUT_FILE_ID" = "null" ]; then
  echo "Enhancement failed"; exit 1
fi