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#

source_typeenhance_modeOperationOutputimage9Erase handwriting.jpg

Step 1: Upload Image#

bash

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:

json

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

Step 2: Enhance Image (Erase Handwriting)#

bash

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:

json

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

Step 3: Download Result#

bash

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:

bash

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):

bash

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):

bash

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#

MistakeFixForgetting response_mode=raw on downloadAlways append ?response_mode=raw to the download URLWrong Content-Type on uploadUpload uses application/octet-stream, not multipart/form-dataUsing GET instead of POSTAll endpoints use POSTPassing enhance_mode as a stringenhance_mode is an integer — use 9, not "9"Missing output_mode in enhance requestMust be either "file_id" (then download separately) or "raw" (stream out)Parsing JSON when output_mode is "raw"With raw, the response body IS the image — write it to a file with -oTrying to download a file_id after raw responseraw mode returns no file_id; re-run in file_id mode if you need one

Error Handling#

Check each step before proceeding:

bash

# 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