Image Upscaling

AI super-resolution enhancement using Real-ESRGAN. Upscales images 2x-4x while preserving detail.

API Endpoint

POST /api/v1/tools/upscale

Processing: Asynchronous (returns 202, poll /api/v1/jobs/{jobId}/progress for status via SSE)

Model bundle: upscale-enhance (4-5 GB)

Parameters

Parameter	Type	Required	Default	Description
file	file	Yes	-	Image file (multipart)
scale	number	No	2	Upscale factor (e.g., 2, 3, 4)
model	string	No	"auto"	Model to use (e.g., auto, specific model names)
faceEnhance	boolean	No	false	Apply face enhancement during upscaling
denoise	number	No	0	Denoising strength (0 = off)
format	string	No	"auto"	Output format: auto, png, jpg, webp, tiff, gif, avif, heic, heif, jxl
quality	number	No	95	Output quality (1-100)

Example Request

curl -X POST http://localhost:13490/api/v1/tools/upscale \
  -F "[email protected]" \
  -F 'settings={"scale":4,"model":"auto","faceEnhance":true,"format":"png"}'

Response

Initial Response (202 Accepted)

{
  "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "async": true
}

Progress (SSE at /api/v1/jobs/{jobId}/progress)

event: progress
data: {"phase":"processing","stage":"Upscaling...","percent":60}

Final Result (via SSE)

{
  "phase": "complete",
  "percent": 100,
  "result": {
    "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    "downloadUrl": "/api/v1/download/{jobId}/photo_4x.png",
    "previewUrl": "/api/v1/download/{jobId}/preview.webp",
    "originalSize": 120000,
    "processedSize": 2400000,
    "width": 4096,
    "height": 4096,
    "method": "realesrgan-x4plus"
  }
}

Notes

• Requires the upscale-enhance model bundle to be installed (4-5 GB).
• Uses Real-ESRGAN when available; falls back to Lanczos interpolation if the AI model is unavailable.
• The faceEnhance option applies GFPGAN face restoration during upscaling for better face quality.
• For non-browser-previewable output formats (HEIC, JXL, TIFF), a WebP preview is generated alongside the main output.
• Supports HEIC/HEIF, RAW, TGA, PSD, EXR, and HDR input formats via automatic decoding.