Denoise (bilateral)

POST /api/image-denoise-traditional3 quota units per call · cache hits free

Denoise a photo with a bilateral filter — smooths flat regions while keeping edges sharp. Tune the colour and spatial sigmas to control how aggressive the smoothing is.

Runs OpenCV's bilateral filter — a denoiser that smooths flat areas while preserving edges. The trick is that two pixels only average together if they're both *close in space* AND *similar in colour*, so a sharp boundary between regions doesn't smear. Useful for: - Cleaning up low-light camera noise without blurring detail. - Pre-processing for OCR, contour detection, edge detection. - Stylising photos (heavy denoise gives a painted-look effect). `diameter` controls the filter's neighbourhood radius (higher = slower, more aggressive). `sigmaColor` controls how different two pixels' colours can be and still be averaged. `sigmaSpace` controls the spatial falloff. For most photos the defaults are a good starting point. ML-based denoisers (DnCNN, NAFNet) produce cleaner results on heavy noise — those will be added later as a `-ml` variant.

Inputs

Name	Type	Default	Description
image*	file	—	Input image bytes.
diameter	number (1…25)	9	Neighbourhood diameter in pixels. Higher = slower + more aggressive smoothing.
sigmaColor	number (1…250)	75	Colour-similarity sigma. Higher = pixels with more-different colours get averaged together.
sigmaSpace	number (1…250)	75	Spatial sigma. Higher = pixels further apart still influence each other.
format	enum (png \| jpeg)	"jpeg"	Output image format.

Response

Modes: binary, stream, json. Cache: yes (24h TTL).

Large outputs stream: responses over the 4 MiB cache limit are piped through as they are produced instead of buffered. They carry x-cache-skip: size and are never cached — identical follow-up calls recompute.

Every response carries x-cache (HIT / MISS / BYPASS), x-cache-signature (stable across identical inputs), and the rate-limit headers listed below.

Quota & limits

Cost per call	3 units against the 10,000-unit monthly quota. Cache hits are free — only cache misses decrement.
Burst limit	200 requests per rolling minute, shared across all tools.
Max request size	`25 MiB` (base64 inflates file payloads ~33% — the limit applies to the decoded bytes).
Max response size	`25 MiB`
Timeout	15s wall clock.
Rate-limit headers	`X-RateLimit-Limit`, `X-RateLimit-Remaining`, `X-RateLimit-Burst-Limit` on every response; `X-Quota-Warning` once 80% of the monthly quota is spent; `Retry-After` on 429s.

Errors

Errors are JSON with an error string; schema failures add a details object (Zod's flattened field errors).

Status	When	Body
400	Input fails the tool's schema (wrong type, missing required field, malformed base64) or the file bytes can't be parsed as the expected format.	{ "error": "invalid inputs", "details": { "fieldErrors": { … } } }
401	Missing or invalid X-Api-Key / X-Account-Id headers (or no session when called from the browser).	{ "error": "unauthorized" }
404	Unknown tool id, or calling /api/* on the website hostname instead of api.xtract.bot.	{ "error": "not found" }
413	Request body over the tool's max request size, or an image header declaring more megapixels than the tool's pixel budget.	{ "error": "…exceeds maxRequestBytes…" }
415	Content-Type isn't application/json on the json-body transport.	{ "error": "unsupported content-type; expected application/json" }
429	Monthly quota or the 200/min burst limit exhausted. Check Retry-After and the X-RateLimit-* headers.	{ "error": "monthly quota exceeded", "monthRemaining": 0, … }
5xx	Conversion engine failure. Safe to retry; if it persists, the input is hitting a bug — please report it.	{ "error": "…" }

Code samples

Built from the default example.

# Download or substitute the example input:
#   curl -O https://xtract.bot/examples/image-png-to-webp/sample.png
IMAGE=$(base64 -w0 < sample.png)

curl -X POST https://api.xtract.bot/api/image-denoise-traditional \
  -H "Content-Type: application/json" \
  -H "Accept: application/octet-stream" \
  -H "X-Account-Id: $XTRACT_ACCOUNT_ID" \
  -H "X-Api-Key: $XTRACT_API_KEY" \
  -d '{
  "diameter": 9,
  "sigmaColor": 75,
  "sigmaSpace": 75,
  "format": "jpeg",
  "image": "'"$IMAGE"'"
}'