.. _changelog_v1_9_0:

v1.9.0
======

v1.9.0 adds the **Canny edge detector**, a **Hough transform** line detector,
an ``image.gaussian()`` filter, ``image.mask_ellipse()``, FREAK-keypoint
k-means clustering, and a face-recognition (LBP) example. It introduces **no
breaking API changes** — v1.8.0 scripts run unchanged.

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Highlights
----------

- **Canny edge detector** — ``image.find_edges()``.
- **Hough transform** — line detection (with an example).
- ``image.gaussian()`` filter and ``image.mask_ellipse()``.
- **FREAK k-means** — cluster FREAK keypoints with k-means.
- **No breaking API changes** — reflash and your v1.8.0 scripts run
  unchanged.

New features
------------

- Added the Canny edge detector (and a simple edge function), the Hough
  transform line detector with a Hough-transform example, an
  ``image.gaussian()`` filter, ``image.mask_ellipse()``, FREAK-keypoint
  k-means clustering, and a face-recognition (LBP) example.

Other changes and improvements
------------------------------

- Updated the face detector's default thresholds; ``histeq()`` now returns
  the argument image (chainable); initialize the RNG when ``randint()`` is
  called.

Bug fixes
---------

- Fixed LBP for face recognition and applied several Canny edge-detector
  fixes.

Breaking API changes
--------------------

v1.9.0 introduces **no breaking Python API changes**. Scripts that ran on
v1.8.0 run unchanged on v1.9.0 — just reflash the firmware. (Note: the
built-in face detector's default thresholds were tuned; re-check face
detection if you relied on the previous defaults.)