v2.1.0

v2.1.0 is a massive API-modernization release. It replaces the FREAK keypoint descriptor with ORB, reworks find_blobs() / histograms / statistics into object-based APIs, renames the sensor auto exposure/gain/white- balance functions, adds QR-code detection and OV7725 lens correction, and brings up the initial OpenMV Cam M7 board. Many APIs changed — read the breaking changes below.

Highlights

  • ORB keypoints — the FREAK descriptor was replaced with ORB (find_keypoints() / match_descriptor() reworked).

  • Object APIs — find_blobs(), get_histogram(), get_statistics() now return objects with named accessors.

  • QR codes — image.find_qrcodes() detection added.

  • OpenMV Cam M7 — initial board support.

  • Sensor — set_auto_whitebal() / set_auto_gain() / set_auto_exposure() (renamed) and set_lens_correction().

  • Breaking: the keypoint/descriptor, blob/histogram/statistics, sensor auto-function, and several other APIs changed — see the breaking changes.

New features

  • OpenMV Cam M7 — added initial OpenMV 3 (M7) board support.

  • QR codes — added image.find_qrcodes() with a qrcodes.py example.

  • ORB keypoints — new ORB descriptor system: find_keypoints() with a corner_detector argument (CORNER_FAST / CORNER_AGAST), max_keypoints / scale_factor; match_descriptor() with a filter_outliers keyword and a rotation estimate; keypoint save/load.

  • Object APIs — image.get_histogram() / get_statistics() / get_percentile() return histogram/statistics objects; find_blobs() returns blob objects (rect() / cx() / cy() / code() / area() / pixels()) with area_threshold / pixels_threshold / merge / margin / invert and x_stride / y_stride.

  • Sensor — added sensor.set_lens_correction(enable, radi, coef) for OV7725 lens shading, sensor.set_windowing() now also accepts a (w, h) tuple (auto-centered), and image.Image(..., copy_to_fb=True) / load_image(copy_to_fb=True).

  • Added color-tracking, Arduino SPI/I2C-slave, keypoints, and histogram/statistics example scripts.

Other changes and improvements

  • The IDE can now interrupt a running main.py; faster find_blobs() / find_qrcodes() / get_statistics(); ORB uses a popcount Hamming distance; lens correction uses less RAM; a Linux udev rule stops ModemManager from grabbing the serial port.

Bug fixes

Camera and imaging:

  • Fixed M7 DMA cache clean/invalidate (corrupted frames), a spurious extra line at the end of each frame, JPEG framebuffer overflow bounds, freeing the framebuffer on compress() failure, ORB accuracy / ROI / empty-set handling, and load_image(copy_to_fb=True) geometry.

System:

  • Fixed F7 ADC support, an OV7725 register name, bootloader/USB timing, used WFI while waiting for snapshots, and made the MJPEG streamer example non-blocking with per-client timeouts.

Hardware and board support

  • OpenMV Cam M7 (OpenMV 3) — initial board support.

  • OV7725 — lens-correction (shading) support.

Breaking API changes

User-visible API breaks between v2.0.0 and v2.1.0. Scope: Python C-modules in modules/ and Python libraries in scripts/libraries/.

Each change is tagged with its impact:

  • major — affects most scripts that used the feature; you will need to port code.

  • minor — narrow API; only affects scripts that used it.

  • behavior — same API, different results; re-check tuned scripts.

Changes are grouped by impact in that order. If you just want to port your code, jump to the migration checklist at the end. Each commit hash links to its diff on GitHub.

FREAK replaced with ORB; descriptor API reworked (major)

The FREAK keypoint descriptor was removed and replaced with ORB: image.FREAK no longer exists (use image.ORB). image.match_descriptor() / save_descriptor() / load_descriptor() no longer take a leading descriptor-type argument (it is inferred from the object), match_descriptor() now returns an 8-element tuple (cx, cy, x, y, w, h, match_count, rotation) (the last element is a raw count, not a percentage), and draw_keypoints() requires a keypoints object instead of a raw (x, y, angle) list. find_keypoints() gained corner_detector / max_keypoints / scale_factor with changed defaults.

Commits: e2d0c4840, bba8e5a9e, 6000684cb

Sensor auto-function rename (major)

sensor.set_whitebal() / set_gain_ctrl() / set_exposure_ctrl() were renamed to sensor.set_auto_whitebal() / set_auto_gain() / set_auto_exposure() (the old names were removed). Each gained an optional value= keyword to set a manual value instead of auto.

Commits: 1b22a2961

Histogram / statistics reworked to object APIs (major)

The histogram/statistics surface was reworked into object-based image.get_histogram() / get_statistics() / get_percentile() returning histogram/statistics objects. The old flat histogram/statistics results and the bin_count / l_bin_count / a_bin_count / b_bin_count methods were removed (use len(histogram.bins()) etc.).

Commits: 011108412, 9f37c83de

find_features() scale renamed (major)

image.find_features() (Haar) renamed its scale= keyword to scale_factor=. Update find_features(cascade, scale=...) calls to scale_factor=....

Commits: 96e4f770c

find_blobs() returns objects; find_markers() removed (minor)

image.find_blobs() now returns blob objects with named accessors (index access still works for backward compatibility), and image.find_markers() was removed — use find_blobs(..., merge=True, margin=...) instead. The advanced color-blob filter callback is no longer supported.

Commits: af15ec6eb

img.copy_to_fb() replaced (minor)

The img.copy_to_fb() method was replaced by a copy_to_fb= keyword on image.Image / load_image(). Use image.Image(path, copy_to_fb=True) to load large images straight into the framebuffer.

Commits: 1645ab94b

compress() rejects out-of-range quality (behavior)

image.compress() / compressed() now raise an error when quality is outside 1–100 instead of silently clamping. Clamp quality into 1–100 before calling. Separately, the OpenMV 3 JPEG buffer was reduced from 64 KB to 23000 bytes, so large frames may now raise out-of-memory — lower the JPEG quality or framesize.

Commits: 9efd7474a, 9a7c3defc

lens_corr() zoom is now functional (behavior)

image.lens_corr() now actually applies its zoom argument (it was previously parsed but ineffective), so output differs for scripts that passed a non-default zoom. Re-check lens_corr() tuning.

Commits: d6b49adef

Migration checklist

For a clean port to v2.1.0 the typical work is:

  1. Replace image.FREAK with image.ORB, drop the descriptor-type argument, and update match_descriptor() tuple unpacking / draw_keypoints() to the keypoints object (the ORB rework).

  2. Rename sensor.set_whitebal() / set_gain_ctrl() / set_exposure_ctrl() to the set_auto_* forms (the auto-function rename).

  3. Move histogram/statistics code to the object methods (the histogram/statistics rework).

  4. Rename find_features() scale= to scale_factor= (the find_features rename).

  5. Use blob-object accessors and replace find_markers() with find_blobs(merge=True, ...) (the find_blobs change); replace img.copy_to_fb() with the copy_to_fb= keyword (the copy_to_fb change).

  6. Clamp compress() quality to 1–100 and re-check JPEG sizes on the OpenMV 3 (the compress change); re-tune lens_corr() zoom (the lens_corr change).

All other scripts run unchanged.