Introduction

Main widget

The main widget is structured in several groups:

Napari-Correct-Drift's main widget

The five groups are:

  1. Input Axes

  2. Correct Drift

  3. Key Frames

  4. Parameters

  5. Outliers

Input Axes

Select the Napari layer to process using the drop-down element. Once the layer is selected, make sure the dimensions are correctly set.

When using multidimensional images (with more than 3 dimensions), Napari-Correct-Drift needs to know which dimension corresponds to the Z, Channel and Time dimension. The Time dimension always needs to be assigned.

Use the drop-down elements per Axis to set Z, Channel and Time. Napari-Correct-Drift displays the size of the selected dimension in brackets.

Correct Drift

Run Napari-Correct-Drift using the set parameters. One can Estimate Drift or Load Drift from a .csv file. Both options will open the Napari-Correct-Drift Table Widget. The table contains the Z,Y,X drifts per time frame.

Select Correct Drift to apply the drifts from the table widget to your image data. A new image layer containing the corrected image will be created.

One can follow the progress of the estimation and the correction step in the Napari notifications panel.

Key Frames

  • Relative to: Choose previous frame to estimate drift on consecutive frames or absolute frame when using an absolute reference frame:

    Mode for drift estimation:

    1. previous frame: estimate from previous frame. (ROI will move along!)

    2. absolute frame: estimate against absolute frame

  • Key frame: The frame index to use. Note, when computing the drifts relative to previous frame, the key frame will be the frame with zero drifts applied. When Use ROI is enabled, the value is inferred from the ROI.

  • Key channel: Channel index to use for the drift computation. When Use ROI is enabled, the value is inferred from the ROI.

  • Use ROI: When enabled Napari-Correct-Drift expects an ROI in a shape layer named ROI. If such a layer is not yet present, it will be automatically created. Add an ROI (e. g. Rectangle shape) at desired channel and key frame.

  • ROI z-min and ROI z-max: Minimum and maximum z-slice indecies for 3D-bounding box

Parameters

  • Increment Frame increment step for drift estimation. Useful for faster processing and slow drifts. Skipped frames will be linearly interpolated.

  • Upsample factor Subpixel accurate drift estimation. Images will be registered to within 1 / upsample_factor of a pixel. Useful for slow drifts.

  • Extend output Correct drifts with extended spatial dimensions. The raw image frames will be fully contained in the output

  • Use phase normalization Phase normalization (recommended) works well in registering images under different illumination . In a high noise scenario, the un-normalized method may be preferable.

Outliers

  • Remove & Interpolate Remove large shifts in consecutive time frames (in mode previous frame) and linearly interpolate from other time points.

  • Max shift Z,Y,Z Maximum relative shift allowed in X,Y, or Z. If estimated shift exceeds set value the exceeding shift is removed and linearly interpolated (in pixel).

Table Widget

The Table Widget will display a table of estimated or loaded drifts. It contains 4 columns: frame, Z, Y, X. For 2D images Z will always contain 0.

Note, the displayed drifts can be edited by clicking into a cell.

  • Copy to clipboard Copy the drift table to your system clipboard

  • Save as csv Create a comma separated value file (.csv) containing the drift values.