Image Stitching Tutorial
This image stitching tutorial provides step-by-step instructions for loading image data in the Stitching workspace (see Loading the Image Stitching Tutorial Dataset) and then automatically aligning image tiles in an image grid and stitching the result into a single high-resolution image (see Using the Automated Stitching Methods). Directions for manually manipulating image tiles in the Stitching workspace are also available (see Using the Value Stitcher and Move Tools).
Detail of the original dataset (left) and stitching result (right)
Loading the Image Stitching Tutorial Dataset
- Download and unzip the image stitching tutorial dataset — Tongue Tissue Section.
The dataset is available on the ORS website at: http://www.theobjects.com/dragonfly/learn-sample-datasets.html.
- Load the tutorial dataset you downloaded with the Image Loader (see Importing Image Files).
- Right-click the tutorial dataset in the Data Properties and Settings panel and then choose Dataset Stitching in the pop-up menu.
The Layout Editor appears in the Stitching contextual window.
- Choose the following settings for each available parameter on the Grid Layout tab.
Parameter
Setting
Slices
1
Rows
3
Columns
5
Tile Overlap (10%)
5
Grid Layout
Row-by-row / Right / Down
- Click the Apply Layout button.
The tiled images appear in the Stitching workspace.
- Continue to the next sections to learn how to stitch the tiled images in the Stitching workspace.
Using the Automated Stitching Methods
- Load the image stitching tutorial dataset and apply the required image grid (see Loading the Image Stitching Tutorial Dataset).
- Select the Highlight channels option in the Blend box at the bottom of the Stitcher panel.
This will let you see the border of each image tile in the Stitcher workspace.
- Zoom in on the top two image tiles on the top left corner of the mosaic with the Zoom
tool on the Manipulate panel. - Click the Select (Reference)
button in the Actions box and then click the leftmost image tile at the top of the mosaic. - Click the Select (To Stitch)
button in the Actions box and then click the image tile to the right of the one you selected previously.
- Choose the following settings in the Stitching box:
Setting
Method
Template Matching (translation)
Template matching method
Square Difference
Application
Pairwise
Min Overlap (%)
1
Current Selection
Selected
- Click the Preview Template Matching button to see the results of the template matching method.
NOTE See Template Matching to learn about the template matching method.
- Close the Preview window.
- Click the Stitch button.
The "To Stitch" image tile is translated so that the overlapping area is precisely aligned with the "Reference" image tile, as shown below.
- Make sure that the Select (Reference) option is selected in the Actions box and then click the Select All
button.
All of the image tiles in the mosaic are highlighted in red.
- Keep the same settings you selected previously for the Template Matching method, except change the Application to Grid.
- Click the Stitch button.
The correct overlaps for all tiles in the image grid are calculated and the required geometric transformations are applied to all image tiles in the mosaic.
- Click inside the Name field in the Output box and then rename the output "stitching-result".
- Make sure that Channel is selected as the output and then click the Save button.
NOTE You can also save a configuration file as the output for a stitching operation (see Output Options).
- Click OK to close the information box.
The stitching result is saved as new dataset in the shape of the stitched image tiles and is available in the Data Properties and Settings panel.
- Click the Edit Layout button at the top of the Stitcher panel.
The Layout Editor appears in the workspace.
- Make sure that the layout options are the same as when you originally loaded the dataset and then click the Apply Layout button to reset the image grid.
- Select the fourth image tile in the second row as the "Reference" selection and then the adjacent tile to the left as the "To Stitch" selection.
- Choose the following settings in the Stitching box:
Setting
Method
Feature Base
Template Detector
ORB
Motion
Translation (selected)
Rotation (not selected)Epsilon
-1
Number of Iterations
1000
Number of Features
45
Application
Pairwise
Min Overlap (%)
1
Current Selection
Selected
- Click the Preview Feature button to see the results of the feature base matching method.
Note how the features from the "Reference" selection are mapping to the features on the "To Stitch" selection in the Preview window.
NOTE See Feature Base to learn more about the feature base matching method.
- Close the Preview window.
- Click the Stitch button.
The "To Stitch" image tile is translated so that its overlap is precisely aligned with the "Reference" image tile. Note how the features between the two image tiles are now seamlessly blended between the two image tiles, as shown below.
- You can continue to align image tiles with Feature Base method, or you can continue to the next topic in this tutorial to learn more about the Value Stitcher.
Using the Value Stitcher and Move Tools
- Load the image stitching tutorial dataset and apply the required image grid (see Loading the Image Stitching Tutorial Dataset).
- Select the Highlight channels option in the Blend box on the Stitcher panel.
This will let you see the border of each image tile in the Stitcher workspace.
- Zoom in on the top two image tiles on the top left corner of the mosaic with the Zoom tool on the Manipulate panel.
- Click the Select (Reference) button in the Actions box and then click the image tile in the second column of the top row.
- Choose the following settings in the Stitching box:
Setting
Method
Value Stitcher
Translation in X
-0.215
Translation in Y
0
Take translation as % value
Not selected
- Click the Stitch button.
The selected image tile is translated along the X axis by the selected step size.
- Select the image tile in the second column of the top row as the Reference and then the image in the second column of the second row as the To Stitch selection.
IMAGE HERE
- Stitch the image tiles together with the default Template Matching (translation) settings (see Using the Automated Stitching Methods).
- Select the image tile in the second column of the second row as the Reference and then select Value Stitcher as the stitching method in the Stitching box.
- Click the Total transformation for selected button in the Stitching box.
The current transformation applied to the selected image tile is displayed in the Registration history dialog.
- Close the Registration history dialog.
- Make sure that the image tile you translated is still selected and then click the Copy last transformation of selected button in the Stitching box.
The values of the last transformation applied to the selected image tile appear in the Stitching box.
- Select the image tile in the third column in the second row as the Reference.
- Click the Stitch button.
The image tile is translated in the X and Y axes by the indicated amount.
- Make sure that the image tile is still selected and then click the Move
tool in the Move panel. - Manually translate and/or rotate the image tile.
- Click the Stitch button.
- Click the Total transformation for selected button to view the transformations you applied with the Move tool.
- Click the Undo button in the Actions box to undo the transformations applied step-by-step to the selected image tile.
