Stitching

 

Stitching is the process of combining two or more images to make a single image that can be manipulated. This is most commonly applied to spine images or extremities. For example, an upper and lower CR image of the spine can be stitched together to make a single image. A Cobb angle can now be calculated based on the entire spine.

 

To stitch two images together, you must download and install the Stitching plug-in module. Once installed, the stitching control appears in the Extensions menu.

 

To activate the stitching process:

  1. Load an image into an available image frame
  2. Pull down the Extensions menu and select Stitch from the Stitching sub-menu.

The selected image frame turns into a stitching frame, with the stitching toolbar displayed along the bottom edge of the frame and the image fit into the frame size.

 

The stitching toolbar consists of tools to pan the images, individually and as a group, tack the image to the workspace, magnify and crop the image, and automatically match the images up.

 

Icon Function Mouse Function Description

Drag mode

Left click and drag

 Drag the image under the cursor around the image frame

Pan Mode

Left click and drag

 Increase or decrease the size of the images in the image frame

Pushpin Mode

Left click

 Tacks image to workspace at a specified location, multiple pushpins lock image position and angular orientation

Magnify Mode

Left click to zoom, ALT + left click to zoom out

 Increase or decrease the size of the images in frame

Crop Mode

Left click and drag

 Removes extraneous image information

 

Left click and drag

 Adjusts window and level of image

Allow Rotation

Left click and drag

 Rotates image around the pushpin

Allow Scaling

Left click and drag

 Rescales the image size when a single pushpin is inserted into image

    Enables or disables window/level adjustment

Auto Align

   Finds the best overlap for two images roughly lined up

 

To stitch images:

  1. Load the images into the stitching frame from the thumbnail panel

  2. Size the image in the frame so there is enough room to work

  3. To change the image size

    1. Use the zoom mode button on the toolbar or

    2. Dynamically alter the image size by holding down both the left and the right mouse button at the same time and dragging the mouse.

  4. Click on the Drag mode button

  5. Position the images in their approximate location

  6. Click on the Auto Align button to find the best fit

  7. Double click on the image to export it to an image frame

The stitching frame disappears, leaving a single image in the viewer which is added to the thumbnail panel. Any tool can be applied to the new image. It can also be saved to the eRAD PACS server or attached to the report as a key image.

 

To scale and rotate an image:

  1. Lock down the image using a single push pin
    1. Enable and disable rotation via the Allow Rotation button
    2. Enable drag mode to alter the size of the single image and rotate the image around the pushpin
    3. To rotate without rescaling:
      1.  Apply a single pushpin
      2. Press the Allow Rotation button
      3. Unselect the Allow Scaling button
      4. Drag the image

Once the orientation is applied, remove the pushpin by clicking on it again.

 

To crop an image:

  1. Select the crop tool
  2. Left-click on one of the corners of the image to identify the starting point of the region you want to keep
  3. Drag to the diagonal corner of the region

When you release the mouse, the area outside the region is automatically removed and cropping will be applied to only one image at a time.

 

To stitch the images:

  1. Drag the images to line them up

    1. Manually adjust the signal-to-noise ratio gauge on the left side of frame

    2. Use the Auto Align function to improve on the image matching

The signal-to-noise ratio gauge indicates the distortion between two images. The objective is to make this gauge as small as possible. While there is no guarantee the Auto Align function will produce a better signal-to-noise ratio, it can usually improve the result.

 

Note: The Auto Align function does not try to resize the image.