Creating Mosaics & Image Stitching in AltairCapture (shortcut = Shift+T)
Stitching or “Mosaicking” combines multiple photographic images with overlapping fields of view to produce a single high-resolution image. Nearly exact overlaps between images and identical exposures are required to produce seamless results. Using AltairCapture it is possible to create digital maps, enhanced microscopy or medical images, or multiple image super-resolution astronomy images. Resulting images can be projected onto Plane, Cylindrical, Spherical, Fisheye, Stereographic, Mercator or Transverse Mercator map surfaces. The Default is Cylindrical.
AltairCapture has 3 stitching methods Video Stitch, Image Stitch and Browse File Stitch.
Method 1, Video Stitch:
When the video window is active, choosing the “Process > Stitch” command will invoke the video Stitch dialog as below:
Snap: Click to capture image from camera. One should try to move the slide to a position to capture the desired images. As you move the sliders, the next image should have some overlaid areas with the previous image.
Reset: When an image or images are captured, the Reset button is enabled, clicking Reset will remove all images from memory. It will be disabled when there is no captured image in memory.
Snap: Snaps a single image from the camera.
Cancel: Clicking cancel stops the stitching process.
Next>: Clicking Next> go to next step in the process.
Finish: Clicking Finish will begin to stitch the captured images according to the settings you’ve just made.
Panorama Straighten: Controls the image stitching direction. It can be Horizontal, Vertical or None. Default is Horizontal.
Projection Type: For image segments captured from the same point in space, stitched images can be arranged using one of various map projections. AltairCapture includes Plane, Cylindrical, Spherical, Fisheye, Stereographic, Mercator or Transverse Mercator map projections. The Default is Cylindrical which can be useful for planetary imaging.
Seam Finder: Controls the seam matching and finding method, AltairCapture includes None, Voronoi Diagram, Graph Cut Color or Graph Cut Color Grad. Default is Graph Cut Color.
Exposure Compensation: Exposure Compensation is required between images to minimize exposure differences. AltairCapture includes None, Gain or Blocks Gain Exposure Compensation methods. Default is Blocks Gain.
Bundle Adjust: Bundle Adjustment is an algorithm which attempts to solve the problem of simultaneously refining the 3D coordinates describing the scene geometry, as well as the parameters of the relative motion and the optical characteristics of the camera(s) employed to acquire the images, according to an optimality criterion involving the corresponding image projections of all points. AltairCapture can use Ray adjust or Reprojection error bundle adjustment methods. Default is Ray adjust.
Match Confidence: 1~100, Default = 65.
Panorama Confidence: 1~100, Default = 100.
Match Strength: 0~100, Default = 25.
Blend Strength: 0~100, Defaults = 5.
Defaults: Clicking Defaults will set all parameters to Default.
< Back: Clicking <Back will return to the previous step.
Finish: Clicking Finish will begin to stitch images according to the above setup. After the Finish button is clicked, AltairCapture will start to stitch, and a progress dialog pops up.
Cancel: Click to cancel the stitching process.
The final stitched image will be created in a new image window which can be saved.
In the stitched image, there are can some junctions visible between areas; these are caused by realtime changes among the image edges in either direction, caused by air-motion, for example. Increasing the amount of overlap can help reduce this. In most situations this isn’t visible, but some touchup might be required in Photoshop or another imaging application.
Method 2, Image Stitch
If a set of images are opened in AltairCapture, for example stitch001.jpg, stitch002.jpg, stitch003.jpg, and stitch004.jpg are opened as shown below:
Then choosing the Process > Stitch command will invoke the Image Stitch dialog boxes as follows:
The Available Images box: After you click Snap, the images opened in AltairCapture in new dialogue boxes, and are held in memory. Here, 4x images are listed in the list box. Click the image file name to select the files to be added to the Selected Images for stitching:
The Selected Images box: The images selected for stitching. Use Add>> to add the Available Images to the list.
Add>>: When single or multiple images are selected and highlighted in the Available Images window, the Add>> button will be enabled. Clicking Add>> will add it or them into the Selected Images list for processing.
Add All>>: Clicking Add All>> will add all of the Available Images into the Selected Images list for processing.
Remove: When an image or images is or are selected and highlighted in the Selected Images list box, the Remove button will be enabled, click Remove will remove it or them from the Selected Images list box.
Clear: Used to clear all images in the Selected Images list box.
Cancel: Cancels the stitching process.
Finish: Clicking Finish will start to stitch the captured images according to your chosen settings.
Next>: Clicking Next> will go to the next step.
(The remaining steps are the same as the Video Stitch process with the final stitched image being shown in a new window when complete).
Method 1, Stitch from browsed files:
Click the Folders Sidebar to activate the file browsing menu. Double-click the right directory to show the images under the directory in the Browse window. Choosing the image files to be stitched and then clicking the right mouse button will display the context menu. Choose the Stitch sub-menu to start the image stitch operation (One can also choose using Process>Stitch, after the files are selected in the Browse window)
After the Stitch command is selected, the usual Stitch dialogue will pop up, and the rest of the process is the same as the other stitching methods.