Contents


Orthophoto Preview

After selection and loading of images from which an orthophoto is to be made, thumbnail images are shown:



You can follow the computations in the left pane of the window after all images have been loaded and the Run button clicked.

First you will see the keypoint detection phase:



Then you will see the nearest neighbour detection and bundle adjustment phases:



You may also find it useful to select one of the automatic enhancement options available in the Orthophoto Options if parts of the images are too dark or if fine detail is hard to see.  If one is chosen, you will see the Enhancing  message prior to display of the number of keypoints found in the enhanced image during initial computation in the left pane of the main orthophoto dialogue window.



If you also want to make an image of a digital terrain model, leave this box unchecked and select Generate 2D Orthophotos as well as the DTM option in the main window of Cloud Compare.

If you only want to compute orthophotos, un-check the box Use CC GUI as shown in the options dialogue.  



A click on Apply will show progress and termination windows without having to make manual selections in the Cloud Compare window.  





A window will pop offering a choice between stitching the partial orthophotos computed by Cloud Compare with Microsoft ICE if installed or displaying them in the preview window without seamless stitching:



A large number of images can be displayed.  If you have a 32 bit operating system, this permits showing and saving high resolution images without memory problems, but seams and slight discontinuities will be visible.



It may be helpful to view the result of orthophoto computation quickly in order to select or de-select partial orthophoto images which perturb it's appearance.

Click on



and if partial orthophotos (always in PNG) format are present on the current working directory along with the computation protocol which specifies their relative positions, they will be displayed.  You can repeat this without re-calculating the images even after AirPhotoSE has been closed and re-opened.  The programme records the last directory chosen and reloads the images and the computation protocol file which it may contain unless you have changed directories in another part of AirPhotoSE. Should that be the case, click on the Select menu item to chose a previous directory and its images.

This dialogue:



will be shown and the partial orthophotos will be displayed aver a click on the View item on the main menu. If there are a large number, this may take some time.  During the display process, the name of each file written will be shown on the caption.

The order  and content of the displayed partial orthophotos may be selected with a click on the Select menu item.



All available partial orthophotos on the current directory will be shown

Do not use partial orthophotos which are extremely skewed or badly exposed like ortho_11313, ortho_ 11315 and ortho_11317.png in this collection:  



Select the ones you want to use by holding down Ctrl and clicking on the thumbnail image.  When selected, it's background colour turns light blue-grey. If you want to select all or a large set, click on the first desired image, hold down Shift and click on the last desired image.  If you change your mind, click on any selected image and start again.

If you have installed Microsoft ICE and want the result without seams or minor discontinuities, click on ICE on the main menu.



When ICE completes computation, it may be necessary to choose a Planar Motion option from the Stitch-Camera Motion window which causes ICE to repeat the calculations if it defaults to Rotary Motion.

If you have selected High Resolution in OrthoPhoto Options and your machine is running a 32 bit version of Windows, ICE may run out of memory and produce this error message:



Should that happen, open the Orthophoto Options dialogue and un-check the High resolution box.  If you have a machine with a 64 bit operating system this problem will not arise. 
 

Choose Defaults and try again by clicking the Run button followed by Apply.