Step 3: Image Files

This wizard step relates the images that are defined in the project in the previous step, to their respective physical image files, and creates accelerated access to the imagery.

Although in most cases the images to be processed will be provided alltogether on the same folder, the images in one project may be made available in different environments e.g.:

1. All the images are available on your local hard disk drive.
2. All the images are available on one hard disc somewhere in your local netwerk (LAN).
3. All the images are available on different hard discs spread over your local network.

The next display shows step 3 in the project wizard while creating a new project:

If you have image files (e.g. jpg or uncompressed tif), Strabo can provide multiresolution and compression to your images and thereby optimize their access speed during viewing.

If you have the images available in a multiresolution format like 'omi' (Orbit's native Multiresolution Image format), MrSID, ECW or Tiff, then you still have to run through this step for creation of the .oid files (see OrbitGIS).

If your images are jpg or uncompressed, we strongly advise to convert the images to 'omi' format for access-speed considerations.
Omi format contains multiresolution and compression, also omi-lossless is an option.
You may prefer to convert to another compressed format containing multiresolution information like Ecw, MrSid, or Tiff, but you need to provide the correct licenses for formats like Ecw or MrSID from the original format provider. Reading Ecw or MrSid is supported without specific licenses.

This button opens the standard OpenGIS Toolbox dialog giving you the opportunity to convert your imagery into a format containing multiresoultion and/or with compression.
See also Orbit GIS toolbox for more help regarding the Toolbox.

After converting the images it is best to move all the original images to one folder, and the new images (other format like 'omi') together into another folder.

Press the 'Prepare Images…' button and you will see the next dialog window:

Follow the next steps:

1. Select the network path where the images are located. (“\\servername\dir1\….”, or “F:/dir1/….”)
2. Select the correct type of image file format. (e.g. tif)

After selecting the image format, the dialog will be filled with the available images:

1. Select images:
   1. individualy
   2. all images (ctrl a)

1. Press the 'Go' button to create the multiresolution files.
   

The progress bar shows how the process evolves.

1. Press the 'Cancel' button to interrupt the procedure. This action will remove the unfinished multiresolution data made for the busy image.
   To continue afterwards, press 'Go' to continue this process on the same directory and with the same Image Format selected.
   
2. Press the close button to continue with the next step in this wizard.
3. If the progress bar mentions “File not found” , then these files are not available anymore on this directory, meaning that the multiresolution files are already made.

What happens during the creation of the mutiresolution files?

• If the original image files are on the same directory, each of them will be replaced under a unique subdirectory bearing the name of the image.
  
• Keep in mind that this will speedup the image access considerably, without any loss of image detail.
• Next to the image file, 4 files with extension 'oid' will be created.
  Each of them is used to access the image's multiresolution data in an adequate and performant way.
  The syntax of the 4 files is: {image filename}.{[0,90,180,270]}.oid,
  [0,90,180,270] indicating the rotation of the image (expressed in DEG) when shown in a viewer.

Once you have muliresolution images available either compressed like in OMI, ECW or MrSID, or uncompressed like in the Orbit Multiresolution format (see above explanation in previous step), you can link the images to the photos objects in the Strabo Project.

Some file formats you can use :

• 'oid' is the extension for the images using Orbit Multiresolution, which you can make using the first option.
• 'omi' is the compressed Orbit Multiresoultion Image file format of the Orbit Technology Toolkit. An omi-file gives a compression of about 1/10 of the original uncompressed image filesize.
• 'ecw' is the extension for the ER-MAPPER compression.
• 'sid' is the extension for the LizardTech image compression.
  

Press the “Link…” button and follow the next steps:

1. Select a directory under which some or all images are available, using the file selection box.
2. Press the 'Open' button on the fileselection box.
3. This will start a search under the selected directory to find possible images that are also defined in the project.
   It is possible that you do not find all of the images.
   A dialog shows you the result of this search e.g.:
   
   
   
   
   • Total photos in project: shows the number of photos defined in the project until now.
   • Matched photos in the project: shows the number of image files that were found under the selected directory.
   • Remaining photos in the project: shows the photos where no image file is found for, there, and consequently are not able to be viewed.
4. Repeat this 'Find…' action to look for the remaining images on other directories or on the LAN if the images are available on different drives on your network.

Pressing the “Histogram” button starts the following dialog:

1. Select the images of your choice
2. Press the “Go!” button to create histogram information for the selected images.
   The histogram data will be used enhancing the image during Stereo Vision.

Selecting this option will only allow you to continue to the next step.
Use this option if you want to continue creating the project now without imagery, but add the imagery later.

1. Go to the next wizard step by pressing the button on the wizard dialog.