Image

Each photo references an image file.

To edit references use the Reference Manager.

Pose (position/rotation)

Photo position and rotation define the estimates of the photograph pose. Accurate estimates of photo poses are required for 3D reconstruction. These estimates can either:

Pose metadata (position/rotation)

Metadata position and rotation define the known pose of the photograph. This metadata can be imported from GPS tags, third-party data, or during block import.

Component

Another property of a photo is its component. Only the photos belonging to the main component of the block, i.e. photos resulting from a joint optimization, e.g. by aerotriangulation in ContextCapture or in third-party software, can be used for 3D reconstruction.

Mask

A mask can be associated to a photo to cause specific parts of the image to be ignored in the workflow. A valid mask is a black and white TIFF image with the same dimensions as the photo. Pixels of the photo corresponding to black pixels of the mask will be ignored during aerotriangulation and reconstruction.

Masks are associated to input photographs through their file name:

Example: for a photograph "IMG0002564.jpg", the corresponding mask should be "IMG0002564_mask.tif"

Masks can also be assigned to photos from the user interface once photos are loaded: right click on a selection of photos to set or to clear the attached mask.

See also Masks.

Manipulating photos

Use image GPS tags

GPS tags, if present in Exif metadata, are automatically extracted, and can be used to georeference the generated 3D model.

Incomplete GPS tags are ignored (with latitude and longitude coordinates but without altitude).

After adding photos with complete GPS tags, you are notified that GPS altitude has been interpreted using sea level as reference. Click on Modify to change the GPS altitude reference for the last added photos (Sea level or WGS 84 ellipsoid).

See also Positioning data.

Import image positions and rotations from a text file

Import photo positions and rotations from a text file

Use this option to set image positions and rotations from 3rd party data stored in text format. This import is an alternative to importing the entire block in XML or Excel format.

The Import positions button is enabled only if the block is not empty, since the aim of this tool is to pair each block photo with a line in the text file that indicates that photo's position.

For more details, please refer to the dedicated chapter Import photo positions.

Set the displayed Spatial reference system

For georeferenced blocks, use this option to change the spatial reference system used to display position coordinates. This is a display option which does not affect block properties.

See also Spatial reference system.

Downsample photos

Define a downsampling rate

Downsampling photos reduces the quantity of information to process and affects the quality of results. It may be used to quickly produce a draft 3D model or to allow to process a large imagery dataset on a computer with a low hardware configuration and/or with a limited software edition.

Applying photo downsampling does not modify input photos.

Downsampling is defined by entering the percentage of original.

Photo downsampling affects the quality of results.

Check image files

Check the integrity of image files

This tool tests all block photos in order to identify missing or corrupted image files.

Two checking mode are proposed: Check image file header only (faster) , and Load the entire image file (slower).

For convenience, if invalid image files are found, you are proposed to remove them from the block.

Preview an image

Select a photo and click on View to visualize the photo with the integrated Image viewer.

About image quality

Depending on image size, the image viewer may use a compressed cached copy of the image. Press the 'O' key to load the original image.

About image preview

ContextCapture Master generates photo thumbnails in the background to accelerate preview display.

For very large images or when images are accessed from a remote location, preview creation may slow down the interface. In such case, it is advised to disable the preview.