Using PTViewer directly with Source Photographs

  The PTZoom extension can be used to display any number of rectilinear images in PTViewer. In principle, the full spherical view may be covered that way, making the background panorama superfluous. An example of this technique is shown below. It uses 10 rectilinear images which resemble photographs taken with 35mm camera equipment and 18mm focal length lenses, and cover a full spherical view by means of two horizontal rows of 4 images each, plus two vertical images. These images may be viewed and downloaded as part of the PTEditor-tutorial. The PTEditor-tutorial also explains how to determine the position data for each source image.
 

The example below uses a mask image for each photograph. This mask diffuses the edges of the individual images. It is a b/w image where black pixels indicate transparent pixels in the corresponding source image. No partial transparency (grey pixels) are supported.

The PTViewer applet below does not display the usual progress indicator and may take somewhat longer than usually to display the image.

Each of the source images requires one instance of PTZoom. This is the HTML-code for one of the PTZoom instances:

<param name=applet1 value="{code= ptzoom.class}
                           {file=Image_02.jpg}
                           {mask= mask.gif}
                           {pan=89.5}
                           {tilt=30}
                           {rot=0}
                           {fov=102.79}">

It is perfectly feasible to display VR-panoramas this way and completely eliminate the intermediate stitching step and the creation of a single panorama file (environmental map). Besides the simplification and time saving, there are a couple of additional advantages:

• Image alignment and masking can be easily changed later at any time by just editing the HTML-code.
• Images with varying resolution may be mixed in one VR-representation, ie a small, low resolution sky image may be combined with high resolution images of more important objects.

• PTViewer is significantly faster when using equirectangular sources; typically a factor of 2.
• Download progress can not easily be indicated (only using the showhs function).
• More files have to be managed and uploaded to the webserver, and HTML-coding is more difficult. However, filesize is roughly identical in both cases, ie the 10 source images combined equal approximately the size of the equivalent equirectangular panorama.
• Source images must be rectilinear. No fisheye lens or panoramic camera can be used.