# The PanoramIX Authoring Tool

## Version 0.1.4.92, February 26, 1998

## 4.8 The Edit Panorama Dialog

A panoramic image may be created by stitching a set of flat side images into a single cylindrical image. Equivalent images may be produced directly from panoramic cameras or other sources. In any case, the resulting cylindrical panoramic image may be loaded or imported as an alternative to a set of flat side images. In this case, since there are no flat side images to align and stitch together, there is very little additional editing that can be done.

A panoramic image may be loaded through a Raw Image Control File or by importing directly by selecting Panorama in the Import Images entry in the File menu. A panoramic scene can have at most one panoramic image. A panoramic image file and flat side images are mutually exclusive.

If the current panorama is based on a panoramic image file instead of a sequence of flat side images, the panoramic image can be modified using the Edit Panorama dialog. This dialog is opened by selecting Panorama in the Edit menu.

The Edit Panorama dialog contains five sections:

1. Panoramic Image Identification
2. Panoramic Image Properties
3. Panoramic Image Cropping Parameters
4. Other Panoramic Image Properties
5. Apply and Close Buttons

### 4.8.1 Panoramic Image Identification

The upper part of the Edit Panorama dialog provides three fields for selecting and identifying the panoramic image representing the panoramic scene. These fields indicate the names of the image files providing the sources of the color values, link values, and depth values for the current scene. Each of these fields is accompanied by a Browse button which is intended to provide the ability to replace the indicated file with other suitable files. These functions have not yet been implemented, so these Browse buttons do nothing.

### 4.8.2 Panoramic Image Properties

The Edit Panorama dialog also provides controls for the following properties of a panoramic image:

a. Clipped width of panoramic image,
b. Clipped height of panoramic image,
c. Horizontal shift,
d. Vertical shift.

These values enable one to select a rectangular subset of the pixels in the panoramic image. This could be useful for removing the scalloped top and bottom edges resulting from stitching a set of flat sides into a panoramic image. This can be accomplished by stitching a set of flat side images into a panoramic image, saving the panoramic image in a file (File>SavePanorama), then reloading the resulting panoramic image and reducing the clipped height until the scalloped areas are eliminated. This method has an advantage in ensuring that the same number of rows of pixels are removed from the top and bottom areas of the panoramic image.

Back to the Edit Panorama Dialog.

Back to the Edit Menu.

Back to the PanoramIX Authoring Tool.

### 4.8.3 Panoramic Image Cropping Parameters

The image cropping parameters make it possible to ignore or exclude all image data outside the cropping boundaries independently of the image alignment specifications. This allows one to eliminate useless or invalid image data resulting from the way a particular image was exposed, printed, or scanned. In the case of a panorama composed without blending, this has no effect on the resulting panorama unless the cropping boundaries fall within the clipping boundaries. If the cropping boundaries fall within the clipping boundaries, the areas between the clipping boundaries and the cropping boundaries are filled with black. Such areas are considered to represent "missing data" which must be filled in later using aany appropriate image processing techniques. In the case of a blended panorama, all image data outside the cropping boundaries are excluded from the image blending process. Image data within the cropping boundaries are weighted based on the distance of each pixel from the cropping boundaries. Thus, the importance of each pixel gradually fades to zero as one approaches a cropping boundary from the interior of an image, and remains exactly zero for all pixels outside these boundaries.

The Edit Panorama dialog provides controls for the following image cropping parameters:

a. Crop Left
b. Crop Right
c. Crop Top
d. Crop Bottom

A visual representation of the cropping parameters is presented in the Edit Image window where the excluded areas are shown in black.

The values of all four cropping parameters must be positive integers because these serve only to exclude areas from the blending operations. In most cases, the boundaries of the excluded areas should remain outside the boundaries defined by the clipped width, clipped height, horizontal shift, and vertical shift. Selection of cropping boundaries which pass inside the clipping boundaries is permitted, but the blended image will acquire black columns if there is no overlap between the cropped areas at the left and right edges of the panoramic image.

The values of the cropping parameters may be modified by typing new values directly into the corresponding fields in the Edit Panorama dialog, or they may be altered incrementally by clicking on the associated spin buttons. These values may also be controlled by selecting the edges of the corresponding areas represented in the Edit Image window. Initially, these values are set to zero and the cropping boundaries coincide with the edges of the Edit Image window. In this case, it can be very difficult to select these edges with the pointing device and it may be necessary to enter a small value for each cropping boundary manually to make then easier to select.

When using a pointing device (mouse) to select and drag a cropping boundary in the Edit Image window, one is not permitted to go beyond the clipping boundaries determined by the clipped width, clipped height, horizontal shift, and vertical shift. In order to force the cropping boundaries beyond this point, one must enter the cropping boundaries directly in the corresponding fields in the Edit Panorama dialog.

Back to the Edit Panorama Dialog.

Back to the Edit Menu.

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### 4.8.4 Other panoramic image properties

The Edit Panorama dialog provides controls or information for the following additional image properties:

a. Field of View
b. Panorama Radius
c. Camera Elevation
d. Image Skewing

#### 3.2.4.1 Panoramic Image Field of View Angle

The Field of View field reports the horizontal field of view associated with the currently panorama. This read-only value should indicate the maximum azimuth for a partial panorama, or 360 degrees for a complete panorama. This function is not fully implemented and may provide an incorrect value for a partial panorama. The value of the maximum azimuth may be modified by selecting the Max Azimuth dialog in the Edit Menu.

#### 3.2.4.2 Panorama Radius Values

The Panorama Radius is defined by the width of the panoramic image in pixels divided by the maximum azimuth in radians. This is a read-only value provided for information purposes. The value shown here should be equivalent to the focal length of the lens in pixel units.

#### 3.2.4.3 The Camera Elevation Angle

The value shown here is always zero and cannot be modified. This provides no information and is present only for possible future extensions to the Edit Panorama dialog.

#### 3.2.4.4 Panorama skewing value

In the processes of printing and scanning a panoramic image, it is possible to introduce a small rotational error into the scanned image. If there is such a rotational error in the scanned image, the ends of the panorama will not match correctly. This error can be corrected by shifting each of the columns based on the distance from the center column. The value indicated here represents the total amount of shifting from the left edge of the original image to the right edge of the original image.

Back to the Edit Panorama Dialog.

Back to the Edit Menu.

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### 4.8.5 Apply and Close Buttons

The bottom of the Edit Panorama dialog has two buttons labeled Apply and Close. The Apply button updates the current panorama based on the indicated properties. The Close button closes the dialog and discards any property changes entered after the most recent use of the Apply button.

Back to the Edit Panorama Dialog.

Back to the Edit Menu.

Back to the PanoramIX Authoring Tool.

Last modified February 27, 1998.
wluken@watson.ibm.com