SpinImageViewer

Description

SpinImageViewer is an interactive display program for displaying spin images. The display tool has two viewers. On the left is the Mesh Viewer which shows the model surface mesh; the model mesh can be moved around and viewed from different positions. The current oriented point is shown in red. On the right is the Image Viewer which displays the spin-image corresponding to the current oriented point; the image can be translated and zoomed. Clicking with the left mouse button on the model in the mesh viewer changes the current oriented oriented points and its spin-image.

Files

SpinImageViewer.c Handles mouse and keyboard events and spin-image display and animation.

Interface

SpinImageViewer accepts commands from the mouse and keyboard. (Note: the commands only work if the cursor is set to the arrow cursor and is placed inside the viewing window)

Clicking with the left mouse button on the model in the Mesh Viewer changes the current oriented point. When the current oriented point changes, the spin-image shown in the Image Viewer automatically is updated.

Keyboard commands

• s - toggles the spin-image generation method between vertex-only (the old way) and interpolated points (the new way).
• i - toggles display of interpolated points. This only has a visible effect if the spin-image generation method is set to the interpolated point method. The interpolated points are displayed as green dots on the mesh surface.
• a - toggles the spin-image animation which is used to visualize spin-image generation.
• o - toggles the oriented point display. When enabled, this shows which vertices contribute to the current spin-image by showing them as blue line segments oriented along the surface normal.
• p - toggles the display of the spin-map projection of the oriented points contributing to the current spin-image as red points. The points will show up superimposed on the image viewer and on the animation plane if animation is activated.
• w - write the current spin-image to a tiff-image stored in the current directory in the form "spinimage.{vertex-number}.tiff" Output spin-images can be displayed with xv and read by other programs (this option requires the image format library (IFL), which is not currently available for linux.
• m - make the spin image stack and save to the file "output.stack" in the current directory. This operates the same as if StackMaker were called using spinMethod 2 (interpolated points)

Usage

Usage: SpinImageViewer

%S                      set model faceset filename [required]

-genStack %F %d %d %F   set spin-image generation parameters
                        [bin size=1,width=15,height=15,angle threshold=180]

-readStack %S           stack read filename [off]

-texScale %d            set texture map scale [10]

-ptSize %F              set projection point size

-gridSize %F            surface sample interval [0.100000]

-vertices               create spin images using vertices only [false]

-abBounds %F %F %F %F   bounds on alpha,beta

-white                  cause background to be white

Detailed Usage

%S                      set model faceset filename [required]

The mesh to view.

-genStack %F %d %d %F   set spin-image generation parameters
                        [bin size=1,width=15,height=15,angle threshold=180]

This option specifies the model spin-image generation parameters. Bin size is obsolete (its value is ignored). Width is the width of the spin-image in pixels (alpha direction). Height is the height of the spin-image in pixels (beta direction). Spin-images generated will have height/2 pixels above beta = 0 and height/2 pixels below beta = 0. Angle threshold is the threshold on the angle (in degrees) between the oriented point basis and the surface normals of points being accumulated in the spin-image. Detailed analysis of these parameters is given in Chapters 2 and 9 of the Ph.D. dissertation Spin-Images: A Representation for 3-D Surface Matching.

• set height and width on order of the size of the model (the default gives good results).
• set angle threshold to 180 when matching a complete model to a complete scene otherwise set it between 90 and 60 degrees.

-readStack %S           stack read filename [off]

this parameter is obsolete

-texScale %d            set texture map scale [10]

Sets the width of each bin in the spin-image in texture map pixels. A texture scale of 10 gives good appearance for the spin-images in the image viewer. If the animation is too slow, decrease the texture scale parameter.

-ptSize %F              set projection point size

Changes the projected point size. Increase for larger points and decrease for smalle points. This option is really only useful when making videos.

-gridSize %F            surface sample interval [0.100000]

This option sets the size of the grid over which interpolated points are sampled. The spacing of interpolated points can be viewed using the keyboard command "i".

-vertices               create spin images using vertices only [false]

Sets the viewer to create old style spin-images using vertices only. The keyboard command s can be used to toggle to the interpolated point spin-image generation method.

-abBounds %F %F %F %F   bounds on alpha,beta

Sets the size of the spin-image's region of influence. The order of parameters is alpha min, alpha max, beta min, beta max. Alpha is the dimension in the radial direction (along the surface tangent), and beta is the dimension along the surface normal axis. For example, to create a spin image with radius 200 and height 100, use -abBounds 0 200 -50 50. Typically, spin-image radius and height are chosen to be equal.

-white                  cause background to be white

This is for taking screenshots. The white background looks better when the image is printed.

Examples

To view spin images using default settings

SpinImageViewer model.wrl

This example displays spin images 10 pixels wide and 20 pixels high, with and angle threshold of 60 degrees, and a physical spin-image size of 100 by 100 sensor units.

StackMaker model.wrl -genStack 1 10 20 60.0 -abBounds 0 100 -50 50