spatial texture analysis menu

This menu lets you perform spatial texture analysis on greyscale images. Before you can use it, you must create a punch-out bitmap, which makes the software consider only a restricted set of pixels from your greyscale image when it performs the analysis. The menu performs three main functions:

It lets you create a co-occurrence image, which shows the relative intensities of pixels that bear a particular spatial relationship to each other.
It lets you generate a file containing statistical measures from the co-occurrence image.
It lets you create a new bitmap by lassoing regions of the co-occurrence image, just as you do in color-space segmentation.

The procedure for creating the co-occurrence image is as follows:

Enter the names of your greyscale image and punch-out bitmap in the B&W image and Bitmap image menu fields. These two images must be the same size.
Define the spatial relationship between pixels by entering offsets in the X-displacement and Y-displacement menu fields. These offsets tell the system which pixels to compare when generating the co-occurrence image. For example, if X-displacement = 1 and Y-displacement = -3, the system will compare each image pixel to the pixel one column to the left and three rows below it when creating the co-occurrence image.
Click on DISPLAY CO-OCCURRENCE IMAGE to display the image. This image is similar to the cloud diagrams used in color-space segmentation. The X-axis is intensity of the reference pixel, and the Y-axis is the intensity of the offset pixel. The blue pixels in the image represent combinations of reference and offset pixel intensities that never occur. Non-blue pixels are brightness-encoded to indicate how frequently particular reference and offset intensity combinations occur in the image.
You can save the co-occurrence as a Screen image by entering a name in the Image name menu field, and then clicking on SAVE CO-OCCURRENCE IMAGE.
You can create a file that lists various statistical measures of the co-occurrence image. To do so, enter the name you want for the file in the Statistics file menu field, and then click on SAVE STATISTICS.

To perform a segmentation, you draw polygons on the co-occurrence, just as you do in color-space segmentation. The procedure is as follows:

Enter the color you want for the selected pixels in the Highlight color menu field.
Click on ADD POLYGONS. Now draw a polygon on the co-occurrence image, using button 1 of the mouse. Click button 2 or 3 to terminate the polygon.
Click on DISPLAY HIGHLIGHTED IMAGE to display the selected pixels.
You can remove polygons you don't want by clicking on REMOVE POLYGONS and then clicking within the polygon you want to remove.
When you are satisfied with your segmentation, enter a name for the bitmap in the Bitmap file menu field, and then click on CREATE BITMAP.

You can control whether the system run-length encodes the bitmap by setting the Run-length encode? toggle. As in color-space, you can save your polygon definitions by entering a pick file name in the Pick file menu field, and then clicking on SAVE PICK FILE. You can recall such a pick file by clicking on RECALL PICK FILE.