Welcome to WISER, the Workbench for Imaging Spectroscopy Exploration and Research. WISER makes it easy to load and analyze spectral imaging data sets with a variety of helpful features.
IMPORTANT NOTE: WISER is currently in alpha, which means that this documentation may be incomplete and/or out of date. Feel free to email wiser@caltech.edu if you have any questions or comments.
The goal of WISER is to provide an intuitive and configurable user interface that supports many different workflows and styles of interaction. When WISER is started, the UI looks like this:
The WISER interface provides multiple panes for displaying raster data at varying levels of magnification. The Context Pane starts out on the left side of the UI, and shows the raster data "scaled out," so that either one or both dimensions are fully visible within the pane. The primary viewing area is called the Main Window, providing more detailed interactions with raster data, possibly scaled up to as much as 1600%. In the above screenshot, no raster data is loaded yet, so these areas display "(no data)".
Across the top of the Main Window is the Main Toolbar, which provides various tools to work with raster data:
The buttons marked "Display Toggles" will show and hide specific tools for interacting with spectral data. These buttons are as follows:
These tools are described in subsequent sections.
NOTE: WISER can also be extended with custom functionality through its plugin API.
WISER provides a configuration panel for specifying common configuration across the various tools. You can access these properties through the WISER menubar. For example, on macOS you can access "WISER" -> "Preferences" to show this dialog:
These settings are saved on disk so that they don't need to be specified every time. Some additional details are given in the following sections.
WISER is capable of sending crash reports to an online service called BugSnag. This option is off by default, but it is very helpful if you turn this feature on so that application errors and crashes can be identified and addressed automatically. No personally identifying information is sent to BugSnag, but some users may still not want to leave such a feature on.
For spectral data sets that include visible-light frequencies, WISER is able to automatically choose "true-color" bands that are close to the frequencies of red, green and blue light. However, different data sets and instruments may require tweaking of what is considered "red", "green" or "blue". Thus, WISER allows the user to configure these values.
Here is a screenshot of WISER after loading AVIRIS data of the Caltech campus and the surrounding Pasadena area.
In this image, all of the different tools have been shown using the display toggle buttons in the main toolbar: the context pane, the main window and the zoom pane, as well as the spectral plot window and the dataset information window.
All of these components are dockable, and can be moved or resized within the WISER user interface. They can also be undocked from the UI, so that they appear as separate windows. Arrange WISER's user interface however you like it best!
As the snapshot indicates, the area visible in the zoom pane is indicated in the main window. Correspondingly, the area visible in the main window is indicated in the context window. (Tip: The color of this viewport highlight can be changed in the WISER configuration dialog.) Mouse-clicks or scrolling within the various display windows will update the other windows.
Mouse clicks within the main or zoom windows will also select the clicked-on pixel, and update the spectrum plot window with the pixel's spectrum.
The dataset toolbar buttons provide useful operations to switch between datasets, change what bands are being displayed, and to adjust the contrast stretch of the bands being displayed. Note that all raster display windows have one or more of these buttons, allowing for control of how raster data is displayed.
The dataset chooser simply allows the user to change what data set is being displayed in a given pane. When clicked, the dataset chooser will show a pop-up menu listing all data sets currently loaded, and selecting a different data set will switch the display to that data set.
The band chooser shows a dialog that gives the user significant control over what bands are being displayed, and whether the image is to be shown in RGB mode (three bands) or grayscale mode (one band only).
Besides letting the user select any combination of bands, the band chooser also exposes the ability to select the dataset's default bands, if any were indicated in the original data file. Finally, if the dataset specifies wavelengths or frequencies for each band, and if these wavelengths are near the red/green/blue frequencies specified in WISER's global configuration, the band chooser can automatically choose the bands closest to these frequencies.
Note that if a data set does not have default display bands, or if the data set doesn't have visible-light frequencies, the corresponding button in the dialog will be disabled.
The contrast stretch tool provides sophisticated options for adjusting the contrast of images being displayed. This allows the user to bring out details in the image data that might otherwise not be perceptible.
Here is an example of the contrast stretch tool being used with the Caltech AVIRIS data.
A histogram is shown for each display band, allowing one to see the distribution of values for that band. The user can select both the kind of contrast stretch used, and any conditioners to apply to the data before applying the stretch. Because it is useful to see the results of applying contrast stretch, changes in the dialog are immediately reflected in the affected raster displays. If the "Cancel" button is pressed, the changes will be discarded; otherwise, they will be kept when the dialog is closed.
Here is another example of applying a 2.5% linear stretch to the Caltech AVIRIS data:
When applying a linear stretch, the sliders may be adjusted to control the endpoints of the contrast-stretch operation. Additionally, minimum and maximum values may be specified, to exclude noise that appears outside the range of useful data, or to focus in on a specific range of values.
For a detailed description of how WISER performs contrast stretch calculations, please refer to this document.
WISER supports the creation of Regions of Interest (ROI) on a raster data set. Regions of Interest may be created in both the main window and the zoom window. Once a ROI has been created, the average spectrum over the ROI may be plotted, and the spectra of all pixels in the ROI may be exported as an ASCII file.
Here are the Region of Interest tools in the main toolbar:
The first button allows a new Region of Interest to be created; a dialog allows the user to enter basic details about the Region of Interest. It is recommended to use a different color for each Region of Interest to avoid confusion.
Once a Region of Interest is created, selections may be added to the ROI. The right button allows users to create rectangle, polygon, and point-set selections, which will then be added to the current Region of Interest. The ROI that the selection is added to may be changed with the drop-down combobox in the toolbar.
Tip: The status bar at the bottom of the UI provides instructions about how to create each kind of selection.
Here is the UI state after two Regions of Interest have been created - one named "grass" and the other named "solar panels". Note that the "solar panels" ROI is comprised of multiple overlapping rectangle selections (this could also be done with a single polygon selection). It is not a problem to have overlapping selections in a Region of Interest; each pixel in the ROI will only be used once by operations on the ROI.
Once a Region of Interest has been created, right-clicking in the ROI's selections will pop up a context menu providing various operations with the ROI.
