Introduction

The Radiance Image Viewer, developed by Square One Reasearch, is an alternative application for viewing and analysing images produced by Desktop Radiance, an implementation of Radiance for Microsoft Windows. It allows you to view multiple Radiance PIC files as well as perform a range of scaling, false-colouring, information-gathering and contour overlays. Simple controls allow you to set scale values and units, whilst useful command-line processing allows you to load multiple files at once using wildcard characters or even just the RIF file name.

This wiki page documents and explains the features of the Radiance Image Viewer.

Installation

The Radiance Image Viewer is already installed by default with the Radiance Control Panel and with Ecotect. You will only need to download and install this application separately if you don't already have either of these Square One tools.

You can download a copy of the Radiance Image Viewer from here. Save the ZIP archive to your computer, extract and double-click on the Setup.exe file to install the application.

Launching Radiance Image Viewer

You can launch the Radiance Image Viewer one of two ways, either as a stand-alone application, or in conjunction with 'Ecotect'. Under Windows XP, click on the Start button, navigate to the All Programs»Square One program folder, and then click on the Radiance Image Viewer icon.

Alternatively, if you use the Export Manager from 'Ecotect' to output a Radiance simulation image using the Final Render option, the resultant image will open automatically using the Radiance Image Viewer. This is the more common way to start the Radiance Image Viewer.

User Interface

The Radiance Image Viewer looks something like this when it first starts up :

The Radiance Image Viewer user interface.

Let's start by looking at the toolbar found in the main application window. This toolbar contains most of the tools and options you will use with the Radiance Image Viewer.

The main toolbar.

Window Tab
The tab labelled Test_c1.pic in the top left hand corner of the toolbar indicates the window containing the current image. Because the Radiance Image Viewer can open and process multiple images simultaneously, each of these images will open in a new tabbed window. This feature is similar to tabbed browsing as found in Mozilla Firefox.

Exposure
You can adjust the exposure (levels of lightness and darkness) in a Radiance simulation image in a similar fashion to adjusting the exposure when taking a photograph with a camera. The exposure level is set by default, but can then be adjusted to be light or darker. Simply type in the value required, and then click the green Play button to apply the exposure setting.

Lesser exposure of 0.016.

Default exposure of 0.026.

Higher exposure of 0.036.

Different exposure settings in the Radiance Image Viewer.

Note, of course, that adjusting the exposure level of an image can only partially compensate for regions of an image that are too light or dark. Also, I'm not sure how exposure is measured in the Radiance Image Viewer, but will ask Andrew and get back to you!

Information Overlay
This pull-down menu allows you to apply a range of analysis overlays upon the Radiance image. To apply an information overlay to the Radiance image, select one and then click the green Play button to the far right of the toolbar.

Because you can apply only one type of information overlay to an image at a time, you need to click back on the tab of the original image before attempting to overlay another type of analysis. However, because the Radiance Image Viewer allows you to open multiple images simultaneously, it's very convenient to click from one image tab to the next to compare the different types of image overlays.

To generate different image overlays, first click back on the original image before attempting the next type of overlay. Each image is created with its own tab, allowing you to easily compare one image to another.

There are seven different types of information overlays offered by the Radiance Image Viewer:

Contour Lines.

Contour Bands.

False Colour.

Daylight Factor.

Human Sensitivity.

Set Exposure.

Custom Scale.

Different information overlays in the Radiance Image Viewer.

Contour Lines: This information overlay generates a contour map of values based upon the selected scale and units being measured. Scale and units are discussed in greater detail in the next section, but basically the scale should be set to just above the maximum expected value, while the units are generally determined by the type of lighting analysis selected back in Ecotect.

Contour Bands: Shows each contour as a band that extends from one extremity to the other for the particular scale value.

False Colour: Creates a thermal imaging overlay on the Radiance Image. Areas of the image are coloured according to the corresponding scale value.

Daylight Factor: Displays contour lines in relation to the daylight factor percentage to which each part of the image is exposed. When you first invoke this information overlay, you will be prompted to specify the horizontal illuminance of unobstructed sky (Lux) - this is the same as the Design Sky Illuminance, as would be specified in an Ecotect lighting analysis. Note that the scale should also be set to 100, since the values are being expressed as a percentage.

Human Sensitivity: This tool is similar to adjusting the exposure, but uses a variety of nonlinear and linear filters to mimic human visual perception. This tool compresses the dynamic range so that most of the details in a high-contrast image may be displayed simultaneously, similar to the visual experience one may have in the actual space.

Set Exposure: I have no idea what this one is supposed to do...

Custom Scale: I'm not sure what this one is supposed to do either...

Scale, Divisions and Units

The next three fields of the main toolbar allow you to control the way in which data is displayed in each of the information overlays.

Scale sets the maximum value used in the range for each of the information overlays. This value should be set to just above the highest anticipated value for the image being analysed. To determine what the highest value is likely to be, click on the brightest point within the image not in direct sunlight - this will display the unit value on the image, and you should set the scale to be just above this value, perhaps rounding to the nearest ten.

Determine the highest value not in direct sunlight just by clicking on the Radiance image.

Scale set to 30000.

Scale set to 5000.

Adjust the scale to set the maximum value range to use for each information overlay.

With information overlays that use percentage values, such as daylight factor, the scale should be set to 100, naturally.

Divs, or divisions, controls how the scale increments are divided up. The greater the number of divisions, the greater number of contours or bands that will appear in the information overlay.

Contour lines with 10 divisions.

Contour lines with 20 divisions.

Divisions control the number of increments used in relation to scale.

Units allows you to specify what unit of measure is used for an information overlay. Generally, there is no need to change this - the units are automatically configured either based on the settings selected in Ecotect (eg. luminance vs illuminance), or determined by the type of information overlay (eg. percentage values for daylight factor).

However, should you need to specify your own units, simply type in the units required. Note that this does not change the values being analysed, merely the unit type that is specified in the scale bar. For example, you cannot convert a luminance image into an illuminance image just by changing the units from cd/m2 to Lux - you would have to regenerate the image using the appropriate settings back in Ecotect.

Bananas are generally not recognised as SI units.

Menus

There are four menus in the Radiance Image Viewer :

Things to document :

File Menu : - Open Image(s) - Save Displayed Image As - Copy Image to Clipboard - Copy Status Data to Clipboard - Close Displayed Image - Close All Images - Exit

Options : - Fit Window to Image - Stretch Image to Fit - Centre Window - Transparent Data Values - Repaint Image - Settings...

About :

Help :

Scale

Divs

Units

Right-click context menu : - Close Image - Copy Image to Clipboard - Copy Status Data to Clipboard - Fit Window to Image - Repaint Image