Interacting with the scene Window

We can use the GUI interactively to select regions of interest (ROI) in the scene window. We can also extract data from an ROI by script and plot the scene energy, photons, or reflectance from the ROI.

In most cases the data we plot are stored in the plot window within a variable, 'userdata' that is attached to the figure.

See also: scenePlot, ieRoc2Locs, vcGetROIData

Copyright ImagEval Consultants, LLC, 2010



Plot scene data

scene = sceneCreate('macbethd65');

% Here are the luminance data from a line
rows = round(sceneGet(scene,'rows')/2);

The plot function returns the data and a handle to the window

[uData, h] = scenePlot(scene,'luminance hline',[1,rows]);

% This structure contains the data in the graph

% This structure is also attached to the figure
uData = 

        pos: [1x96 double]
       data: [96x1 double]
        cmd: 'plot(pos,lum)'
    roiLocs: [1 32]

ans = 

        pos: [1x96 double]
       data: [96x1 double]
        cmd: 'plot(pos,lum)'
    roiLocs: [1 32]

Scenes store information about the illuminant

scenePlot(scene,'illuminant energy');

You can plot the spectral radiance energy from within an ROI

rect = [51    35    10    11];   % Yellow Macbeth patch
roiLocs = ieRoi2Locs(rect);      % xy locations in scene
scenePlot(scene,'radiance energy roi',roiLocs);

Or plot the mean quanta (photons) at the same location

scenePlot(scene,'radiance photons roi',roiLocs);

Or plot the reflectance


To read the photon data without plotting

radiance = vcGetROIData(scene,roiLocs,'photons');
radiance = mean(radiance);

wave = sceneGet(scene,'wave');
plot(wave,radiance); grid on
xlabel('wave (nm)'); ylabel('Radiance (q/s/nm/m^2/sr)');

Or read the energy data

radiance = vcGetROIData(scene,roiLocs,'energy');
radiance = mean(radiance);

plot(wave,radiance); grid on
xlabel('wave (nm)');
ylabel('Radiance (watts/s/m^2/nm/sr)');