To begin this tutorial it is assumed that
you have a basic understanding of what HDR images are and their
importance. If not, please read What is
HDR tutorial. To learn how to merge LDR (JPG's, TIFF or RAW files) images into a single HDR,
go to Creating HDRi
Files.
Tone Mapping Operator are like filters but what
they do is compress HDR data (also known as 32bit images) LDR data (also
known as 8bit and 16bit images simply put jpg's
and tiff's). Since there are virtual an infinite number of ways to
compress the data, different Tone Mapping Operators have different
options that perform different functions. Artizen offers 3 built-in tone mapping operators called
Display, Dramatic and Natural and each of these produce a different results. Display is a very simple fast tone mapping operator that
produces results very similar to what you would get from a camera, such
that you could almost compare a single exposure to Display. Dramatic is
a complex operator that is slower than Display but it produces that
commonly referred to result as "HDR cartoonish". Although it
can produce results that are almost cartoonish it can be applied very subtly
so that it also produces very natural results. Natural like it's name
implies produces very natural results with a touch of dramatic detail.
The tone mapping interface is consistent
regardless of the tone mapping operator selected, but not all
options are available to all operators. The interface breaks down into 6
specific areas the Preview options located at the top above the picture,
and the rest (Preview Samples, Local Controls, Exposure & Color
Balance, Levels & Histogram, and Additional Options) are all located
to the left of the preview picture.
Undo Button - This option allows users to undo the tone mapping settings to their
previous values.
Redo Button - This option allows users to redo the tone mapping settings to their previous
undo values.
Dropdown List - This lists
all of the tone mapping saves that have been saved.
Delete Button - This option
deletes your tone mapping
setting in a xmp file.
Preview Samples - Allows
users to create different samples before deciding your final effect.
Local Controls - is a group
of three sliders that control local functions such as detail and sometimes
the overall strength of the tone mapping operator.
Exposure - These are global functions that control the overall look of the image
such as brightness.
Color Balance - These are global functions that control the overall look of the image
such as brightness.
Levels
& Histogram - This allows users to make final corrections (usually
after the tone mapping settings have been set) to the image before
outputting the results. The Histogram (vertical Blue Lines) displays what
the distribution of data looks like for the image shown in the right hand
side preview window.
First try to bring in as much data
to the center of the Histogram which is illustrated by the red, green and
blue lines, and the second is to try to make sure that distribution
between the dark and bright areas of the image are even.
Using Levels offer a new way of working with the Highlights and Shadows
(H&S) of an image. The key difference between the Levels H&S
options and the tone mapping options, is that the tone mapping options
only work on data that is on the bottom or top half of the histogram while
Levels works across the entire image data set. So using the H&S
options in Levels tool can increase/decrease the overall brightness of an
image.
Now if you want to reset the values of the Levels options. The
"Reset" button is located at the upper right hand corner of the
Histogram. This option is different than using the "Undo"
settings button located at the top.
At the very bottom of the Tone Mapping window are several additional
options that can be used to determine the type of image you are using and
how you would like the output to be.
Additional Options
Noise Reduction - Some tone mapping operators can produce
to much noise in the final result and even though this can be controlled
by using a Details option, it will also change the overall appearance of
your image. The Auto Noise Reduction option on the other hand will will
automatically reduce the amount of noise in your results while preserving
the overall effect created by the Details option.
Radiance Glow - This option
adds a Radiance glow to the entire image, which can be a very nice effect
by softening the darkest areas of photo and spreading out the light in
bright areas.
Vignette Effect - This option controls
the amount of Vignette effect is applied.
Panoramic x360 & y360 - These options have been
added to allow users to tone map their panoramic images. Since not all panoramic
images are the full 360x360 degrees these option were separated (unlike
most competitors that only handle 360x360 or 360x panoramas) so that users can
tone map their nadir and zenith fisheye images. This helps ensure that when your hdr
panoramas are unwrapped or wrapped they will produce seamless results.
Output - Depending on the intended final use of your tone mapped
hdr image, user can select to out their images as 8/16 or 32bit.
Auto Save Default Settings - Users sometimes want to be able to reset
the default values of each tone mapping operator, the auto default option
will save your settings as the new default values when you click apply.
This option is very useful when dealing with very similar hdr images that
work with the same setting values.
Save Settings with File - Users can now
save their tone mapping settings in the same location as their final image
file for reuse at future date. Loading the settings file is done by
selecting the Load Settings... option in the Drop Down List at the very
top.
Preview Options
Since each tone mapping operator takes a
different amount of time to process and the results can vary slightly based on image
size, Artizen has 4 Preview Styles; Very Fast & Low Detail,
Fast, Balanced and Slow & Detailed. A good practice is to use one of the lower Styles for
setting your values and once you are happy with your results, it is good
pratice to make sure that the results still look good on the Slow & Detailed
style. This will help ensure that what you see is what you get.
Show Out of Range Pixels - When
this option is select it shows which pixels are either over or under
exposed by displaying them as red and blue colors. This doesn't affect the
final results cause it is only for information purposes.
Learn how to use specific tone mapping operators.
Using Display Tone Mapping Operator
Using Dramatic Tone Mapping Operator
Using Natural Tone Mapping Operator
