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.
Since most tone mapping operators can be fine tuned, Artizen also allows users to
adjust up to 10 configuration settings for almost all tone mapping
operators. In addition to this, Artizen has the ability to adjust the
image using a built-in Levels tool, which is available to all tone
mapping operators.
When using the Tone Mapping window, user are provided with
a wide selection of productivity tools that help user deal with a large
selection of HDR images.
Across the top of the Settings options is a grouping of 5
buttons. These buttons help users to work with the different settings that
can be adjusted to tone map an hdr images.
Load Button - This option loads xmp tone mapping
files for both Photomatix and Artizen.
Save Button - This option saves your tone mapping
setting in a xmp file, which can be loaded to be applied on another image
at a later time.
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.
Defaults Button - This option restores the tone
mapping settings to their startup values.
Below the Settings buttons are the actual different
Tone Mapping settings. There are 4 ways of working with values depending
on the amount of change you want to apply to each value. The simplest and
most common way is by left clicking and dragging the slider to their new
position. This is very useful when you want to make large changes to
values. The second method is by manually entering the intended value
directly into the value text box, which is also very useful when large
accurate changes need to be made. The next two methods are for fine tuning
the values by small increments. The simplest method is to click on the
left or to the right side of the slider controller, which increments
values by +/-0.1 values. The last option is to use the left and right
arrows located to the left and right of the slider, this method is the
most granular method of controlling the values.
Directly below the tone mapping settings is the Levels
& Histogram option. 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.
The Red Line is referred to as the Luminance
Distribution Curve (LDC), which like the Histogram displays the
distribution of pixel values indicating if the image is weighted to the
dark or bright side of the histogram. In virtually 95% of all situations
the goal is to try to get this line to be as straight as possible, which
would indicate the image is rather evenly distributed.
Using these 2 indicators a user will try to achieve 2
specific goals. First try to bring in as much data to the center of the
Histogram which is illustrated by the blue lines, and the second is to try to make
sure that distribution between the dark and bright areas of the image are
even which is illustrated with the red line.
To help this process, the Levels controls (arrows located
below Histogram) can be used to finalize the adjustment process before
final output. The vertical white lines have been added to help provide
better indicators of the exact positions of each Levels control.
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.
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.
Auto Preview - Some tone mapping operators can take time to
process, and thus slow down the change of each slider value. This option
was added so that values can be change without automatically updating the
preview option. Once the settings have been changed to the users liking,
checking this value will automatically display your output in the right
hand side preview window.
Auto Default - 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.
Auto 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.
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.
Apply Button - This button applies the tone mapping
operator but rather than converting the image into 8bit or 16bit it leaves
the image in 32bit float data, which allows users to apply multiple tone
mapping operator in a specific sequence. The example below illustrates
that the combination can produce better results than either could
individually.
See Before/See After Button - This option allows
users to quickly go back and forth between the Original HDR image and the
Tone Mapped results.
Artizen supports 5+ tone mapping operators, selecting
which operator you want to preview and apply for your final output is done
by simply selecting from a drop down list. Since each operator takes a
different amount of time to process and the results can change 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 a good
idea to make sure that it still looks good on the Slow & Detailed
style. This will help ensure that what you see is what you get.
Learn how to use specific tone mapping operators.
Using Display Tone Mapping Operator
Using Dramatic Tone Mapping Operator
Using NAtural Tone Mapping Operator
Using Cipher Tone Mapping Operator
