Improve your 3D Pictures With Post-Processing - 3D-Con

Improve your 3D Pictures
With Post-Processing
How to improve the presentation of
your 3d images for competitions
By George Themelis
NSA - July 2014
Two Types of Post-Processing
A. Crop, Adjust Levels (contrast/Brightness)
B. Add/Remove Elements
PSA Division
Projected Image
Nature
Photojournalism
Photo Travel
Pictorial Print
3D
A
OK
OK
OK
OK
OK
OK
B
OK
X
X
X
OK
OK
Post-Processing Operations
You need 2 programs for post-processing:
1. StereoPhoto Maker (SPM): Software designed to work with 3D
images. You can read, view, crop, align, and save stereo images.
It works in PC computers only and it is free.
2. General Photo-Editing Program (PEP): There are a lot of programs available for general photo editing (Photoshop, etc), many
of which are free. They all do about the same things. My advice
is to learn to use one program well and stick with it.
Operation
SPM
1. Crop
Y
2. Alignment & Stereo Window
Y
3. Level/color Adjustment
PEP
Y
Crop—Why?
1. Remove unwanted/distracting Elements
2. Focus on your main subject
3. Improve composition
4. Change aspect ratio to fit the subject better
5. Change aspect ratio to fit the viewing
medium better
6. Look for a picture within a picture (useful
shortcuts F: increases picture size to fill the screen,
J: Shows picture at full resolution)
Crop—How?
With SPM, use the crop function (Shortcut: B)
A cross hair will appear on the screen
and moving around as you move the
mouse pointer.
Go to one corner to start cropping. Hold
the left mouse button down and move
the opposite corner. You will see an outline of the area to be kept.
You can release the mouse button and
click inside the area to finalize the crop or
hold the left button to make fine adjustments. Once you release the mouse
button, the image will be cropped.
To stop cropping, hit ESC. To reverse a
cropping operation, hit EDIT, UNDO
(shortcut: Z)
Cropping at a Fixed Aspect Ratio
Click at the pull-down menu
next to the cropping button
icon. Then click at the “Free
Cropping Option”
Check the box “keep Aspectratio”. Select the desired Aspect-Ratio (by typing it in the
X:Y box). Then OK.
The Stereo Window
The Stereo Window
•
The stereo window is the frame (edges) of our picture. Every picture has a frame because it ends
somewhere.
•
In stereo photography this frame takes a special
meaning. Since our pictures extend in space this
frame becomes something of a window into space,
hence the term “stereo window”.
The Stereo Window
•
•
•
Like a real window, our subject is usually behind this
“stereo window” but it can also be “at window level” or
extend forward into the “audience space” (this is known
as “through the window effect”.)
The photographer has control over how the scene is
located with respect to the window and can use this
as part of the composition.
Good placement of the subject with respect to the window (or good window placement) will improve the presentation of a 3d image. Bad window placement can be
distracting and negatively affect the presentation. Learning how to see and manipulate the stereo window is
an important skill.
The 3L Rule
A rule that I have found useful for checking for stereo window placement is the “3L Rule” which states:
“The Left eye sees Less on the Left side”
If this is true, then the object is behind the stereo window.
The 3L Rule
“The Left eye sees Less on the Left side”
To see why this is true, consider a real window. There is an area on the left side
that is seen only by the right eye (assuming that everything is behind the window.)
So it is true that when looking outside a real window, the right eye sees more on
the left side, or (easier to remember), the left eye sees less on the left side.
Where are these letters located with
respect to the window?
B is behind the stereo window,
W is exactly at window level,
F is in front of the stereo window.
The letter W has exactly the same distance and this is the
reason it lies exactly at the window. The letter B is closer to
the left edge on the left image and further on the right.
You can tell that B is behind the stereo window because
the left eye sees less on the left side”
(The opposite is true for the letter F.)
Objects WRT Window
Things are even easier with overlapping
images (anaglyph, projection, etc)
The rule for window placement now says:
If the two images overlap, then the object is at window level. If the right image is on the right side of
the left image then this object is behind the
window. If the right image is on the left side of the
left image then this object is in front of the window.
Let me emphasize again that it is not necessary to
view an image in 3d to tell how an object is positioned with respect to the stereo window. All you
need to do is to study the relative displacements of the
right and left images for this object.
Window Control
• To set the stereo window so that an
object is at window level, for example,
all you need to do is shift the images
horizontally so that the left and right
images of that object overlap (or have
the same distance from the edge of
the stereo image).
• To move the entire scene back (away
from the observer), increase the
separation of the R and L images.
• To move the entire scene forward
(towards the observer), decrease the
separation of the images.
The window is controlled by adjusting the horizontal spacing of the Right and Left images with respect to each other
Window Control in SPM
With SPM you can adjust the stereo window in two ways:
1) While viewing the image in 3d (anaglyph works for any computer monitor) press the R or L arrows. Pressing the right
arrow (→) increases the separation and pushes the scene
back (away from the observer). Pressing the left arrow (←)
decreases the separation and pushes the scene forward
(towards the observer).
2) Go to “Easy Adjustment” (Adjust, Easy, or just hit “K”). You
will see an anaglyph image with the H (for Horizontal Adjustment) bar at the top. Moving the images horizontally via this
control adjusts the stereo window.
After you are satisfied with the location of the stereo window remember to save the image (SPM will not remind you.)
Window Violation
Window violation is the situation where an object
“goes through the window” but it is being cut by the
edges of the window.
This cannot happen in real life. For something to
go through a real window, it has to clear the edges of
the window.
A window violation presents a conflict to the brain
and it is confusing and undesirable.
Types of Window Errors
•
Extreme violation: The entire scene is in front of the
window. In this extreme situation the window is not well defined and beginners have a hard time recognizing what is going on. The image often looks fine
except for the “floating edges” (bands on either side of the image that appear to
belong nowhere.)
•
•
Vertical violation: This is the classic window violation
with the subject being cut by the vertical edges of the
window.
Horizontal violation: The subject is being cut only by
the horizontal edges of the window. This is not as severe as the
vertical violation and it is sometimes acceptable (except for purists who demand
absolutely no violations.)
•
Entire scene too far behind the window for no good
reason.
Optimal Window Placement
For me, optimal
window placement happens when the
near object is close to the stereo window (or allowed
to go through without a violation) and the background
can be fused comfortably. There is usually a range that satisfies
these requirements and the exact placement of the window is subjective.
Window Placement Guidelines
1) Scene with good depth range: The near object can be placed at
window level or made to go through (if it does not touch the edges, i.e.
without window violation).
2) Scene with limited depth range: The near object can be placed behind the window, leaving a bit of space between the window and the
near object. This “breathing space” emphasizes depth in a scene that
lacks sufficient depth on its own.
3) Scene with extreme depth: There is no satisfactory placement of
the stereo window. If you place the near object at window level, then the
infinity will have too much separation and cannot be viewed comfortably. If
you reduce the infinity separation (bring images closer together) then the
near object will violate the stereo window
.
My personal recommendation for #3: If there is no way to crop the image to reduce depth (by
cutting off distant background or an object too close) then one has to choose between two
“evils” - a) extreme separation or b) window violation. If the main interest is in the near object
and the background just “happened to be there” then I will go for (a) (frame the foreground
well and forget the background). If the main interest is in the background (and a piece of leaf,
a tree branch, or a ground object happened to be too close) then I will go with (b) (reduce the
separation of the images to fuse the background comfortably and let the foreground violate
the window.) But the best advice is to avoid situations like #3 while composing the picture.
Do not come too close to the near object without blocking the background.
Auto-alignment with SPM
SPM can set the stereo window during auto-alignment.
This is possible because the
program knows the near and far
objects.
How SPM handles the stereo
window depends on how the
preferences are set.
Default value will set the stereo window at the near object
if the infinity separation is not
excessive. This is the best
choice for the beginner, in my
opinion.
What Else Can SPM Do?
We have shown:
•
Cropping
•
Alignment
•
Setting the stereo window (horizontal alignment)
Other operations I have found useful:
•
Color correction (minimize differences in color between
R and L views)
•
Rotation (to straighten the horizon)
•
Adjust horizontal perspective to straighten vertical lines
Easy Adjustment (K)
Advanced SPM Operations
Add/Remove Elements
•
Clone brush (to remove objects that appear in one view
only)
•
Spherical Transformation (Ctrl+U)
•
3D Mirror Effects (Ctrl+W, Alt+W)
•
Combine/Add stereo pictures (“Add Logo”)
SPM is a living, breathing, evolving program. Functions are
being added constantly, as its creator (Masuji Suto) sees fit.
Levels/Color Adjustment
Is it necessary?
90% of the times an image can be improved (some
times just slightly, some times a lot) by adjusting levels.
Is it fair?
• It is fair that some film photographers use Velvia to get more saturated colors?
• Is it fair that one can select an option in the camera to increase color saturation?
• Since a lot of people use modern digital cameras in Auto mode, it is the camera that
makes decisions regarding exposure, not the photographer.
• Is it fair to use SPM to crop and adjust the stereo window? (Why not accept the stereo window choice that Fuji makes?)
• Some people seem to invest more time in photo-manipulation than picture taking.
• Life is not fair in general.
How to go about it
•
Buy/download a photo editing program and
learn how to use it (read the manual or study the
maker’s web site for tutorials, read a book, take a
class, watch YouTube videos)
•
•
•
Practice!!
Calibrate what you see in your computer monitor with what you see in the projection screen
Be careful of over-processing
Photoshop Elements 1
I used Photoshop Elements 1 for years now (got it for free with a Scanner) and I am very used to it. I attempted to update to version 10 (right now it is up to 12 but found it confusing and returned it). You can do a lot of things even with
an older program like this. It boils time to how much time an inclination you have to invest in using the program.
Photoshop Elements 5
Last year I used Photoshop Elements 5 and found a lot more options, sliders, etc. “Auto Smart Fix” is an attempt by
the program to make any adjustments it seems necessary. “Adjust Smart Fix” allows you to control the level of these
adjustments,
SNS-HDR
HNS-HDR is a program designed to process HDR (High Dynamic Range) images. But you can just process one image, which is basically optimizing levels and pulls out some details). The same effect could be achieved by any photo
editing program. The Lite version is free and Masuji has included a command <Alt><H> to create a batch file and do
batch processing of images.
Adjusted in PE
Original Image
Processed with HNS-HDR
TOPAZ LABS
“Make beautiful images with
our powerful photography software and Photoshop plug-ins”
Post-Processing Summary
You need 2 programs for post-processing:
1. StereoPhoto Maker (SPM)
2. General Photo-Editing Program (PEP)
Operation
SPM
1. Crop
Y
2. Align & adjust the stereo window
Y
3. Color correction, rotation, perspective
Y
4. Add remove elements
Y
5. Level/color Adjustment
PEP
Y
Y