Tutorial: Direct Depth Map

GUG Soft Home 3D Gugle Home
Attention if you cannot see all the images on this page you will need to "Refresh" it. Right-click with the mouse button and select"Refresh".
Choose a language to translate this page	Search in 3D Gugle User's guide

In this laboratory you can create or modify the Depth Map, the method used in this LAB is simple and rapid, similar to other methods used in all of 3D Gugle's LABs.

Independent of the type of activity, it is always possible to visualise in real time a preview of the work.

The Depth Maps produced in this LAB are of a standard type and therefore usable with other independent software.
With "Direct Depth Map" it is possible to operate in three different ways.

1) Sketch
With this method, depth maps are simply created by drawing with the mouse.

2) Conversion 3D
With this method, normal images or sketches are simply converted to a Depth Map.

3) Corrections
With this method, you can modify existing Depth Maps, not only those created with 3D Gugle but also those created by independent software applications.

One Note
3D Gugle is designed to operate in multi-session mode.
This allows you to open multiple instances of 3D Gugle.
This is useful in many cases, but it is essential when the new Depth Map is used with independent software applications.
The multi-session mode allows you to make changes to your depth map and then to immediately move to another 3D Gugle instance or to the independent application that uses it.

After opening an image that you wish to use, select "2D to 3D/Direct Depth Map".

In the new environment of "Direct Depth Map" the preceding menus are replaced with other menus relevant to the specific job.

Save Depth Map

With this menu you save the Depth Map.
The Depth Map is saved in the standard 24 Bit greyscale format.

Attention
To save your Depth use a lossless format such as “*.gna, *.bmp" or "*. png."

The saved Depth Map is different from the depth map being worked-on, the difference being that the work depth map has a minimum numerical value of 80 whilst the saved one has a minimum value of zero.
When 3D Gugle saves the file, it automatically converts your working Depth Map to a standard Depth Map.

The 3D Gugle working depth map has a minimum value of 80 to provide greater visibility.
A Depth Map with a minimum value of zero is extremely dark and therefore difficult to work on.

With this menu you save the Depth Map and the preview only as images.
The image arrangement is side-by-side .

The purpose of this function is that it allows you to analyse your work using other 3D Gugle functions.
For example, it is possible to convert the side-by-side images into anaglyphs or to check various parameters with the Stereo Analysis LAB.
These analyses are generally performed in another session of 3D Gugle opened at the same time as that used for creating the Depth Map.

Menu Edit

Copy Depth Map

With this menu, the Depth Map is copied to the clipboard.
The purpose is to quickly transfer, without saving, your Depth Map to another 3D Gugle session or to an external application that uses it.
Before copying to the clipboard, 3D Gugle converts your Depth Map into a standard Depth Map with the value zero as minimum.
For further information see: Save Depth Map

Menu Graphics

Auto 3D

Auto 3D is a function that creates the base of a Depth Map in automatically.

Auto 3D's algorithm operates on the luminance value.
In other words, it tries to imitate the human eye by putting greater relief into the lighter objects.

Although the Auto 3D effect is applied to the entire image, it is easy to cancel it in selected areas by moving the mouse with the left key depressed.
If you make a mistake, restore by moving the mouse with the right key depressed.

When this menu is selected, a new dialogue is displayed.

This menu serves for converting a existing depth Map from 3D Gugle, or an independent application that uses a base 80 minimum level.
The purpose is to be able to correct or to edit these depths map.

When this menu is selected, a new dialogue for setting the depth parameters used in the conversion is displayed.

Convert Depth Map to Stereo

This menu serves for converting a existing depth Map from 3D Gugle or created with software of other brands in a Depth Map base 80 of 3D Gugle.
The purpose is that to be able to correct or to modify these depths map.

When this menu is selected a new dialogue appears for to control of the parameters of the numerical proportion used in the conversion.

The conversion function is very powerful and uses an algorithm unique to 3D Gugle .
At the same time as the depth map is converted, a stereo-pair preview is also created.
The stereo pairs so created allow you to verify (by freeviewing cross-eyed or parallel) in real time the result and accordingly you can adjust the 3D to your requirements.

On pressing the OK button, the Depth Map is memorized and is ready to be corrected or modified by your mouse.

Parallel View

By default, the preview stereo is in cross-eyed format and the mouse works in the left window.
If you prefer the parallel-eyed format, click on this menu.
Attention
When you opt for the parallel-eyed format, the mouse operates in the right window .

Restart
"Restart" cancels all the performed operations, restoring the memory and image to their original state.

Menu View

With this menu the work area can be magnified in order to work with greater precision on small details.

If the option "Window" is activated the image is automatically resized when you change the dimension of the main window.

The menu: "Trace" contains the options to change the size of the chisel and to activate the Box.

Trace: "Numerical menu 2-64" changes the diameter (of a circular chisel) or the side (of a square chisel).

The use of the function keys is preferable because it allows for rapid change without removing the chisel from the area being worked-on.

Trace: "Box" The "Box" tool is very important and provides two functions, the first acts as a chisel but with the ability to operate on large areas, the second defines a visual reference guide that helps you avoid unnecessary retouching work.

The Box is enabled by pressing the "Space Bar" key and cancelled pressing the "c (Cancel)" key.

Trace: "Centre Box" When the Box is shown this menù is active and it positions the Box to the centre of the window.
This function is essential when the image area is large because it allows you to immediately recall the Box into the work area without having to seek it by moving the scroll bars.

Trace: "Trace Type" From this menu it is possible to choose a circular or square chisel.
The circular chisel is the most useful in the majority cases but for the straight lines it is essential to use the square form.

Menu Level

Menu: "<-": Pressing this pushes the perspective planes backwards. if you observe the image with a cross-eye method it will appear more distant
Menu "R=n": This menu is inactive and serves only to indicate which perspective level you are currently at.
Menu: "+>": Pressing this pushes the perspective planes forward, if you observe the image cross-eyed it will appear nearer.

Menu Stereo

With this menu you select the operational method for the creation of the Depth Map.

When the menu text is: "Stereo", pressing the menu displays the preview for freeviewing in crossed/parallel format.
You use this method when a new Depth Map is created simply by drawing it with the mouse or when an existing Depth is modified

When the menu text is: "Image", pressing the menu displays the image loaded to the start of "Direct Depth Map."
You use this method when you want to convert an image or a sketch into a Depth Map

The change from "Stereo" or "Image" can be performed in an instant without any problems.
For instance, if a sketch is converted by pressing "Stereo" the preview of the work can be visualised in crossed/parallel format.

Special Menu (Mouse and keys)

Mouse: Mouse: The chisel is enabled by pressing the left button and cancelled (restore) by pressing the right button.
This way of operating is perfectly natural and learned in the blink of an eye.

Box: The Box operates like a chisel but works by pressing the spacebar and restores by pressing the "c" key.
The Box can work even if dragged by the mouse.

Key "Z": The "Z" key, if pressed, highlights the area of the job at the current depth, it returns to the normal state by pressing "Z" or making a click on the image with the mouse.

key "Shift": Pressing this key allows direct selection of any depth plane.
For further information on this feature, click here

"Depth Map"

A Depth Map is an area of memory that contains for every coordinates X and Y (pixel) of your image a numerical value.
The numerical value normally represents a depth but for stereo applications it represents the displacement, to the right, of an image pixel from its original location X, Y .

The numerical value has a range from 0 to 255.

The Depth Map has the advantage that the numerical value can also be visualised in graphical form.

Seen graphically, a depth map is displayed as a greyscale image.
Dark tonal values represent points most distant from the observer.

The graphical display of the Depth Map is intended to give an overall impression rather than permitting precise evaluation

This is partly due to the limited sensitivity of the human eye to small differences of tonal value and partly due to the limited ability of monitors to display small differences of tonal value.

To reduce this problem, 3D Gugle uses a minimum value 80 and not the zero of the standard Depth Map.
The value 80 allows best visibility for working but it is only temporary because when the Depth Maps are saved, or you copy them, they are converted to base zero.

The project of "Direct Depth Map"

The Direct Depth Map project is organised on three windows.

The first window, that to the left, shows the Depth Map being created, the Depth Map is shown in two-dimensional form and the depth planes are indicated by greyscale values.

The left window is always displayed.

All the actions performed with the mouse or with the Box act on this window.
The right window contains two windows but only one at a time can be displayed.

The window actually displayed is selected with the menu: "Stereo" or with the menu: "Image".

When you press the menu: "Stereo" the menu text "Stereo" is hidden and the menu Text: "Image" is displayed, equally pressing the menu: "Image" hides it and menu "Stereo" is again displayed.
When you enter this laboratory, the right window contains the original image and the laboratory is ready to operate in "Conversion" mode.

The right window can not only display the original image, but also the stereo preview of the depth map.
The preview stereo window is in real time and can be freeviewed in crossed/parallel format.

To change the "Depth Level"

Normally, in 3D Gugle's conversion LAB's, the depth planes are changed using "<- " and "+> ".
That method also works here but a specific option has been implemented for the Depth Map that allows you to operate with greater precision and resolves the difficulty of discriminating small differences of grey tonality.

To select and work at any depth level you simply select the level's colour with the mouse.
The selection procedure is very simple.
On pressing the "Shift" key, the cursor changes into a crosshair shape.
The "Shift" key is used in combination with other keys to write in upper-case. On ordinary keyboards there are two Shift keys, one small to the left and a wider one to the right.
Clicking with the mouse's crosshair cursor on a colour, makes the depth level associated with that colour active.
Clicking the level again de-activates it and the menu: "Level=n" displays the number of the new level.

"The double cursor"

To have an exact point of reference in which to operate in this laboratory, the mouse and the Box have dual representations.
The mouse is displayed in the work window of both the reference image and stereo preview.

When the stereo preview is active, and you are viewing in cross-eyed mode, each "<-" click moves the right image and its cursor one pixel to the right.

"A suggestion"

All of the 3D Gugle conversion laboratories use the same principles and user-interface and for this reason it is recommended that you previously learn and use "Direct Anaglyph" and gain some practice with it.

In the "Direct Anaglyph" section of the tutorial, all the functions are described in detail together with practical examples of the various menus and suggested working-methods.

With this method you can create a new Depth Map simply by drawing it with the mouse.

To use this method it is necessary to first establish the dimensions in pixels of the panel that will contain the new Depth Map.

Before entering "Direct Depth Map", in 3D Gugle select "File/New Canvas".
In the dialogue box, enter the desired dimensions in pixels and, importantly, select the black colour.
Having done that, select "2D to 3D/Direct Depth Map" to enter the laboratory.

Now select menu: "Stereo".
A window is opened that allows you to evaluate a preview of your work in real time.
The preview can be freeviewed in crossed or parallel format.
By default the format is cross-eyed, to change it select "Graphics/Parallel View".

Simply click "<- to begin the work.

Draw in the window using mouse left-button, or right-button to undo the actions.

When dragged, the mouse leaves a grey trace , the intensity of the grey is proportional to the depth plane on which you are working.

Attention
A single “<-" click can leave a trace that is not visible.
This can depend on the brightness setting of your monitor.

All values in the depth map are relative, so it does not matter what the minimum value is.

If the value is high, the depth map is easier to view but the number of possible depth planes is reduced.

All independent applications can add or subtract to the minimum value in order to create a new reference.
If the trace does not become visible, apply as many "<- " clicks as necessary to make the trace visible.

An example of a directly-created Depth Map is shown below.
The left window shows the work in progress and the right window shows a stereo preview in cross-eyed format.

With this procedure you convert normal images or sketches into a depth map.

To use this method, it is necessary to open the image to convert before accessing the "Direct Depth Map" LAB.

Note

The precision that it is possible to get with this type of conversions is very limited compared to "Direct Anaglyph" or "Direct Stereo Pairs."
The problem has already been described and derives from the fact that the visibility of a Depth Map is very restricted and does not allow appraisal of small depth differences.
You are therefore recommended to only use it for the conversion of simple objects.

Nevertheless, all possible means to improve the depth manipulations have been implemented in this LAB.

All your work is relative to the reference cursor that is overlaid on the source image.

The conversion technique is identical to that of the other LAB's for which it is an opportune time to consult the "Direct Anaglyph" tutorial before beginning work.

To verify the work done at the depth level, press "Z".

Alternatively, pressing "Stereo" displays a realtime preview in crosseyed/parallel format.
To return to displaying the reference image, press "Image".

With this method you can modify an existing Depth Maps created in 3D Gugle or produced by other applications.
It is first necessary to open the Depth Map to be modified as an image in 3D Gugle.

When open "Direct Depth Map" LAB, click "Stereo".
This activates a stereo preview in cross-eyed format.

Now select”Graphics/Convert Depth Map to Stereo".
When this menu is selected, a new dialogue appears that allows you to set the conversion parameters.

The conversion function is very powerful and uses an algorithm unique to 3D Gugle.

At the same time as the depth map is converted, a stereo-pair preview is also created.
The stereo pairs so created allow you to verify (by freeviewing cross-eyed or parallel) in real time the result and accordingly you can adjust the 3D to your requirements.

On pressing the OK button, the Depth Map is memorised and is ready to be corrected or modified by your mouse.
The editing technique is identical to that already described for the creation of a new Depth Map.

To move between the levels use the Shift method ,as described here.

Note
To convert a Depth-Map it is necessary that the Depth-Map image has a free space (black colour) to the right.
To resize a Depth-Map use "Resize Canvas".

As previously explained, a Depth Map contains numerical data but it is also an ordinary image and as an image it can be processed with all the usual functions.
Different graphic functions produce different 3D effects.

In the chart that follows the main functions that can be used and their effect is listed, you are reminded that the graphic functions are simultaneously applied to all the colours.

Function	Scope	Result
Add Color	Adds or subtracts a constant value	Move the depth of the working point
Contrast	Increases the high value and decreases the low value, or the opposite	Add shadow and exaggerate the depth jumps
Blur	Filter "cut off" the height value	Add shadow and smooth the depth jumps
Sharpen	Increase the height value	Increase the the edge slope