TriDef Photo Transformer - Tutorials

Advanced Depth Map Settings

Training objectives

At the end of this tutorial you will be able to:

  • Adjust Search Radius
  • Adjust Search Tolerance
  • Adjust Source Blur
  • Adjust Bias X,Y

Depth Map Options

There are several options available to you which affect the way in which Photo Transformer turns Depth Data points into a Depth Map. You will find that different types of image require different types of settings to produce the best Depth Map from the fewest Depth Data points. These settings affect the entire image, so you have to seek a balance to get the best result.

All settings are found in Edit > Preferences > Depth. You can also leave these settings alone if you wish and just add a few more Depth Data and Transparent points to complete your Depth Map. This is the recommended approach for beginners. These settings become most useful when working with either larger image or slower machines, when having fewer points helps to keep Photo Transformer responsive.

Search Radius

Search Radius determines how much of the image around a Depth Data point is searched for potentially matching depth values. The smaller the Search Radius, the more Depth Data points you have to add to the image. A larger Search Radius can yield a more accurate Depth Map with fewer Depth Data points, but it takes longer to update the Depth Map. Whether a depth value in this area is added to the Depth Map depends on the Search Tolerance.

Search Tolerance

Search Tolerance determines which parts of the image in the Search Radius area around a Depth Data point qualify as a matching depth value. These matching points are then added to the Depth Map. If your image has quite high color contrast between adjacent objects at different depths, then you can make the Search Tolerance higher and use fewer Depth Data points. If your image has poor contrast between these objects you should use a lower Search Tolerance and add more Depth Data points.

Tip: Remember that Transparent Points are very useful in low contrast image.

Source Blur

Source Blur can be used to soften a grainy Depth Map and can eliminate high-contrast speckles which sometimes cause visible flaws in the Depth Map. It is a useful tool for visually complex image (patterned shirts, long grass, crowds), but can lead to loss of fine detail.

Bias XY

Bias X,Y helps to reduce noise outside the border of objects in an image. It is useful for noisy image where there is a lot happening in the background behind the main object . For example, in an image of a baseball player standing well in front of a crowd, the people are visually complex with lots of different colors, but they only require a single flat depth. Bias X,Y can help Photo Transformer to ignore the background immediately around the ball player to reduce the bleeding effect.

Adjusting Search Radius

  1. Open Tutorial4.TriDefPhoto

    This image was Depth Mapped at a Search Radius of 40 and a Tolerance of 40.

  2. Open the Depth Window (View menu), and the Preferences Window, Depth panel (Edit menu).

  3. In the Depth window, select the Source checkbox and drag the slider to 50.

  4. In the Preferences window, drag the Search Radius slider down to about 10, then click Apply.

    You will see a polka dot effect on the Depth Map which would need many more Depth Data points to correct.

    Lower Search Radius values are useful for precision in complex image.

  5. Drag the Search Radius slider up to 100, and click Apply.

  6. Return the Search Radius to 40 and click Apply.

    This is a good average setting and will do for most cases.

Adjusting Search Tolerance

  1. Drag the Tolerance slider down to about 10, then click Apply.

    See how lots of holes appear in the Depth Map? You would need to add several more Depth Data points to fill them if you used this setting.

    Low Tolerance settings are useful where your image is composed of complex objects (with poor contrast) overlapping each other at different depths, although you do need to add more Depth Data points.

  2. Drag the Tolerance slider up to about 200, then click Apply.

    The Depth Map becomes much less defined, particularly around the tyre. To correct this problem you would need to add a lot of Transparent points to stop the overflow.

    High Tolerance settings are useful where your image is composed of complex or noisy objects at the same depth, such as a highly patterned shirt.

  3. Return Tolerance to 40 and click Apply.

    This is a good average setting and will do for most cases.

Adjusting Source Blur

  1. Drag the Source Blur slider down to 0, then click Apply

    You will see some speckles and noise appear in the Depth Map (you may need to deselect the Source checkbox to see tihs clearly). You could correct these errors with more Depth Data points, but Source Blur does it for you.

    Low Source Blur settings are useful when your image are composed of well defined, highly contrasted and detailed objects.

  2. Drag the Source Blur slider up to 5, then click Apply.

    The speckles will disappear, but now there may be a loss of definition. This is because Photo Transformer can no longer 'see' some of the details in the image--they have been blurred out of existence--and it now would be difficult to Depth Map these features accurately even with a lot of Depth Data and Transparent points.

    High Source Blur settings are useful when your image are composed of objects which are visually noisy but have simple outlines.

  3. Return Source Blur to 2 and click Apply.

    This is a good average setting and will do for most cases, unless you are 'losing' important low contrast details. In that case, drop Source Blur to 1 or 0.

Adjusting Bias X,Y

  1. Click the Bias X,Y checkbox to clear it, then click Apply.

    You may see some small errors appear on the edges of objects. You could correct these by careful placement of extra Depth Data points right at the edge, but points so close to edges can cause extra spillage and more corrective action.

    It is better to not use Bias X,Y when your image is composed of simple shapes against a clear background, as this will allow you to Depth Map with fewer Depth Data points.

  2. Click the Bias X,Y checkbox to select it, then click Apply.

    The little edge errors have been corrected.

    Bias X,Y is a useful setting on most types of image. At worst, leaving it on will only require you to occasionally add a few extra Depth Data points.

Remember that these settings affect the entire image: you can't use high Tolerance for one half and low Tolerance for the other half.

This has only been a brief overview of each settings behavior in isolation. In practice, these settings can interact in quite complex ways, so give it a try and let experience be your guide.

The End

This concludes the current series of Photo Transformer tutorials. For more information on particular topics, review the main Help topics. As you become more familiar with the program, consider using the range of Keyboard Shortcuts available to speed up your work.