Scanning best practices - Revision history

Vrbovska: /* Scanning area */

2019-11-08T08:46:55Z

‎Scanning area

Admin: Example of transparent objects

2018-08-14T14:26:46Z

Example of transparent objects

Marcel: /* Introduction */

2017-05-16T07:27:35Z

‎Introduction

Marcel: reorganized page

2017-05-15T15:45:54Z

reorganized page

Marcel: /* Basics */

2017-05-12T08:35:46Z

‎Basics

Marcel: /* Choose the suitable scanner size */

2017-05-12T08:34:46Z

‎Choose the suitable scanner size

Marcel: /* Choose the suitable scanner size */ added image

2017-05-11T15:29:06Z

‎Choose the suitable scanner size: added image

Marcel: /* How to configure the scanner to provide the best quality */

2017-05-11T15:26:04Z

‎How to configure the scanner to provide the best quality

Admin at 11:23, 24 August 2016

2016-08-24T11:23:58Z

Admin at 11:00, 24 August 2016

2016-08-24T11:00:59Z

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 ==== Scanning area ====
 For bin picking applications, the ratio of the size of the object to the box size should not exceed 1:15. For example in the europallete sized box (1200 by 800 mm) it is reasonable to scan objects with minimal size 100 mm.
 === Distance ===

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 ==== Transparent objects ====
 It is not possible to scan transparent materials such as glass, ice or water . Remove such materials from the scene to avoid artifacts.  A thin layer of plastic wrap would still allow the wrapped object to be scanned with the risk of greater noise. It might also increase the glossiness of the object (see previous paragraph). Scanning through a window is possible as long as the window does not cause reflection — the angle between projector unit and window should be close to a right angle.
 ==== Translucent objects ====
 It is possible to scan translucent objects to some extent. Scattering of the light inside the material might cause the object surface to be scanned with a lower precision. For materials of  a high degree of translucency the same applies as for the transparent objects.

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 The output from the scanner is a 3D point cloud of the object's surface as viewed from one viewpoint. The scene has to be static (not moving) during the projection phase.
-Standard output format for point clouds is [https://en.wikipedia.org/wiki/PLY_(file_format) Stanford PLY], which can be easily imported in most 3D viewers or used by programmers.
+Standard output format for point clouds is [https://en.wikipedia.org/wiki/PLY_(file_format) Stanford PLY], which can be easily imported into most 3D viewers or used by programmers.
 == PhoXi Control Application ==

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-== Basics ==
+Photoneo 3D scanners work on the principle of '''[https://en.wikipedia.org/wiki/Structured_light structured light projection]''', which is an optical method of shape acquisition. For broader context, see following image:
 === Choose the right scanner size ===
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 For bin picking applications, the ratio of the size of the object to the box size should not exceed 1:15. For example in the europallete sized box (1200 by 800 mm) it is reasonable to scan objects with minimal size 100 mm.
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 To evaluate the distance of the scanned object, trigger the scan in PhoXi Control Application and then switch the view to Depth Map. The distance of the point from the camera is shown in the right panel when moving the mouse cursor over the point (pixel).
-=== Material albedo (reflectivity) ===
+=== Light conditions ===
-A material with higher [[Albedo|albedo]] provides a better signal-to-noise ratio.
-=== Strong ambient light ===
+==== Reflectivity (albedo) ====
-Indoor [[ambient light]] generally does not influence the scan. However, very strong light such as direct sun might be a problem. This occurs especially when scanning outdoors. Try to remove all sun illumination e.g. by shadowing the window, or by moving into a different place.
+A material with higher [[Albedo|albedo]] provides a better signal-to-noise ratio, resulting in higher scan quality. Very dark materials requires longer exposure and might have higher level of noise.
-=== Reflections ===
+==== Reflections ====
 Generally, non-glossy, matte materials are scanned without problem. Even soft-gloss objects have a nearly optimal scan. However, any specular reflections might influence the scan quality since the projected light is reflected out of the sight of the camera (in which case that part has a poor quality), or when reflected into other parts of the scene, reflected light interferes with scanning (in which case the part illuminated by reflection has artifacts). Especially metal with high-gloss finish (mirror-like) is problematic.
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 To further increase change of optimal scan while scanning glossy materials, use the “Scan glossy / Scan on sunlight” setting. Using this setting will increase the scanning time.
-=== Transparent objects ===
+==== Transparent objects ====
 It is not possible to scan transparent materials such as glass, ice or water . Remove such materials from the scene to avoid artifacts.  A thin layer of plastic wrap would still allow the wrapped object to be scanned with the risk of greater noise. It might also increase the glossiness of the object (see previous paragraph). Scanning through a window is possible as long as the window does not cause reflection — the angle between projector unit and window should be close to a right angle.
-=== Translucent objects ===
+==== Translucent objects ====
 It is possible to scan translucent objects to some extent. Scattering of the light inside the material might cause the object surface to be scanned with a lower precision. For materials of  a high degree of translucency the same applies as for the transparent objects.

← Older revision		Revision as of 08:35, 12 May 2017
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	The level of detail and accuracy of the scanner is described in datasheet as '''point size''', '''absolute accuracy''' and '''Z noise''' ([[PhoXi 3D scanners family#Specification Parameters Explanation\|See the explanation of these parameters]]).		The level of detail and accuracy of the scanner is described in datasheet as '''point size''', '''absolute accuracy''' and '''Z noise''' ([[PhoXi 3D scanners family#Specification Parameters Explanation\|See the explanation of these parameters]]).
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	==== Scanning area ====		==== Scanning area ====

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 == Basics ==
-=== Choose the suitable scanner size ===
+=== Choose the right scanner size ===
 Answer the questions
 * What is the required level of detail?
 * How big is the scanning area?
 Every PhoXi 3D scanner has the resolution of 3.2 million points. Imagine this as 3 million points arranged in a grid that will cover the surface of scanned object. The density of the points decreases with the distance of the scanner from the object. For illustration, see the density of the points on the table-tennis ball scanned with model L (from the distance 1,5 m) and model S (from the distance 0.5 m).
 [[File:Table-tennis-ball-scan-S-vs-L-w800.png]]
 == How to configure the scanner to provide the best quality ==

← Older revision		Revision as of 15:29, 11 May 2017
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	Every PhoXi 3D scanner has the resolution of 3.2 million points. Imagine this as 3 million points arranged in a grid that will cover the surface of scanned object. The density of the points decreases with the distance of the scanner from the object. For illustration, see the density of the points on the table-tennis ball scanned with model L (from the distance 1,5 m) and model S (from the distance 0.5 m).		Every PhoXi 3D scanner has the resolution of 3.2 million points. Imagine this as 3 million points arranged in a grid that will cover the surface of scanned object. The density of the points decreases with the distance of the scanner from the object. For illustration, see the density of the points on the table-tennis ball scanned with model L (from the distance 1,5 m) and model S (from the distance 0.5 m).

		+	[[File:Table-tennis-ball-scan-S-vs-L-w800.png]]

	== How to configure the scanner to provide the best quality ==		== How to configure the scanner to provide the best quality ==

← Older revision		Revision as of 11:00, 24 August 2016
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	The quality of the scan depends on multiple factors. The scanner provides a variety of settings to enable an optimal scan; however, even by rearranging the positions of the scene and scanner you can get better results. Always arrange the scene to have the best conditions for scan first and only then manipulate the settings of the scanner.		The quality of the scan depends on multiple factors. The scanner provides a variety of settings to enable an optimal scan; however, even by rearranging the positions of the scene and scanner you can get better results. Always arrange the scene to have the best conditions for scan first and only then manipulate the settings of the scanner.
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	=== Distance ===		=== Distance ===