TracePro Tutorial Tissue Optics

Transcription

1 TracePro Tutorial Tissue Optics

2 Splitting the Screen To view the System Tree, select Window Split, then drag the mouse to the right to position the vertical splitter bar. Alternatively, you can place your mouse over the bar at the left, then click and drag. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 2

3 To create the human tissue model we will start by creating the epidermis layer. First, click on the Insert menu and select the Primitive Solid option. The Insert Primitive Solid dialog box will appear as shown. Enter the following Widths for this block of tissue, X=1, Y=1, and Z=.1, and click Insert. This should create the object shown to the right. If you did not create this object as shown re-enter the parameters as shown in the dialog box and click Modify until you are satisfied. Creating the Tissue Model Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 3

4 Renaming Objects and Understanding Surfaces To change the object name, click on the object in the system tree to highlight it as shown. You can now type in any name you desire. Type in the name Epidermis. Click on the + sign in front of the object name to open the System Tree and see the 6 surfaces that make up this object. Surfaces 0 through 5 represent the 6 sides of this solid object. Surface 1 is the front (the -z side) and Surface 0 is the back (the +z side) of the object. Surfaces 2 through 5 are the 4 lateral sides. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 4

5 Next, we need to insert the Near Dermis Layer. In the Insert Primitive Solid dialog box enter the Widths and Center Position as shown in the dialog box at right. Click Insert to create this object. Rename the object to Near Dermis Layer as before using standard Windows Explorer conventions. This results in another block with 6 surfaces. Adding the Next Tissue Layer Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 5

6 Next, we will insert the Mid Dermis Layer. In the Insert Primitive Solid dialog box enter the Widths, and Center Position as shown in the dialog box at right. Click Insert to create this object. Now rename the object to Mid Dermis Layer just like before using the standard Windows Explorer conventions. This results in 1 object with 6 surfaces Adding the Mid Dermis Layer Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 6

7 Next, we will insert the Deep Dermis Layer. In the Insert Primitive Solid dialog box enter the Width, Center Position as shown in the dialog box at right. Click Insert to create this object. Now rename the object to Deep Dermis Layer just like before using the standard Windows Explorer conventions. Adding the Deep Dermis Layer Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 7

8 Adding the Subcutaneous Layer Next, we will insert the Subcutaneous Layer. In the Insert Primitive Solid dialog box enter the Width, Center Position as shown in the dialog box at right. Click Insert to create this object. Rename the object to Subcutaneous Layer. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 8

9 In the Insert Primitive Solids dialog box, select the Sphere tab. Next enter a radius of.02 for the sphere and a center position of X=0, Y=.15 and Z=.3. Click Insert to create the bottom of the hair follicle. Rename the object to Hair Follicle. Creating the Hair Follicle Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 9

10 Select the Cylinder/Cone tab in the Insert Primitive Solids dialog box. Enter a radius of for the Major R and a base position of X=0, Y=.15 and Z=.26. Click Insert to create the cylindrical portion of the hair follicle. Creating the Hair Follicle Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 10

11 First, select the Boolean Unite toolbar button (OR select Edit Boolean > Intersect). Using the mouse, select the spherical part of the hair follicle, then select the cylindrical part to Unite them. These selections can be made in the System Tree or in the model view. For this model, it s easier to use the System Tree. After the Unite operation the two objects will be replaced by one, and the objects will be united in the model view as shown to the right. If you expand the Hair Follicle in the System Tree, the result of this Unite will be 1 object with 4 surfaces. Uniting the two Hair Follicle pieces Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 11

12 Stretching or Sweeping the Hair Follicle Expand the Hair Follicle object in the System Tree to see all four surfaces. Click on Surface 2 in the System Tree. Select Edit Surface>Sweep to Sweep this surface. Enter.2 for the distance parameter and -1 for the draft angle. Click Apply to sweep the object along its surface normal. The extended hair follicle should look as shown to the right. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 12

13 Revolving and extruding the Hair Follicle The Hair Follicle object in the system tree should now have five surfaces. Click on Surface 3 in the System Tree. Select Edit Surface>Revolve to revolve this surface. Enter Angle=5, Draft Angle=-2.5, Radius=9, Axis X = 1 and Click Calculate a Position using selected surface. This calculates the position to revolve the surface around. Click Revolve Surface to revolve the object around the calculated point. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 13

14 Select the Hair Follicle object in the System Tree. Right-click on the model view and the pop-up menu shown at right will appear. Select the Move option and the Move Selection dialog box appears Enter Y Center=-.5 and click Copy to make a 2nd hair follicle object below the first one. See the figure on the next page to check your work. To Create a Second Follicle Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 14

15 Completed geometry Your sample geometry should look as shown. This is a good time to save the file to disk. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 15

16 Creating bulk scatter material properties To define a bulk scatter property you must select Define Edit Property Data>Bulk Scatter Properties to open the bulk scatter property editor. This is where you enter the wavelength, anisotropy (g), and scattering coefficient (µ s ). The bulk scatter material for the deep dermis is shown here. It is defined for the 1.45, 1.67, 1.9 and 2.2 micrometer wavelengths. To create a bulk scatter property, first click the Add Bulk Scatter button. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 16

17 Creating a Bulk Scatter Property The Enter New Bulk Scatter Property dialog box will appear. Now enter the name of the bulk scatter property you want to create. For this example enter Deep Dermis. Enter in the Initial Wavelength box the first wavelength you want to define the property at in microns. Enter 1.45 and click OK. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 17

18 Do the same thing for the next 3 wavelengths by clicking on the Insert Wavelength button and entering the next three wavelengths. The figure shows the last dialog box entry for the 2.2 micron wavelength. Creating a Bulk Scatter Property Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 18

19 The Edit Enable option should be clicked so that you can enter data directly into the table Now mouse click into each portion of the table, anisotropy factor, g=.9 for all four wavelengths and enter the scatter coefficients of 3.96 for the 1.45 wavelength, 3.53, 3.16 and 2.85 respectively for the other three wavelengths. At the end of entering these values make sure you click the Save button on the toolbar to save the property. Creating a Bulk Scatter Property Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 19

20 If you have defined a bulk scatter property, you can import and export these properties ASCII format. This capability lets you share these properties with technical support and other users. To import and export properties select File Import Property. This File Menu option is only available when you are in a Property Editor as shown. Click on the Import or Export option to bring in or output a bulk scatter property. Importing Bulk Scatter Properties Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 20

21 Importing all other Bulk Scatter Properties All the bulk scatter properties you need for this tutorial should be in your TracePro database already. If they aren t, you can import them from the TracePro CD: The five bulk scatter properties you need are: Epidermis Mid Dermis Near Dermis Deep Dermis Subcutaneous Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 21

22 Click on the Epidermis object to highlight it in the System Tree and in the model view. Select Define Apply Properties to open the Apply Properties dialog box. Alternatively, you can right-click and select Properties from the popup menu. Select the Bulk Scattering tab and select the Epidermis property. Click Apply to apply this property to the highlighted Epidermis object. The bulk scatter property should be shown for the Epidermis object. Applying Bulk Scatter Properties Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 22

23 You will need to do apply bulk scatter properties to each of the Near Dermis, Mid Dermis, Deep Dermis, and the Subcutaneous objects. There is no bulk scatter property for the hair follicle, it is an absorber. You system should look similar to the system at right. Applying Bulk Scatter Properties Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 23

24 TracePro has a Material property database that defines the index of refraction and the volume absorption of the material as you ray trace through it. To define a material property you must select Define Edit Property Data>Material Properties. The material properties you need for this tutorial are included with TracePro, so you do not need to define them now. The material property for the deep dermis is shown defined to the left for the 1.45, 1.67, 1.9 and 2.2 micron wavelengths. Creating Material Properties Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 24

25 Click on the Near Dermis Layer object to highlight this object in the System Tree and in the model view. Select Define Apply Properties. The Apply Properties dialog box will appear. Select the Material tab, select the Tissue Catalog, then select the Near Dermis property. Click Apply to apply this property to the Near Dermis Layer object. The material property should be shown for the Near Dermis object. Applying Material Properties Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 25

26 You will need to do apply material properties to each of these objects: Epidermis, Near Dermis, Mid Dermis, Deep Dermis, and Subcutaneous. There is no material property for the hair follicle, it is an absorber. You system should look similar to the system at right after you apply material properties to each of the objects. Save your work. Applying Material Properties Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 26

27 Click on one of the Hair Follicle objects to highlight it in the system tree and in the model view. Select the Surface tab in in the Apply Properties dialog box and select the Perfect Absorber property. Click Apply to apply this property to the highlighted Hair Follicle object. This will apply the Perfect Absorber surface property to all member surfaces of the Hair Follicle object. The Perfect Absorber surface property should be shown for all surfaces of the Hair Follicle object. Repeat for the other hair follicle. Adding Surface Properties Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 27

28 Setting Raytrace Threshold Options Select Analysis RayTrace Options, select the Thresholds tab and set the Flux Threshold to 0.01 This means that ray segments whose flux falls below 1% of the starting flux are not traced after. Click the Apply button to set the flux threshold. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 28

29 To create a Grid of rays select Analysis Grid Raytrace to open Grid Raytrace dialog box. On the Grid Setup tab, enter a Grid Boundary Outer Radius of.001, Grid Pattern Rings of 3 and change the Origin to X=0, Y=0 and Z=-.1. Click Apply to set this information. Creating a Grid of Rays to Trace Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 29

30 Select the Beam Setup tab in the Grid Raytrace dialog box. Change the Angular Profile Half Angle Radius to 5. To begin the ray-trace click Apply & Trace Rays. TracePro will perform two steps. The audit step comes first, in which TracePro applies properties to each surface and object and then partitions the model into voxels. The Audit progress box is shown above. After the audit is completed the ray-trace will begin. Creating a Grid of Rays to Trace Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 30

31 The color of the ray signifies how much of the starting flux the ray carries. If the ray is red it has between 100 and 67% of its starting flux. If it is green it has between 67-33% of it starting energy. If blue it has less than 33% of its starting flux. In this model it is easy to see that the tissue is absorbing flux as rays propagate through the system. There is even Fresnel reflection at the very start, where light first interacts with the top layer of Epidermis tissue. You can see the bulk scattering occurring where the light is bending inside the tissue. Analyzing The Ray Trace View Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 31

32 Irradiance Options To view irradiance on a surface we must first set the options to view an irradiance map. Select Analysis Irradiance/Illumi nance Options to open the Irradiance Options dialog box. Set the Rays to Plot to Incident and the Color Map to Color(rainbow) on Black. Select Smoothing and Profiles and then click Apply. Click on the Epidermis object Surface 1 to select it for displaying the irradiance map. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 32

33 In TracePro, Irradiance/Illuminance Maps are used to view the spatial distribution of light. An irradiance/illuminance map calculation can be performed on any surface in the model. Select Analysis Irradiance/Illumin ance Map. We are interested in the spatial distribution of light on the Epidermis object surface 1. The irradiance map should show a small dot in the middle of the screen with different color radiating outwards Click anywhere on the dot to get cross-sectional profiles of the flux as shown. Irradiance map Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 33

34 We need to add an object that we are looking for with our instrument. Let s make it a very shiny object. We also need an object to receive the light from the reflecting rays. First we ll add the shiny object. Select Insert Menu Insert Primitive Solids. In the Insert Primitive Solids dialog box, select the Cylinder/Cone tab, enter Major R =.01, Length =.1 and the Base Position X = -.05 and Z =.3, Base Rotation Y = 90. Click Insert to insert the object. Modifying the system Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 34

35 Applying Surface Properties Change the name of the object to Fluid as you have done before. Right-click anywhere on the screen and select Properties from the popup menu to open the Apply Properties dialog box. Make sure the Fluid object is still selected. Select the Surface tab. Select the Perfect Mirror Property. Click Apply to apply the perfect mirror property. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 35

36 To create the detector object, open the Insert Primitive Solids dialog box again, and select the Block tab. Enter widths X, Y and Z =.02 and the Center Position X=0, Y=0.1, and Z= Click Insert to insert the object. Change the name of the object to Detector as you have done before. Create a Detector Object Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 36

37 Make sure the Detector object is still selected. In the Apply Properties dialog box, Surface tab, select the Perfect Absorber Property. Click Apply to apply the perfect mirror property. To get any rays to strike our detector, we need to trace a lot more rays. In the Analysis Grid Raytrace dialog box, Grid Setup tab, change the number of rings to 20 to trace 1141 rays. Click Apply and Trace Rays to begin the raytrace. Applying Surface Properties Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 37

38 Irradiance map on the detector object To see how much flux reached our detector we first have to select the surface that intersects reflecting rays. It happens to be surface 0, the front of the Detector object. Select this surface by clicking on it in the System Tree area. Click the irradiance map icon to see the map. Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 38

39 The Irradiance Map shows the total flux hitting this object. Open the Irradiance Options dialog box. Click Normalized Flux to see the percentage of flux reaching this surface. As you can see only 2 rays hit this surface. You will need to trace many more rays to get a good idea of the distribution for this system. You will need to change this in the Analysis Grid Raytrace options by increasing the number of rings. Irradiance Map for the Detector Copyright 2001 Lambda Research Corporation TracePro Tissue Optics Tutorial 39