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    [转载]FRED运用:Arizona眼睛模型 [复制链接]

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    离线xunjigd
     
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    只看楼主 倒序阅读 楼主  发表于: 2016-02-24
    简介 !#~KSO}zW2  
    人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 5*+DN U@  
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    模型 v9FR  
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    模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 X)6G :cD  
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    Table 1. AZ眼睛模型的定义
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    在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. :5$ErI  
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    光源 `"PHhCG+z  
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    多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 ](v,2(}=  
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    图1. 光源和提示信息使用
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    除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 6 rj iZ%  
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    在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 Q)BSngW+  
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    图2. 字母F光源的设定方法光 >N2kWSa  
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    图3. 字母F在视网膜上位置点列图
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    视网膜的散射 p`rjWpH  
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    在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 $] xH"Z%"  
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    图4. 视网膜朗伯散射设定
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    注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 y9]7LETv\M  
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    图5. 视网膜重点采样规格设定
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    脚本 \m}a%/  
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    内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: =OtW!vx#R.  
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    图6. 用户对话框的创建与编辑
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    图7. 用户对话框编辑器
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    如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 p/Q< VV  
    余下的脚本计算与屈光度有关的所有参数。 -T1R}ew*t  
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    分析 "%+||IyW  
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    屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 "~EAt$  
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    图7. 字母F在视网膜上颜色分析
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    脚本代码 \Gk}Fer  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. "Dk@-Ac  
    :|S[i('  
    Dim entity As T_ENTITY 1|-C(UW>  
    Dim op As T_OPERATION frm[<-~w0  
    Dim mat As T_MODELMATERIAL bZgo}`o%  
    Dim A As Double lul  
    Dim pupilDiam As Double ^`dMjeF  
    Dim eID As Long .pe.K3G &  
    Dim parID As Long m(:R(K(je  
    Dim count As Integer eYoc(bG(+  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ZVJ6 {DS/  
    Dim tlens As Double, nlens As Double CdCY#$Z  
    Dim curv As Double, conic As Double (zy|>u  
    Dim ok As Long g#l!b%$  
    I]5){Q" S  
    Sub Main }j1;0kb?  
    CE  
        '用户输入对话框 .Wp(@l'Hd  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 }*%=C!m4R!  
            TextBox 220,21,40,21,.TextBox1 'default: 0 C" `\[F`.k  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ^t<L  
            OKButton 40,91,90,21 ;,TT!vea  
            CancelButton 190,91,90,21 FMn|cO.vEP  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 E=S_1  
            TextBox 220,49,40,21,.TextBox2 'default: 4 [:e>FXV  
        End Dialog Ekrpg^3qp"  
        Dim dlg As UserDialog ]v@ng8  
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        ok = Dialog (dlg) 7KRNTnd  
    [a$1{[|)  
        If ok=0 Then    'cancel button was pressed L{&1w  
            Print "Execution cancelled." hHcevSr  
            End _}']h^@ Z  
        End If d/3&3>/  
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        'Assign accommodation and pupil diameter & use defaults if field left empty _f "I%QTL  
        If dlg.TextBox1 = "" Then v [x 5@$  
            A = 0           'Default accommodation n31nORx50  
        Else F{7 BY~d  
            A = CDbl(dlg.TextBox1) hhylsm  
        End If Ebi~gGo  
    ;9=4]YZt  
        If dlg.TextBox2 = "" Then P??pWzb6HH  
            pupilDiam = 4   'Default pupil diameter <>-gQ9  
        Else j9RpYz  
            pupilDiam = CDbl(dlg.TextBox2) F3Vvqt*2  
        End If 6~s{HI!  
    >B;S;_5=  
        Print " " \B/( H)Cd*  
        Print "Accommodation = " & A & " Diopters" EOqV5$+  
        Print "Pupil Diameter = " & pupilDiam & " mm" _Bn8i(  
    D,-L!P  
        ' Calculate new parameters with accommodation *x 2u  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness \4 t;{_  
    >i61+uzEd+  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens FEa%wS{  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens lu1T+@t  
    Ja\B%f  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens {=R vFA  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens X/Fip 0i  
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        tlens = 3.767 + 0.04*A                  'Lens thickness u<j.XPK  
    )In;nc  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction F>@z&a}(  
    S|@ Y !  
        'Adjust parameters to account for accommodation dwzk+@]8  
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        '************************************************************************* <sGioMr  
        'Aqueous thickness (Position of Lens) &j{I G`Trl  
        '************************************************************************* )@.ODW;`  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) wYHyVY2tj2  
        GetCustomElement eID, entity tE=$#  
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        parID = FindFullName( "Geometry.Arizona Eye" ) \nVoBW(  
    .8|5;!`WB  
        ' Delete any shift(s) in z <("P5@cExU  
        count = 0 ,?GAFg K:  
        While GetOperationCount(eID)>count  _8z  
            GetOperation eID, count, op hJJo+NNN  
            If op.Type="ShiftZ" Then ux7g%Q ^"  
                DeleteOperation eID,count KiNluGNt  
                count=count-1 kRzqgVr%  
            End If xoE,3Sn  
            count=count+1 +n8,=}  
        Wend LA837%)  
    90$`AMR  
        'Set new shift in E|B1h!!\c  
        op.Type = "ShiftZ" @eDL j}  
        op.val1 = taq 8ax3"G  
        op.parent = parID :OY7y`hRG  
        AddOperation eID, op Z:MU5(Te  
        Print "Set aqueous humor thickness = " & taq-0.55 K9'AYFse  
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        '************************************************************************* vnz}Pr! c  
        'Radius and conic constant of anterior lens v[?eL0Z  
        '************************************************************************* B;L^!sLP  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Aa%ks+1  
        GetConic eID, entity, curv, conic =G<S!qW  
    \V<deMb=  
        SetConic eID, entity, 1/Rant, CCant s0'Xihsw6  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant \6Hu&WHy  
    %G~%:uJ5  
        '************************************************************************* gB#$"mq,  
        'Radius and conic constant of posterior lens zd [cp@  
        '************************************************************************* TWQ{, B  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) V6 ,59  
        GetConic eID, entity, curv, conic r|7hm:F)  
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        SetConic eID, entity, 1/Rpost, CCpost iW <B1'dp  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Wv)2dD2I  
    j2{ '!  
        '************************************************************************* !Lj+&D|z  
        'Lens thickness (Position of posterior lens surface) 6~Xe$fP(  
        '************************************************************************* X?.LA7)CK  
    E)l@uPA'1  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) dCMWv~>  
    s|&2QG0'7  
        ' Delete any z-shift(s) *YY:JLe  
        count = 0 [mk!] r  
        While GetOperationCount(eID)>count }vdhk0  
            GetOperation eID, count, op ;-65~i0Iu  
            If op.Type="ShiftZ" Then %S4pkFR  
                DeleteOperation eID,count %7rWebd-  
                count=count-1 b$)XS  
            End If ^?tF'l`  
            count=count+1 +hS}msu'  
        Wend E>?T<!r~j  
    xpVYNS{c+|  
        'Set new z-shift enT.9|vm/  
        op.Type = "ShiftZ" P/FO,S-V  
        op.val1 = tlens jW+L0RkX  
        op.parent = parID L$FLQyDR  
        AddOperation eID, op cB7=4:U  
        Print "Set lens thickness = " & tlens Iih~rWJ  
    &wZ:$lK#o  
        '*************************************************************************  0$l D  
        'Lens index of refraction E8Wgm 8  
        '************************************************************************* s&$Zgf6Z  
        eID = FindMaterial( "Lens" ) %k3a34P@  
        GetModelMaterial eID, mat PV%7 m7=x  
    S\jN:o#b  
        mat.Nd = nlens &sQtS  
        SetModelMaterial eID, mat e&u HU8k*  
        Print "Set lens index of refraction = " & nlens Y&5h_3K;<  
    .HG0%Vp  
        '************************************************************************* l$Y7CIH  
        'Pupil diameter `7|v  
        '************************************************************************* KyAQzN9  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ZUMzWK5Th  
     _D(F[p|  
        'Adjust pupil diameter (trimming volume inner hole) w]\O3'0Js  
    #.%;U' #O  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Tl Z|E '_C  
    .)mw~3]  
        ' Adjust pupil location to just in front of the lens T;}pMRd%  
        parID = FindFullName( "Geometry.Arizona Eye" ) E7axINca  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) F/}PN1#T  
        count = 0 DP*[t8  
        While GetOperationCount(eID)>count W$P)fPU'  
            GetOperation eID, count, op nK6{_Y>  
            If op.Type="ShiftZ" Then j4Cad  
                DeleteOperation eID,count  $3%EKi  
                count=count-1 -q\1Tlc]3  
            End If !UlG! 820  
            count=count+1 e?G] fz  
        Wend hM(|d@)  
        op.Type = "ShiftZ" dd>stp   
        op.val1 = taq-0.01 z/N~HSh!d  
        op.parent = parID ueYZM<],  
        AddOperation eID, op Xi1/wbC  
    '8wA+N6Zr7  
        Print "Set pupil diameter = " & pupilDiam nYMdYt04sl  
    B}YB%P_CWs  
        'Update AZ Eye subassembly Description l>S~)FNwXJ  
        eID = FindFullName( "Geometry.Arizona Eye" ) >e"CpbZ'  
        GetEntity eID, entity -2mm 5E~N  
        entity.Description = "Accommodation = " & A & "D" X%S?o  
        SetEntity eID, entity i}+K;,Da:8  
    H{`S/>)[   
        Update <`a!%_LC [  
        Print "DONE!" grnlJ=  
         qv=i eU  
    End Sub Z@ * ^4Ve  
    6<R!`N 6  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: {KE858  
    =\?KC)F*e  
    Accommodation = 4 Diopters e&E""ye  
    Pupil Diameter = 4 mm U*=ebZno  
    Set aqueous humor thickness = 2.81 W :jC2,s!m  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 -D0kp~AO4N  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 a}+|2k_  
    Set lens thickness = 3.927 F%t`dz!L  
    Set lens index of refraction = 1.42672 _CBG?  
    Set pupil diameter = 4 *)ZDN~z7o  
    DONE! R-"A* /A 2  
    :}v&TQ  
    (文章来源:讯技光电)
     
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