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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 sV'v* 1|  
    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。 *8206[y  
    2f`xHI/@fj  
    模型 ji##$xC  
    3M$X:$b  
    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。 0Bu*g LY  
    .93S>U<_  
    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. FF@`+T  
    > Z++^YVE  
    光源 9}XT'+`y  
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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。 `5<1EGJsD  
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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。 iUCwKpb9  
    !5E9sk{)  
    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。 /Tcb\:`9  
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    图2. 字母F光源的设定方法光 O3&|}:<  
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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 9;pzzZ  
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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。 uOb2npPj  
    @?vLAsp\  
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    图4. 视网膜朗伯散射设定
    :@WLGK*u.  
    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。 &*ZC0V3  
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    图5. 视网膜重点采样规格设定
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    脚本 sM0c#YK?  
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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: bCt_y 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。 SCI1bMf  
    余下的脚本计算与屈光度有关的所有参数。 7Qt2gf  
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    分析 < )Alb\Z  
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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。 "u,sRbL  
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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  .?70=8{  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. "zXGp7Q'#  
    xdCs5ko  
    Dim entity As T_ENTITY .r(^h/IF  
    Dim op As T_OPERATION |zT%$  
    Dim mat As T_MODELMATERIAL R&#[6 r(h  
    Dim A As Double ~DK F%}E  
    Dim pupilDiam As Double [Yn;G7cK  
    Dim eID As Long jjYM3LQcdP  
    Dim parID As Long G^ K*+  
    Dim count As Integer 8>2&h  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double xp~YIeSg  
    Dim tlens As Double, nlens As Double .Dc28F~t  
    Dim curv As Double, conic As Double Th_Q owk  
    Dim ok As Long HUK" OH  
    8g-P_[>  
    Sub Main TS/Cp{  
    n#)PvV~  
        '用户输入对话框 7:#  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 5FZ47m ~{Z  
            TextBox 220,21,40,21,.TextBox1 'default: 0 ;gdi=>S_  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 (21']x  
            OKButton 40,91,90,21 `:V}1ioX5  
            CancelButton 190,91,90,21 r(pwOOx  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 :EYu 4Y  
            TextBox 220,49,40,21,.TextBox2 'default: 4 QCVsVG!sN  
        End Dialog Lf[G>0t&n  
        Dim dlg As UserDialog  bkxk i@t  
    .@fK;/OuC  
        ok = Dialog (dlg) U0!^m1U:  
    c6f|y_ 2  
        If ok=0 Then    'cancel button was pressed Zlr{L]c  
            Print "Execution cancelled." \nrgAC-b  
            End n9N#&Q"7m  
        End If \FIa,5k8  
    t1G1(F#&%  
        'Assign accommodation and pupil diameter & use defaults if field left empty @gH(/pFX  
        If dlg.TextBox1 = "" Then (zjz]@qJ  
            A = 0           'Default accommodation 1 ,#{X3  
        Else w/?nUp  
            A = CDbl(dlg.TextBox1) @TdQZZ}G\x  
        End If BhOXXa{B  
    R5m`;hF  
        If dlg.TextBox2 = "" Then )>-77\  
            pupilDiam = 4   'Default pupil diameter x-w`KFS  
        Else Lhl$w'r  
            pupilDiam = CDbl(dlg.TextBox2) JZW gr&O<  
        End If MF f05\aDu  
    'bZMh9|  
        Print " " V"w`!  
        Print "Accommodation = " & A & " Diopters"  $&ex\_W  
        Print "Pupil Diameter = " & pupilDiam & " mm" #;5[('&[  
    IXbdS9,>F  
        ' Calculate new parameters with accommodation nYI/&B{p  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness 4 *Bp  
    L 2[Ei|9_  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens fO[Rf_  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens |h#DL$  
    "Czz,;0  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens 73&]En  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens dE 3i=  
    X{5v?4wI  
        tlens = 3.767 + 0.04*A                  'Lens thickness ,[Dh2fPM,  
    k7:GS,7  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 1mT|o_K{ T  
    h5LJij J  
        'Adjust parameters to account for accommodation 0C lX  
    9\AEyaJFZ  
        '************************************************************************* 3X88x-3  
        'Aqueous thickness (Position of Lens) \e`6=Q%  
        '************************************************************************* 7xLo 4  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) se<i5JsSV  
        GetCustomElement eID, entity l-DGy#h+z  
    )ZS:gD  
        parID = FindFullName( "Geometry.Arizona Eye" ) g i1}5DR  
    *%ed;>6:Q  
        ' Delete any shift(s) in z ^2&O3s  
        count = 0 &*jxI[  
        While GetOperationCount(eID)>count 1?/5A|?V4+  
            GetOperation eID, count, op &,m'sQ  
            If op.Type="ShiftZ" Then +Fu@I{"A  
                DeleteOperation eID,count S(g<<Te  
                count=count-1 hN>('S-cq  
            End If  IgzCh  
            count=count+1 %f_)<NP9=  
        Wend .fio<mqi  
    o1fyNzq<  
        'Set new shift in ?c|`R1D  
        op.Type = "ShiftZ" 377j3dP  
        op.val1 = taq 1Y H4a|bc  
        op.parent = parID kr/1Dsr4  
        AddOperation eID, op ?=/}Ft  
        Print "Set aqueous humor thickness = " & taq-0.55 [oQ`HX1g  
    ~ERRp3Ee ?  
        '************************************************************************* ?:#>^eWYe7  
        'Radius and conic constant of anterior lens ]>VJ--fH  
        '************************************************************************* t7U,AQ=;P5  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) eZ8Y"i\!y  
        GetConic eID, entity, curv, conic EWu iaw.  
    ,wry u|7"$  
        SetConic eID, entity, 1/Rant, CCant o*O "\/pmF  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ?L<UOv7;t  
    <2o.,2?G  
        '************************************************************************* N=O+X~  
        'Radius and conic constant of posterior lens H#1*'e>  
        '************************************************************************* 4%',scn  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Xa?6#  
        GetConic eID, entity, curv, conic "6I-]:K-  
    !T#8N7J>  
        SetConic eID, entity, 1/Rpost, CCpost 9sfB+]}h  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost (/9.+V_  
    %#S"~)  
        '************************************************************************* h+zkVRyA  
        'Lens thickness (Position of posterior lens surface) S5*~r@8h  
        '************************************************************************* Z?.p%*>`T=  
    brYYuN|Vc  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) x8SM,2ud  
    wB1|r{  
        ' Delete any z-shift(s) }C`}wS3i  
        count = 0 3zA8pI w  
        While GetOperationCount(eID)>count ReHd~G9  
            GetOperation eID, count, op v)C:E9!|  
            If op.Type="ShiftZ" Then RF,=bOr19  
                DeleteOperation eID,count /QV. U.>G  
                count=count-1 |`q)/ 08b  
            End If Ads<-.R  
            count=count+1 G+ $)W u  
        Wend !"Oj$c -  
    5ykk11!p$  
        'Set new z-shift %/6e"o  
        op.Type = "ShiftZ" Gw\G+T?M-  
        op.val1 = tlens J1c&"Oh  
        op.parent = parID \ ]kb&Qw  
        AddOperation eID, op DiYJlD&  
        Print "Set lens thickness = " & tlens lE2wkY9^/  
    ~ ];6hxv  
        '************************************************************************* jnU*l\,  
        'Lens index of refraction iZkW+5(  
        '************************************************************************* .Kh(F 6 s  
        eID = FindMaterial( "Lens" ) H(%] Os  
        GetModelMaterial eID, mat }VGI Y>v  
    &, Zz  
        mat.Nd = nlens x^='pEt{  
        SetModelMaterial eID, mat ~*cY&  9  
        Print "Set lens index of refraction = " & nlens yqVaA 'w5  
    GmmT'3Q  
        '************************************************************************* P/gb+V=g!  
        'Pupil diameter @]ptY*   
        '************************************************************************* d4/`:?w  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) gGiV1jN _  
    v_@#hf3  
        'Adjust pupil diameter (trimming volume inner hole) YP\4XI  
    z)<pqN  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Q,,fDBN  
    RZ/+ K=  
        ' Adjust pupil location to just in front of the lens wsb=[$C  
        parID = FindFullName( "Geometry.Arizona Eye" ) Lm*LJ_+ B  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) "-j@GCme  
        count = 0 m[xf./@f{  
        While GetOperationCount(eID)>count U+RCQTo  
            GetOperation eID, count, op A^r [_dyZ  
            If op.Type="ShiftZ" Then /nMqEHCyg  
                DeleteOperation eID,count 7AtXG^lK  
                count=count-1 ^?^|Y?f2P?  
            End If HDW\S#  
            count=count+1 3]kAb`9[K2  
        Wend G$x["  
        op.Type = "ShiftZ" ` .sIZku  
        op.val1 = taq-0.01 TNyY60E  
        op.parent = parID Y^*$PED?  
        AddOperation eID, op ukDH@/  
    P #2TM  
        Print "Set pupil diameter = " & pupilDiam )oxP.K8q)U  
     _7j/[  
        'Update AZ Eye subassembly Description zk 'e6  
        eID = FindFullName( "Geometry.Arizona Eye" ) A^Hp#b @  
        GetEntity eID, entity "w|k\1D  
        entity.Description = "Accommodation = " & A & "D" BE2\?q-  
        SetEntity eID, entity a+a%}76N  
    z`r4edk3  
        Update z5*O@_r+.b  
        Print "DONE!" 4;c_%=cU  
         Ko]h r  
    End Sub ~tj7zI6  
    knK=ENf;e  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: p_40V%y^  
    ?xTeio44  
    Accommodation = 4 Diopters pYhI{  
    Pupil Diameter = 4 mm Bzy=@]`  
    Set aqueous humor thickness = 2.81 ]'ApOp  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 DwrCysIK  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 )RCqsFjK  
    Set lens thickness = 3.927 @Kb|  
    Set lens index of refraction = 1.42672 k;:u| s8NS  
    Set pupil diameter = 4 /h.3<HI."*  
    DONE! &qI5*aQ8T  
    T#^6u)  
    (文章来源:讯技光电)
     
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