切换到宽版
  • 广告投放
  • 稿件投递
  • 繁體中文
    • 14352阅读
    • 0回复

    [转载]FRED运用:Arizona眼睛模型 [复制链接]

    上一主题 下一主题
    离线xunjigd
     
    发帖
    952
    光币
    9
    光券
    0
    只看楼主 倒序阅读 楼主  发表于: 2016-02-24
    简介  jPC[_g  
    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。 b IH;  
    CWf / H)~  
    模型 \@-@Y  
    xqXo0  
    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。 *w$W2I>b7  
    (ScxLf=]  
    Table 1. AZ眼睛模型的定义
    !ds"9w  
    在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. /Y*WBTV'  
    1da@3xaF  
    光源 JBD7h5|Lc  
    _geWE0 E  
    多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 A]y`7jJ  
    'QG xd!4  
    _G_Cj{w  
    图1. 光源和提示信息使用
    ".f ;+wH  
    除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 *xc_k"\  
    T`/AY?#  
    在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 ylUb9KusOx  
    {qDSPo  
    图2. 字母F光源的设定方法光 he#J|p  
    |D'4uN8\  
    图3. 字母F在视网膜上位置点列图
    f'8kish  
    视网膜的散射 7t3X)Ah  
    h}-3\8 >  
    在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 +O'3|M  
    "B8Q:  
    -_ I _W&  
    图4. 视网膜朗伯散射设定
    3sc+3-TF  
    注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 c@YI;HS_g  
    "-y-iJ  
    Ulhk$CPA  
    图5. 视网膜重点采样规格设定
    k2E0/ @f{k  
    脚本 "vA}FV%tRq  
    s.EI`*xylY  
    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: O[# 27_dH  
    M-\Y"]sW  
    图6. 用户对话框的创建与编辑
    nvca."5y  
    图7. 用户对话框编辑器
    S(QpM.9*  
    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。 Yi .u"sh]  
    余下的脚本计算与屈光度有关的所有参数。 WJ)z6m]  
    M]<?k]_p  
    分析 U -Y03  
    \ Fl+\?~D  
    屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 M=.:,wRm  
    <wZQc  
    图7. 字母F在视网膜上颜色分析
    !P ~_Dl2d  
    脚本代码 V=)_yIS  
    3WN`y8l  
    Option Explicit     'Remove this to enable non-dimensioned variables to be used. k- Q%.o  
    z+ s6)Ad  
    Dim entity As T_ENTITY hZ[E7=NTQ^  
    Dim op As T_OPERATION Yv hA_v  
    Dim mat As T_MODELMATERIAL UYFwS/ RW}  
    Dim A As Double U0=]  
    Dim pupilDiam As Double  rL/H2[d  
    Dim eID As Long r/& sub"X  
    Dim parID As Long uC.K<jD%  
    Dim count As Integer 2#o>Z4 r{  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double D@G\7 KH@  
    Dim tlens As Double, nlens As Double `J]fcE%T0R  
    Dim curv As Double, conic As Double S2n39 3  
    Dim ok As Long .id)VF-l  
    +U_=*"@|  
    Sub Main El<]b7  
    R,)}>X|<  
        '用户输入对话框 8iW;y2qF  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 7:A x(El  
            TextBox 220,21,40,21,.TextBox1 'default: 0 u83J@nDQ  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 M@h|bN  
            OKButton 40,91,90,21 e'~Zo9`r6  
            CancelButton 190,91,90,21 m#ZO`W  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 +$X#q8j06  
            TextBox 220,49,40,21,.TextBox2 'default: 4 . 7zK@6i  
        End Dialog ~jK{ ,$:=  
        Dim dlg As UserDialog )=\# UE+W  
    "8'@3$>R=  
        ok = Dialog (dlg) ]DZE%  
    U;bK!&Z  
        If ok=0 Then    'cancel button was pressed y+!+ D[x  
            Print "Execution cancelled." iY`%SmB  
            End )v]/B+  
        End If RZ6xdq}>  
    N+zKr/  
        'Assign accommodation and pupil diameter & use defaults if field left empty ;WgJ<&33  
        If dlg.TextBox1 = "" Then t^`O{m<  
            A = 0           'Default accommodation DKfE.p)  
        Else *"WDb|PBb  
            A = CDbl(dlg.TextBox1) cKN$ =gd  
        End If |_}2f  
    Kh(ZU^{n  
        If dlg.TextBox2 = "" Then D,;\o7V  
            pupilDiam = 4   'Default pupil diameter !E,A7s  
        Else mK[)mC _8  
            pupilDiam = CDbl(dlg.TextBox2) 994` ua+  
        End If M(RZ/x  
    ` L >  
        Print " " <WjF*x p  
        Print "Accommodation = " & A & " Diopters" hj  
        Print "Pupil Diameter = " & pupilDiam & " mm" o[v\|Q`d  
    $KUo s+%  
        ' Calculate new parameters with accommodation z?[r  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness Dw=gs{8D  
    6&DX] [G  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens $B kubWM  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens ^M%uV  
    ; l&4V  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens `Q+ (LBP  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens I#m-g-J  
    LVc4CE f  
        tlens = 3.767 + 0.04*A                  'Lens thickness *5 |)-E  
    )'/|)  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Rp*R:3 C  
    YFE&r  
        'Adjust parameters to account for accommodation @ U kr  
    #Y0-BYa^  
        '************************************************************************* rEHkw '  
        'Aqueous thickness (Position of Lens) !FA# K8  
        '************************************************************************* o }3uo6GIB  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) B.g[c97  
        GetCustomElement eID, entity s <   
    +j(d| L\  
        parID = FindFullName( "Geometry.Arizona Eye" ) "Vw m  
    ?pYKZg /c  
        ' Delete any shift(s) in z *+TH#EL2  
        count = 0 nl(WJKq'  
        While GetOperationCount(eID)>count )+6v  
            GetOperation eID, count, op :ml2.vP  
            If op.Type="ShiftZ" Then G P:FSprP  
                DeleteOperation eID,count 89n:)|rWq  
                count=count-1 `W dD8E  
            End If CbPuoOl  
            count=count+1 %FS$zOsgGK  
        Wend N=5)fe%{4  
    >$ NDv  
        'Set new shift in 2pzF5h  
        op.Type = "ShiftZ"  %VzKqh  
        op.val1 = taq \A#1y\ok  
        op.parent = parID HDda@Jy  
        AddOperation eID, op fwrJ!j  
        Print "Set aqueous humor thickness = " & taq-0.55 -zp0S*iP7  
    -+7uy.@cS  
        '************************************************************************* A a= u+  
        'Radius and conic constant of anterior lens y" 6y!  
        '************************************************************************* 7_.11$E=H  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) RlqQ  
        GetConic eID, entity, curv, conic -b9;5eS!  
    UPc<gB  
        SetConic eID, entity, 1/Rant, CCant M t*6}Cl  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant /,MJq#@K  
    zaFt*~@X  
        '************************************************************************* Kx. X7R  
        'Radius and conic constant of posterior lens .s<*'B7&  
        '************************************************************************* 9Ro6fjjE  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) yfj K2  
        GetConic eID, entity, curv, conic y kW [B  
    j:}J}P  
        SetConic eID, entity, 1/Rpost, CCpost `%E8-]{uS  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost cooUE<a  
    s0*0 'f  
        '************************************************************************* EyI}{6~F  
        'Lens thickness (Position of posterior lens surface) cXR1grz  
        '************************************************************************* rwniOQe  
    ~`GhS<D  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) LAP6U.m'd  
    ?_oF:*~\  
        ' Delete any z-shift(s) Dy]I8_  
        count = 0 ~%/Wupf  
        While GetOperationCount(eID)>count m6MO W&  
            GetOperation eID, count, op RP 2_l$  
            If op.Type="ShiftZ" Then .MVYB\6Q0  
                DeleteOperation eID,count 6vp *9  
                count=count-1 8>7RxSF  
            End If +B'8|5tPX  
            count=count+1 g ^!C  
        Wend 7_wJpTz  
    65oWD-  
        'Set new z-shift ]Ni;w]KE  
        op.Type = "ShiftZ" Nrah;i+H\o  
        op.val1 = tlens !Oj)B1gc6&  
        op.parent = parID Z2Zq'3*  
        AddOperation eID, op k-E{d04-2  
        Print "Set lens thickness = " & tlens "c(Sysl.L  
    TgTnqR@/  
        '************************************************************************* f`8OM}un&  
        'Lens index of refraction F( Ak  
        '************************************************************************* j}F-Xs+  
        eID = FindMaterial( "Lens" ) v[TYc:L=  
        GetModelMaterial eID, mat ?sBh=Ds  
    dl5=q\1=  
        mat.Nd = nlens \ A%eG&  
        SetModelMaterial eID, mat ckjrk  
        Print "Set lens index of refraction = " & nlens 7l."b$U4yv  
    z305{B:Y  
        '************************************************************************* :s-o0$PlJ  
        'Pupil diameter DY{cQb  
        '************************************************************************* nRb^<cZf  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) wNNB;n` l  
    )9B:wc"  
        'Adjust pupil diameter (trimming volume inner hole) v)f7};"z   
    /ahNnCtu?1  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 1|ZhPsD.}g  
    3L _I[T$s  
        ' Adjust pupil location to just in front of the lens LF?P> 1%-  
        parID = FindFullName( "Geometry.Arizona Eye" ) ?-OPX_i_  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 4KI [D{  
        count = 0 _Mc>W0'5@  
        While GetOperationCount(eID)>count y/? &pKH^  
            GetOperation eID, count, op m7=1%6FN3  
            If op.Type="ShiftZ" Then NQ|xM"MqD  
                DeleteOperation eID,count 3Z>YV]YbeU  
                count=count-1 2X88:  
            End If |<`.fOxJP  
            count=count+1 maSgRf[g  
        Wend -$<O\5cAQ  
        op.Type = "ShiftZ" (QB+%2v  
        op.val1 = taq-0.01 J$9:jE-4  
        op.parent = parID h?UVDzI!O  
        AddOperation eID, op hzY[ G :  
    G",.,Px  
        Print "Set pupil diameter = " & pupilDiam yg;_.4TpIO  
    Y\+KoR' ;  
        'Update AZ Eye subassembly Description R4e&^tI@*  
        eID = FindFullName( "Geometry.Arizona Eye" ) PoShQR<  
        GetEntity eID, entity p" `%  
        entity.Description = "Accommodation = " & A & "D"  >0Ev#cX4  
        SetEntity eID, entity C+K=[   
    e kQrW%\3  
        Update % *z-PT22  
        Print "DONE!" DB`QsiC)  
         ~^N]y b  
    End Sub b^`AJK  
    kII7z;<^`  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: :Dl% _l  
    WW "i  
    Accommodation = 4 Diopters .~=HgOJ  
    Pupil Diameter = 4 mm $v} <'  
    Set aqueous humor thickness = 2.81 fP%Fyg^k  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 :DkAQ-<~  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 _qWC4NMF(  
    Set lens thickness = 3.927 hPdx(E)8!d  
    Set lens index of refraction = 1.42672 zPZF|%|  
    Set pupil diameter = 4 0y %L-:/c|  
    DONE! 8NimZ(  
    8 #oR/Nt  
    (文章来源:讯技光电)
     
    分享到