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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 ^)|tf\4  
    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。 'r-B%D=  
    qkC{IBN92  
    模型 auY?Cj'"fs  
    =W"T=p*j  
    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。 eE\T,u5:  
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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. :qShP3^  
    <@4V G  
    光源 j~9Y0jz_  
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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。 OP_\V8=  
    o(D_ /]'8  
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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。 ]'>jw#|h  
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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。 :r:x|[3.  
    m5P@F@  
    图2. 字母F光源的设定方法光 \t&8J+%  
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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 !SLfAFcS  
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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。 ;xai JJK{  
    Vy=+G~  
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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。 ys7 Tq+  
    2@N-#x '  
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    图5. 视网膜重点采样规格设定
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    脚本 ]\ZmK0q<:  
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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: "b)EH/ s  
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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。 z\WyL;  
    余下的脚本计算与屈光度有关的所有参数。 N6*FlG-  
    Tj6Czq=*%T  
    分析 T w1&<S  
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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。 <J}JYT  
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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 YYe=E,q  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. ^i@0P}K<  
    , $cpm=1  
    Dim entity As T_ENTITY D'UIxc8  
    Dim op As T_OPERATION _]0<G8|Rv  
    Dim mat As T_MODELMATERIAL L/N%ft]!T  
    Dim A As Double y (%y'xBP  
    Dim pupilDiam As Double &}#zG5eu  
    Dim eID As Long v*OT[l7  
    Dim parID As Long +Je%8jH  
    Dim count As Integer < 7*9b  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double *c(YlfeZ#  
    Dim tlens As Double, nlens As Double $?;)uoAg  
    Dim curv As Double, conic As Double A5s;<d0  
    Dim ok As Long pMf ?'l  
    >5 2%^ ?  
    Sub Main r\C"Fx^  
    gA]3h8%w  
        '用户输入对话框 ?lU(FK  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 !2.eJ)G  
            TextBox 220,21,40,21,.TextBox1 'default: 0 wOEc~WOd  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 /.t1Ow  
            OKButton 40,91,90,21 Y/L*0 M.<  
            CancelButton 190,91,90,21 EO/41O  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 {s:"mkR  
            TextBox 220,49,40,21,.TextBox2 'default: 4 o"p['m*g  
        End Dialog py wc~dWvz  
        Dim dlg As UserDialog |[)pQGw  
    L=I;0Ip9y  
        ok = Dialog (dlg) 79+i4(H  
    Ir Y\Q)  
        If ok=0 Then    'cancel button was pressed Ns\};j?TU*  
            Print "Execution cancelled." }LoMS<O-[  
            End Qs<L$"L1  
        End If NLt"yD3t  
    `~N jBtQ  
        'Assign accommodation and pupil diameter & use defaults if field left empty d@ ] N  
        If dlg.TextBox1 = "" Then -\25&m!+  
            A = 0           'Default accommodation p& Kfy~  
        Else C4 -y%W"P  
            A = CDbl(dlg.TextBox1) qXoq< |  
        End If VU+=b+B~m  
    MieO1l  
        If dlg.TextBox2 = "" Then CF : !  
            pupilDiam = 4   'Default pupil diameter G(bl)p^  
        Else nx%eq ,Pq  
            pupilDiam = CDbl(dlg.TextBox2) TQQh:y  
        End If Fx:4d$>;  
    6A ptq  
        Print " " Rt@O@oDI  
        Print "Accommodation = " & A & " Diopters"  *qFl&*h}  
        Print "Pupil Diameter = " & pupilDiam & " mm" y=AF EP  
    N7_(,Gu*R  
        ' Calculate new parameters with accommodation j_z@VT}y  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness 4,BJK`{  
    VeOM `jy  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens B) dG:~  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 8= g~+<A  
    & s:\t L  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ;s+3 #Py  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens Qm_;o(  
    .fS{j$  
        tlens = 3.767 + 0.04*A                  'Lens thickness `$3ktQ$  
    v<mSd2B*  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 59~mr:*sF  
    J'yCVb)V  
        'Adjust parameters to account for accommodation F6"s&3D{  
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        '************************************************************************* aq#F  
        'Aqueous thickness (Position of Lens) e{^^u$C1.e  
        '************************************************************************* -vc ,O77z"  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) e7plL^^`  
        GetCustomElement eID, entity FRXaPod  
    w}e_ 17A  
        parID = FindFullName( "Geometry.Arizona Eye" ) 86a,J3C[  
    3\cx(  
        ' Delete any shift(s) in z { _Y'%Ggh  
        count = 0 cg9*+]rc  
        While GetOperationCount(eID)>count *w}r:04F  
            GetOperation eID, count, op }ktK*4<k  
            If op.Type="ShiftZ" Then 9_ ~9?5PU  
                DeleteOperation eID,count N0N%~3  
                count=count-1 qx*N-,M%k(  
            End If 9Q\RCl_1  
            count=count+1 hf;S#.k  
        Wend sejT] rJ  
    kYR ^  
        'Set new shift in N,:G5WxW  
        op.Type = "ShiftZ" nswhYSX  
        op.val1 = taq 1K'cT\aFm  
        op.parent = parID nGur2}>n  
        AddOperation eID, op PfGiJ]:V-u  
        Print "Set aqueous humor thickness = " & taq-0.55 P/Y)Yx_(  
    A$L:,b(  
        '************************************************************************* x'SIHV4M@Q  
        'Radius and conic constant of anterior lens !(3[z>  
        '************************************************************************* lA`-"  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) n#B}p*G  
        GetConic eID, entity, curv, conic V}Oz!  O  
    *z0 R f;  
        SetConic eID, entity, 1/Rant, CCant 6z'0fi|EN  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant WcpH= "vm  
    Nz%pl!  
        '************************************************************************* LvU/,.$  
        'Radius and conic constant of posterior lens @moaa}1  
        '************************************************************************* xn)F(P 0kv  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) vG=Pi'4XXo  
        GetConic eID, entity, curv, conic )Lk2tvr  
    ,mz7!c9H^a  
        SetConic eID, entity, 1/Rpost, CCpost #Yy5@A}`o  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost eKU4"XTk  
    z]=Ks_7  
        '*************************************************************************  UF@.  
        'Lens thickness (Position of posterior lens surface) jwI1 I{x  
        '************************************************************************* v "[<pFj^  
    579 t^"ja~  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Y^|15ek  
    m |.0$+=  
        ' Delete any z-shift(s) [g{fz3 O6  
        count = 0 % 3fpIzm  
        While GetOperationCount(eID)>count B%o%%A8*g  
            GetOperation eID, count, op <,H/7Ba  
            If op.Type="ShiftZ" Then ~bis!(}p-  
                DeleteOperation eID,count v[?gM.SF  
                count=count-1 nFro#qx  
            End If {7v|\6@e3  
            count=count+1 rxZk!- t)L  
        Wend FRQkD%k  
    D>`{f4Y  
        'Set new z-shift %f(4jQ0I  
        op.Type = "ShiftZ" dkg+_V!  
        op.val1 = tlens 0XE(vc!  
        op.parent = parID ;#*.@Or@Ah  
        AddOperation eID, op t*Z-]P  
        Print "Set lens thickness = " & tlens A}3E)Qo=G  
    +LF=oM<  
        '************************************************************************* 7dlMDHp\Y  
        'Lens index of refraction n"R$b:  
        '************************************************************************* YYvX@f  
        eID = FindMaterial( "Lens" ) |@?='E?h  
        GetModelMaterial eID, mat "'>fTk_  
    :73T9/  
        mat.Nd = nlens dLf ;g}W  
        SetModelMaterial eID, mat r 2{7h>  
        Print "Set lens index of refraction = " & nlens `G>|g^6%i  
    =Hj3o_g-  
        '************************************************************************* EAF\ 7J*  
        'Pupil diameter t=[/L]!  
        '************************************************************************* =s S=  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 1o)<23q`)  
    U)z1RHP|z  
        'Adjust pupil diameter (trimming volume inner hole) lHu/pSu@k  
    M2.*]AL  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Z(J 1A x  
    Exat_ L'?  
        ' Adjust pupil location to just in front of the lens \`8F.oZ^)  
        parID = FindFullName( "Geometry.Arizona Eye" ) !'>#!S~h3  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) gUp9yV  
        count = 0 ^Je*k)COn  
        While GetOperationCount(eID)>count )F0Q2P1I  
            GetOperation eID, count, op U/7jK40  
            If op.Type="ShiftZ" Then A\ tBmL_s  
                DeleteOperation eID,count O [=W%2I!i  
                count=count-1 >PGsY[N  
            End If 0bGQO&s [  
            count=count+1 0BOL0<Wq  
        Wend V0gu0+u~R  
        op.Type = "ShiftZ" UZgrSX {  
        op.val1 = taq-0.01 zS?DXE  
        op.parent = parID {|e7^_ke  
        AddOperation eID, op ?1X7jn`,+  
    Zj nWbnW  
        Print "Set pupil diameter = " & pupilDiam V. o*`V  
    zaE!=-U  
        'Update AZ Eye subassembly Description AP?m,nd6  
        eID = FindFullName( "Geometry.Arizona Eye" ) /EvT%h?p  
        GetEntity eID, entity Q%t _Epe  
        entity.Description = "Accommodation = " & A & "D" \/r]Ra  
        SetEntity eID, entity 4 @9cO)m  
    <*p  
        Update [bN_0T.YI  
        Print "DONE!" eBe5H =I@  
         RLDu5  
    End Sub Ge76/T%{Q  
    |@)jS.Bn  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: h:vI:V[/X  
    ulk yP  
    Accommodation = 4 Diopters _Aw-{HE'  
    Pupil Diameter = 4 mm 1rh2!4)7  
    Set aqueous humor thickness = 2.81 QX9['B<  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 EFs\zWF  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 y$L&N0z  
    Set lens thickness = 3.927 {|Fn<&G  
    Set lens index of refraction = 1.42672 5)M#hx%]#  
    Set pupil diameter = 4 "+BuFhSLf  
    DONE! `iwGPG!  
    yIS&ZtBA  
    (文章来源:讯技光电)
     
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