[技术]RPC Photonics扩散片BSDF [复制链接]

摘要： (V#5Cs,o:  
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RPC Photonics公司有高品质的的工程漫射体BSDF测试数据，但它对于FRED帮助甚少，下面这个步骤描述了如何利用FRED脚本转换RPC Photonics提供的TXT文件，并将数据直接应用到FRED的Tabulated scatter 散射模型。 %A%^;3@  
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背景： 54v}iG  
Thorlabs和RPC Photonics联手共同推出的新型漫射体及光束整形技术，可以解决其他技术的不足，大大改善了诸如光刻系统、有效固态照明，显示，背光，显示亮度增强和投影屏等大多数应用的性能。这项我们称之为工程漫射体（Engineered DiffusersTM）的新概念，与其他技术有许多不同。与诸如磨砂玻璃、乳色玻璃和全息元件等随机漫射体截然不同，工程漫射体要求对于每个散射中心，通常为微透镜单元，都进行控制。例如全息漫射体可以视为一组随机排列的透镜，但是通过全息曝光形成的类透镜效果只能通过静态方式进行控制：而无法单独操控每个微透镜单元，这也帮助解释了全息漫射体无法控制光的分布和轮廓。另一方面，在工程漫射体中，每个微透镜单元形成漫射体，由其凹形纵断面和在阵列中的位置所确定。同时，为了确保漫射体不受输入光束变化的影响，并且不产生衍射效果，微透镜单元的分布是随机的，根据产生相应的光束形状函数所选取的概率分布函数来确定。因此，工程漫射体同时保留了随机与确定性漫射体的优点，从而实现高性能的光束整形功能。 Tw8$6KUW  
FRED是美国Photon Engineering 公司开发的光学工程仿真软件，其在杂散光分析中独特的算法、高效的准确性，使其与其它同类产品相比更具优势。本案例我们重点讲述如何由RPC Photonics的BSDF数据转为FRED可识别的散射数据。 z`XX[9$qm  
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步骤 &Yb!j  
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1、 在http://www.rpcphotonics.com/bsdf-data-optical-diffusers/下载并解压BSDF数据到某一文件夹下，选择“Raw data”文件。 |<gYzb
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2、 将     http://fred-kb.photonengr.com/wp-content/uploads/sites/2/2015/06/constructRpcScatterFile.frs脚本文件放在步骤1中的文件下。（脚本代码放在了本文的最后） _ ZMoPEW  
3、 打开FRED并运行脚本文件，会输出如下“<SAMPLE>_FRED.txt”格式，<SAMPLE>即为RPC Photonics散射片数据集 'a[|'  
例如下所示： O!#r2Y"?K1  
Sample name:  EDF-C1-56 C8ek{o)%W  
Merging data from file EDF-C1-56 0-0.txt JYc;6p$<i  
Finished merging RPC data for sample EDF-C1-56 *d b,N'rK  
FRED formatted data file:  D:\FRED\散射片数据\EDF-C1-56_FRED.txt G*^4+^Vz?  
4、 生成了FRED可识别的文件后，将散射模型导入到FRED里面 >8PGyc*9  
a. 创建一个新的散射库 V^apDV\AV  
b. 散射模型命名 DxoW,GW  
c. 改变散射模型为“Tabulated BSDF”. 54r/s#|-3  
d. 在File框出右键选择“Replace With Data From a File”, 选择步骤三生成的数据文件（如EDF-C1-56_FRED.txt ） $bOiP  
e. 切换为“Varies w/angle” 选项（假定所有的RPC Photonics datasets 数据有多个测试角度。 aYW9C<5  
f. 在底部的对话框中，选择透射散射、反射停并且你需要终止入射光线， OO#_0qK  
g. 点击OK '*lVVeSiFw  
5、 数据输入后，可点击“Plot”按钮验证BSDF模型及总的散射值 ^ZuwUuuf  
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脚本代码： a]\l:
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'#Language "WWB-COM" KDxqz$14-  
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Option Explicit n` M!K:Pq  
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Sub Main x,L<{A`z  
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    'Cleanup 17la/7l<  
    ClearOutputWindow() jzvrJ14  
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    Print "Merging RPC Photonics BSDF Data Files" Ui|z#{8&  
    SetTextColor(255,0,0) QNWGUg4*
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    Print "Note: Script should be located in the same folder as the BSDF TXT files." :
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    Print "Note: Do not run this script multiple times without deleting the output file between executions." ?`hA:X<  
    SetTextColor(0,0,0) Nux  
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    'Current directory of this script (should be the same as the text files being merged) 6pP:Q_U$  
    Dim cDir As String *{DpNV8"  
    cDir = MacroDir$ & "\" aGBUFCCa  
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    'Array which will be populated with the list of files to be merged nEHmiG  
    Dim fList() As String, curFile As String QlE]OAdB42  
    GetFileList( cDir, fList ) =aBc.PJ^  
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    Print "" 1Be/(pSc  
    Print "Files found for merging:" fb+_]{7g  
    For Each curFile In fList *(E]]8o  
        Print Chr(9) & curFile pF/s5z  
    Next iVT)V>Up  
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    'Split the first text file name found to get the sample name.  First file should be 0-0 measurement. 2Y>#FEW/  
    Dim nameArray() As String, sampName As String L;h|Sk]{  
    nameArray = Split(fList(0)," 0-0.txt") InA=ty]"_U  
    sampName  = nameArray(0) ^|%
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    Print "" *Za'^Z2  
    Print "Sample name: " & Chr(9) & sampName 7y4jk  
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    'Open an output file and write the FRED header data "O~7s}  
    Dim outFile As String nD.K*#u  
    outFile = cDir & sampName & "_FRED.txt" go9tvK  
    Open outFile For Output As #1
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    Print #1, "type bsdf_data" w"{mDL}c  
    Print #1, "format angles=deg bsdf=value scale=1" [nA1WFfM  

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    'Loop the file list, skip the two header lines and write the remaining data to file Pj8W]SA_  
    Dim lineArray() As String, curLine As Long 
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    For Each curFile In fList 1z3>nou2{  
        Print "Merging data from file " & curFile Fe1XczB  
        ReadFile( cDir & curFile, lineArray ) ZiW&*nN?M  
        For curLine = 2 To UBound(lineArray) n|fKwWB\  
            Print #1, lineArray(curLine) `ztp u ~?  
        Next `{%ImXQF  
    Next {X
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    'Close the output file 5[LDG/{Tys  
    Close #1 '>cZ7:  
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    Print "Finished merging RPC data for sample " & sampName +,]_TxL|C  
    Print "FRED formatted data file: " & Chr(9) & outFile 8.HJoos  
End Sub k%R(Qga  
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'Utility function to read the contents of a file into an array of strings. _MWW  
Function ReadFile(ByVal fileName As String, _ 3S .2  
                  ByRef lineArray() As String) As Long ''($E/  
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    ReadFile = -1 )# v}8aL  
    Dim oFSO As Object OP|X-  
    Set oFSO = CreateObject("Scripting.FileSystemObject") y[ZVi5) ,  
    Erase lineArray (ys<{Y-;  
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    Dim fid As Long JmC2buO  
    If oFSO.fileexists( fileName ) Then Rrrq>{D  
        fid = FreeFile() ;OC{B}.vH  
        Open fileName For Input As fid E~c>j<'-"<  
        lineArray = Split(Input(LOF(fid), fid), vbCrLf) [0D.+("EW  
        Close fid %?3$~d\n  
    End If Bk] `n'W  
    Set oFSO = Nothing 9*P-k.Bl  
    Return UBound( lineArray ) BCO (,k  
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End Function BoXPX2:  
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Sub GetFileList( ByVal in_dir As String, _ YZAQt*x
 
                 ByRef in_flist() As String ) ydMhb367|  
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    'Redimension the file list array &oE'|^G  
    Erase in_flist \E6 0  
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    'Tracks how many files are found *x_e] /}  
    Dim fCount As Long xt6%[)  
    fCount = 0 PZY6 I  
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    'Recurse directory and search for text files MO? }$j  
    Dim f As String e~SRGyIww  
    f = Dir$(in_dir & "*.txt") j)wrF@W  
    While f <> "" Kpkpr`:)]  
        ReDim Preserve in_flist(fCount) 3lbGG42:  
        in_flist(fCount) = f ve\@u@K^  
        fCount += 1 ^9]g5.z:  
        f = Dir$() _$/Bt?h  
    Wend N;DE,[:<  
    ReDim Preserve in_flist(fCount-1)  c& $[a%s  
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End Sub l
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