[技术]RPC Photonics扩散片BSDF [复制链接]

摘要： MCO`\"`l  
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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。 H%G|8,4  
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背景： Xn #v!  
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。 >&D}^TMYY  
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。 (Y:?qy  
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步骤 o3,}X@p  
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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。 Cu`ty] -'  
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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） ,ocAB;K  
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 6`V~cVu  
例如下所示： 9*;OHoDh  
Sample name:  EDF-C1-56 ihBIE  
Merging data from file EDF-C1-56 0-0.txt s_4y^w]aX  
Finished merging RPC data for sample EDF-C1-56 J|.n bSE  
FRED formatted data file:  D:\FRED\散射片数据\EDF-C1-56_FRED.txt ePscSMx&  
4、 生成了FRED可识别的文件后，将散射模型导入到FRED里面 UJ7{FN=@t  
a. 创建一个新的散射库 {N'<_%cu  
b. 散射模型命名 2f0qfF  
c. 改变散射模型为“Tabulated BSDF”. r O-=):2  
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 ） [iUy_ C=qp  
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。 PS'SIX  
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， ^ RIWW0  
g. 点击OK 6S&OE k  
5、 数据输入后，可点击“Plot”按钮验证BSDF模型及总的散射值 )JXy>q#  
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脚本代码： +~\1g^h  
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'#Language "WWB-COM" <RJ+f-  
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Option Explicit M~Ph/  
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Sub Main n0%5mTUN  
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    'Cleanup Rg%Xy`gS  
    ClearOutputWindow() a,eJO??  
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    Print "Merging RPC Photonics BSDF Data Files" -fT}Nj\  
    SetTextColor(255,0,0) X3R:^ff\  
    Print "Note: Script should be located in the same folder as the BSDF TXT files." [Y-3C47  
    Print "Note: Do not run this script multiple times without deleting the output file between executions." eZMfn$McJv  
    SetTextColor(0,0,0) q$7/X;A  
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    'Current directory of this script (should be the same as the text files being merged) 9"cyZO  
    Dim cDir As String Ws;X;7tS  
    cDir = MacroDir$ & "\" }.N~jx0R  
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    'Array which will be populated with the list of files to be merged 6wH:jd9,  
    Dim fList() As String, curFile As String t`pbEjE0K  
    GetFileList( cDir, fList ) L|Bjw3K&D  
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    Print "" q
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    Print "Files found for merging:" :uB(PeAv*  
    For Each curFile In fList K96N{"{iI%  
        Print Chr(9) & curFile *QA
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    Next OPJ(ub  
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    'Split the first text file name found to get the sample name.  First file should be 0-0 measurement. 5`Y>!| Ab  
    Dim nameArray() As String, sampName As String L7n
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    nameArray = Split(fList(0)," 0-0.txt") pMV?vH  
    sampName  = nameArray(0) k|3hs('y|  
    Print "" _@! yj  
    Print "Sample name: " & Chr(9) & sampName  I|
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    'Open an output file and write the FRED header data y/;DA=  
    Dim outFile As String  V0!kvIv  
    outFile = cDir & sampName & "_FRED.txt" oQK,#>rv  
    Open outFile For Output As #1 |>Pz#DCy  
    Print #1, "type bsdf_data" TTD#ovo'  
    Print #1, "format angles=deg bsdf=value scale=1" d"OYq
 
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    'Loop the file list, skip the two header lines and write the remaining data to file *r|Zbxf(  
    Dim lineArray() As String, curLine As Long ?G 'sb}.  
    For Each curFile In fList mNKcaM?h  
        Print "Merging data from file " & curFile +zZ]Txb(  
        ReadFile( cDir & curFile, lineArray ) S~U5xM^s  
        For curLine = 2 To UBound(lineArray)
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            Print #1, lineArray(curLine) 2Ws'3Jz  
        Next rm4t  
    Next lw_@(E]E  
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    'Close the output file :eFyd`Syw  
    Close #1 %J+k.UrM  
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    Print "Finished merging RPC data for sample " & sampName \?[m%$A  
    Print "FRED formatted data file: " & Chr(9) & outFile ~(]'ah,  
End Sub 8@r>`c  

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'Utility function to read the contents of a file into an array of strings. "rHPcp"m  
Function ReadFile(ByVal fileName As String, _ c3(0BSv  
                  ByRef lineArray() As String) As Long
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    ReadFile = -1 {EJ+   
    Dim oFSO As Object lcXo
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    Set oFSO = CreateObject("Scripting.FileSystemObject") O)c3Lm-w  
    Erase lineArray p~OX1RBI  
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    Dim fid As Long (5kL6d2  
    If oFSO.fileexists( fileName ) Then F]cc?r312  
        fid = FreeFile() r{wf;5d(  
        Open fileName For Input As fid c=aVYQ"2  
        lineArray = Split(Input(LOF(fid), fid), vbCrLf) wlpcuz@  
        Close fid ik5"9b-\<  
    End If <7o@7r'0  
    Set oFSO = Nothing M$e$%kPShE  
    Return UBound( lineArray ) d?><+!a  
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End Function
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Sub GetFileList( ByVal in_dir As String, _ rE
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                 ByRef in_flist() As String ) p1s|JI  

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    'Redimension the file list array n<Ki.;-ZE  
    Erase in_flist eBqF@'DQ  
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    'Tracks how many files are found y1#QP3'Z1  
    Dim fCount As Long R)Dh;XA  
    fCount = 0 F6"QsFG  
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    'Recurse directory and search for text files zLg_0r*h1  
    Dim f As String mxICQ>s b  
    f = Dir$(in_dir & "*.txt") FYH^axpp  
    While f <> "" hA+;eXy/  
        ReDim Preserve in_flist(fCount) AjINO}b  
        in_flist(fCount) = f d.k'\1o  
        fCount += 1 aZ}z/.b]  
        f = Dir$() 1~vv<`-  
    Wend =cxG4R1x  
    ReDim Preserve in_flist(fCount-1) ;0}C2Cz'  
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End Sub Z|j\_VKhl