臺灣國際科展

數位攝譜儀及其數位分析方法

科展類別
臺灣國際科展
屆次
2007年
科別
物理科
學校名稱
國立大里高級中學
指導老師
黃詩翔、張啟中
作者
林育瑞、劉東霖
關鍵字
數位攝譜儀,數位分析

摘要或動機

Color is not a physical quantity, but it is a characteristic of spectra. Traditionally spectra of light sources are characterized by the wavelengths and intensities of the spectral lines. We propose an alternative way of charactering spectra using colors. Using digital cameras, convex lens, and a 600 Lines/mm grating, we design a “Digital Spectrophotometer” (Pic.1), which uses no light sensors and electrical circuits that are necessary for conventional spectrometers. To analyze a spectrum using the “Digital Spectrophotometer”, we take digital images of the diffracted light through the grating emitted by the light source and then analyze the intensity distribution of the color components of the spectral lines. The structure of the “Digital Spectrophotometer” is simple and is easy to operate. The Digital Spectrophotometer includes a computer software program we have developed called the “Digital Spectrological Method”. After enlarging the digital spectrographs to a mosaic scale and regards each mosaic as a basic color block, the Digital Spectrological Method will transform every color block into a four dimensional “color coordinates” (λ (wavelength), R(red), G(green), B(blue)), where the coordinateλ is translated from the spatial position of the spectral line and the R, G, and B coordinates specifies respectively the corresponding intensity of the red, green, and blue color components. Comparing the “color coordinates” of the unknown light sources to the known, we can easily identify the wavelengths of the lights emitted by the unknown illuminant precisely. We have accomplished the following experiments by using the “Digital Spectrophotometer”: 1. Measure the spectra of various gaseous atoms, and establish the “database of digital spectra in color coordinates” (DDSCC). 2. Compare the characters of color presentation between digital camera images and positive film of the optical camera. 3. Identify the absorption spectrum of the Solar spectrum (Fraunhofer Lines) using the DDSCC. 4. Analyze the Orion αandβ spectrum using the DDSCC. 5. Identify the 589.0 and 589.6 nm wavelength difference between the “Double Lines of sodium spectrum”. 6. Measure the range of wavelength of the colored LED and register the results into the (λ, R, G, B) coordinates. 7. Compare the range of wavelength of He-Ne Laser and commercial Laser pointer. 8. Measure the Zeeman splitting of the hydrogen atom spectrum at 0.5 Tesla.
顏色雖不是物理量,卻是光譜的特性,傳統上對光譜的分析只記錄波長及對應的強度,而非以顏色來區分。我們運用數位相機、凸透鏡及600 條/㎜光柵,設計一個以顏色成分為標準來分析各類光譜的「數位攝譜儀」(Pic.1)。這個新的設計無須使用傳統光譜儀所需之光感應器及電路設計,只需拍攝光源透過光柵的繞射影像即可分析對應之光譜。我們製作的「數位攝譜儀」包含了一個自行設計的電腦軟體程式「數位光譜分析法」;將拍攝到光譜數位影像放大成「馬賽克」,作為光譜的最小「色塊」,該程式可將每個色塊轉換為一組四維的「顏色座標」 (λ (波長),R(紅),G(綠),B(藍)),其中的λ 座標係由光譜線的位置轉換而來,而紅、綠、藍座標則記錄對應的紅、綠、藍色成分強度。與已知光源譜線的「顏色座標」比較,「數位攝譜儀」可精確測量各種未知光源放射出的光波波長且操作方便。利用「數位攝譜儀」的數位分析方法,我們完成以下實驗:1. 測量不同種類的原子光譜,建立「數位光譜資料庫」,包括氫、汞及鈉原子。2. 比較數位相機影像與光學相機正片的色彩顯影。3. 利用「數位光譜資料庫」,鑑定太陽光譜中的吸收光譜(Fraunhofer Lines)。4. 利用「數位光譜資料庫」,分析獵戶座α、β的可見光光譜。5. 鑑別波長589.0、589.6 奈米的鈉雙線。6. 用顏色座標(λ,R,G,B)測量發光二極體的波長範圍。7. 比較He-Ne 雷射與雷射光筆放光的波長範圍,發現市售雷射光筆所放之光並非單頻。
pic.01:數位攝譜儀裝置圖


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