本發明之目的係提供一種同時能降低對環境振動影響及具有高品質重建影像之共光程數位全像系統及方法，特別是一種結合合成孔徑成像方式的共光程螺旋相位數位全系統及方法。 本發明係採用共光程干涉儀的架構，物體光波(
)經共光程架構(共光程螺旋相位光學裝置)之一透鏡（即實施方式中所稱之「第二透鏡」）作光學傅立葉轉換形成一物體空間頻譜，其外圍為高頻繞射項之一經編碼的物體頻譜(
)，及在中心為低頻直流項之一具孔徑參考光波的頻譜(
)，經該共光程螺旋相位光學裝置之另一透鏡（即實施方式中所稱之「第三透鏡」）作光學反傅立葉轉換後達成干涉作用，使用影像感測器記錄成全像影像，以提升系統的穩定性。 除此之外，本發明將使用螺旋相位板作為螺旋相位產生器以應用於數位全像系統中，透過相位移從0到2π間的數個角度中記錄下數張相位移的螺旋相位全像影像，藉由共軸架構下的時間濾波方式，不僅可有效地消除直流項與攣生像的問題，且可擷取完整的物體頻譜資訊作為重建影像，同時該重建係包含物體光波的振幅及相位的複數影像(complex image)。 為進一步提升空間解析度與相位準確度，可加入合成孔徑的成像方式以提升頻譜涵蓋範圍。藉由光束轉折器(beam steering)掃瞄以記錄不同角度之物體光波，其會在傅立葉平面的不同位置形成物體空間頻譜，藉由所得到的不同涵蓋範圍頻譜疊加，以取得更多的物體光波高頻資訊，並可同時達到空間平均地抑制雜訊之效果。 綜合以上技術，可讓系統的空間解析度與相位準確度皆有效地提升。 為達到上述目的，本發明提供一種共光程螺旋相位數位全像方法，其包括下列步驟順序： (a) 將一發射光源入射至一待測物體(50)以形成一物體光波(
)； (b) 該物體光波(
)經一共光程螺旋相位光學裝置(20)之一透鏡作光學傅立葉轉換後，在該共光程螺旋相位光學裝置(20)之一螺旋相位產生器(210)上產生一物體空間頻譜，並透過螺旋相位產生器(210)之濾波功能將該物體空間頻譜的同心圓外圍（高頻繞射項）形成一經編碼的物體頻譜(
)及在同心圓中心形成頻譜為低頻直流項之一具孔徑參考光波的頻譜(
)，接著該經編碼的物體頻譜與該具孔徑參考光波的頻譜，再經另一透鏡作光學反傅立葉轉換後達成干涉作用，形成第一螺旋相位全像影像； (c) 重複步驟(b)，將該經編碼的物體頻譜(
)由該螺旋相位產生器(210)進行螺旋相位移演算法作複數次相位移後，形成複數個相位移的螺旋相位全像影像； (d) 將該第一螺旋相位全像影像及該複數個相位移的螺旋相位全像影像藉由一影像裝置(30)作影像重建演算法，在與該影像裝置(30)相距影像重建距離(
z)處，形成具有振幅及相位之一第一重建物體影像(
)；及 (e) 藉由旋轉該合成孔徑光學裝置(10)之一光束轉折器(120)，使另一角度之該發射光源入射至該待測物體(50)形成另一角度的物體光波(
)，重複上述步驟(b)、(c)及(d)，形成另一角度的重建物體影像(
)，該第一重建物體影像與該另一角度的重建物體影像經該影像裝置(30)運算後，形成一合成孔徑的重建物體影像(
)。 本發明另提供一種共光程螺旋相位數位全像系統，其包括： 一光源產生器(40)，其用以產生一發射光源，其可為一同調光、低同調光以及非同調光；一合成孔徑光學裝置(10)，其將該發射光源入射至一待測物體(50)以形成一物體光波(
)； 一共光程螺旋相位光學裝置(20)，其包括一螺旋相位產生器(210)，及用以使該物體光波(
)經光學傅立葉轉換後形成一物體空間頻譜的透鏡，以便能在該螺旋相位產生器(210)上產生螺旋相位濾波效果；所形成之該物體空間頻譜的同心圓外圍調制形成一經編碼的物體頻譜(
)，在同心圓中心則形成一低頻直流項之一具孔徑參考光波的頻譜(
)；該共光程螺旋相位光學裝置(20)尚包括用以使該經編碼的物體頻譜(
)與該具孔徑參考光波的頻譜(
)經光學反傅立葉轉換之另一透鏡，該編碼的物體頻譜(
)與具孔徑參考光波的頻譜(
)二者經光學反傅立葉轉換後達成干涉作用，形成一第一螺旋相位全像影像， 重複藉由該螺旋相位產生器(210)將該物體空間頻譜以螺旋相位移演算法進行複數次相位移，再經光學反傅立葉轉換後，形成複數個相位移的螺旋相位全像影像， 其中該第一螺旋相位全像影像及該複數個相位移的螺旋相位全像影像經一影像裝置(30)擷取，並作影像重建演算法後，在與該影像裝置(30)相距影像重建距離(
z)處，形成具有振幅及相位之一第一重建物體影像， 其中藉由旋轉該合成孔徑光學裝置(10)之一光束轉折器(120)，使一不同角度之該發射光源入射至該待測物體(50)，進而在該螺旋相位產生器(210)之不同位置形成另一角度的物體空間頻譜，進而形成另一角度的第一螺旋相位全像影像，再經該螺旋相位產生器(210)以螺旋相位移演算法進行複數次相位移，進而形成另一角度的複數個相位移的螺旋相位全像影像，該另一角度的第一螺旋相位全像影像及該另一角度的複數個相位移的螺旋相位全像影像再經該影像裝置(30)擷取並作影像重建演算法後，進而形成另一角度的重建物體影像，將該第一重建物體影像與該另一角度的重建物體影像經該影像裝置(30)運算後形成一合成孔徑的重建物體影像(
)。 本發明所述之共光程螺旋相位數位全像系統及方法，採用共光程的架構，利用一個透鏡將物體光波進行光學傅立葉轉換形成物體空間頻譜，並於傅立葉平面中利用螺旋相位產生器產生螺旋相位濾波，使物體空間頻譜的同心圓外圍形成一經編碼的物體頻譜，及在同心圓中心位置形成一具孔徑參考光波的頻譜，再經另一個透鏡作光學反傅立葉轉換後達成干涉作用，形成共光程的螺旋相位全像影像，藉由此共光程架構可降低環境振動的影響，進而大幅增加裝置的穩定性。 又，本案發明將螺旋相位產生器置於傅立葉平面，透過螺旋相位產生器將經編碼的物體頻譜作複數次相位移後，取得複數個相位移的螺旋相位全像影像，接著使用時間濾波方式以有效消除直流項與孿生像的問題，以利於獲得高品質的重建物體影像。 再者，本案發明採用合成孔徑的成像方式，利用光束轉折器將不同角度之發射光源入射至物體，形成不同角度的物體光波，其會在傅立葉平面的不同位置形成物體空間頻譜，進而提升頻譜涵蓋範圍，藉由將所得到的不同涵蓋範圍頻譜疊加，可提升空間解析度及相位準確度。
The object of the present invention is to provide a common optical path digital holographic system and method capable of reducing environmental vibration and high quality reconstructed images, in particular, a common optical path spiral phase digital whole system and method combining synthetic aperture imaging . The invention adopts the architecture of a common optical path interferometer, object light wave ( a lens of a common optical path architecture (a total optical path spiral phase optical device) (referred to as a "second lens" in the embodiment) for optical Fourier transform to form an object spatial spectrum, the periphery of which is a high frequency diffraction term One of the encoded object spectra ( ), and the spectrum of the aperture reference light wave in the center of the low frequency DC term ( The other lens (that is, the "third lens" referred to in the embodiment) of the common optical path spiral phase optical device is subjected to optical inverse Fourier transform to achieve interference, and is recorded as a holographic image by using an image sensor. Improve the stability of the system. In addition, the present invention will use a spiral phase plate as a spiral phase generator for use in a digital holographic system to record a number of phase shifted helical phase holograms through phase shifts from a number of angles between 0 and 2π. The image, by the time filtering method under the coaxial architecture, can not only effectively eliminate the DC and twin images, but also capture the complete object spectrum information as the reconstructed image, and the reconstruction includes the amplitude of the object light wave and The complex image of the phase. To further improve spatial resolution and phase accuracy, synthetic aperture imaging methods can be added to increase spectral coverage. Scanning by beam steering to record light waves of objects at different angles, which will form the spatial spectrum of the object at different positions of the Fourier plane, and obtain more object light waves by superimposing the spectral coverage of different coverage areas. High-frequency information, and at the same time achieve the effect of spatially suppressing noise. By combining the above technologies, the spatial resolution and phase accuracy of the system can be effectively improved. To achieve the above object, the present invention provides a common optical path spiral phase digital holography method comprising the following sequence of steps: (a) incident a light source onto an object to be measured (50) to form an object light wave ( (b) the object light wave ( An optical spatial Fourier transform is performed on a lens of a common optical path spiral phase optical device (20), and an object spatial spectrum is generated on a spiral phase generator (210) of the common optical path spiral phase optical device (20), and The concentric circle periphery (high-frequency diffraction term) of the spatial spectrum of the object is formed into a coded object spectrum by the filtering function of the spiral phase generator (210) ( And a spectrum of aperture-referenced light waves with a spectrum of low-frequency DC terms at the center of the concentric circle ( And then the spectrum of the encoded object and the spectrum of the reference optical wave having the aperture are subjected to optical inverse Fourier transform by another lens to achieve interference to form a first spiral phase holographic image; (c) repeating step (b) , the encoded object spectrum ( a spiral phase shift algorithm is performed by the spiral phase generator (210) for a plurality of phase shifts to form a plurality of phase-shifted spiral phase hologram images; (d) the first spiral phase hologram image and the complex number The phase-shifted spiral phase hologram image is reconstructed by an image device (30), and a first reconstruction having amplitude and phase is formed at an image reconstruction distance ( z ) from the image device (30). Object image And (e) rotating the incident light source at another angle to the object to be tested (50) to form another angle of the object light wave by rotating the beam deflector (120) of the synthetic aperture optical device (10) ( ), repeat steps (b), (c) and (d) above to form an image of the reconstructed object at another angle ( And the reconstructed object image of the first reconstructed object and the reconstructed object image of the other angle are processed by the image device (30) to form a reconstructed object image of the synthetic aperture ( ). The present invention further provides a common optical path spiral phase digital holography system, comprising: a light source generator (40) for generating a light source, which can be a dimming, a low dimming, and a non-coinciding light; a synthetic aperture optical device (10) that injects the emission source into an object to be measured (50) to form an object light wave ( a total optical path spiral phase optical device (20) comprising a spiral phase generator (210) and for illuminating the object ( a lens that forms a spatial spectrum of the object after optical Fourier transform, so that a spiral phase filtering effect can be generated on the spiral phase generator (210); a concentric peripheral modulation of the spatial spectrum of the object formed forms a coded object spectrum ( ), at the center of the concentric circle, a spectrum of a low-frequency DC term with an aperture reference light wave is formed ( The common optical path spiral phase optical device (20) further includes a spectrum for the encoded object ( ) and the spectrum of the aperture reference light wave ( Another lens that is optically inverse Fourier transformed, the encoded object spectrum ( ) and the spectrum with aperture reference light waves ( The two sides undergo an optical inverse Fourier transform to achieve interference, forming a first spiral phase holographic image, and repeating the phase phase shift of the object spatial spectrum by the spiral phase generator (210) by a plurality of phase shifts by the spiral phase generator (210) After the optical inverse Fourier transform, a plurality of phase-shifted spiral phase hologram images are formed, wherein the first spiral phase hologram image and the plurality of phase-shifted spiral phase hologram images are transmitted through an image device (30). After taking an image reconstruction algorithm, a first reconstructed object image having amplitude and phase is formed at an image reconstruction distance ( z ) from the image device (30), wherein the synthetic aperture optical device is rotated by 10) a beam deflector (120) that causes a different angle of the emission source to be incident on the object to be tested (50), thereby forming a spatial spectrum of the object at another angle at different positions of the spiral phase generator (210) And forming a first spiral phase hologram image of another angle, and then performing a plurality of phase shifts by the spiral phase shift algorithm by the spiral phase generator (210), thereby forming another angle a plurality of phase-shifted spiral phase hologram images, the first spiral phase hologram image of the other angle and the plurality of phase-shifted spiral phase hologram images of the other angle are captured by the image device (30) After the image reconstruction algorithm is performed, a reconstructed object image is formed at another angle, and the first reconstructed object image and the reconstructed object image of the other angle are processed by the image device (30) to form a reconstructed object image of the synthetic aperture. ( ). The common optical path spiral phase digital holographic system and method of the present invention adopts a common optical path architecture, uses a lens to optically Fourier transform an object light wave into an object spatial spectrum, and generates a spiral phase generator in a Fourier plane. The spiral phase filtering forms a spectrum of the encoded object around the concentric circle of the spatial spectrum of the object, and forms a spectrum of the aperture reference light wave at the center of the concentric circle, and then performs an optical inverse Fourier transform through another lens to achieve interference. The spiral phase holographic image of the common optical path can reduce the influence of environmental vibration by the common optical path architecture, thereby greatly increasing the stability of the device. Moreover, in the invention, the spiral phase generator is placed in the Fourier plane, and the encoded object spectrum is phase-shifted by the spiral phase generator to obtain a plurality of phase-shifted spiral phase hologram images, and then time filtering is used. Effectively eliminate the problems of DC and twin images to facilitate the acquisition of high quality images of reconstructed objects. Furthermore, the invention adopts a synthetic aperture imaging method, and uses a beam deflector to inject light sources of different angles into an object to form object light waves of different angles, which form an object spatial spectrum at different positions of the Fourier plane, thereby enhancing spectrum coverage. The range, by superimposing the different coverage spectrums obtained, can improve spatial resolution and phase accuracy.
下文將參照圖式詳細描述本發明之實施態樣。 圖1例示本案發明之共光程螺旋相位數位全像系統，其包括：合成孔徑光學裝置(10)、共光程螺旋相位光學裝置(20)、影像裝置(30)、光源產生器(40)。圖1中的50代表待測物體。 合成孔徑光學裝置(10)包括：光擴束組(110)，其包括光擴束器(111)、第四透鏡(112)及第五透鏡(113)；一可旋轉之光束轉折器(120)，其至少包括一掃瞄鏡，並可進一步包括一光柵、一空間光調制器、一稜鏡及一數位微鏡裝置，以用於轉折光束；分光鏡(130)；第一物鏡組(140)，其包括：第一透鏡(141)及物鏡(142)，其中物鏡可為顯微鏡、望遠鏡、廣角鏡或變焦鏡等光學鏡頭，較佳地，第一物鏡組(140)具有焦距為150mm之第一透鏡(141)及數值孔徑(Numerical Aperture, NA)為0.90之物鏡(142)，其中第一透鏡(141)之前後焦距可以相等，也可以在不影響成像品質的條件下略有些微差異，物鏡(142)之前後焦距可以相等，也可以在不影響成像品質的條件下略有些微差異。光擴束器(111)、第四透鏡(112)、第五透鏡(113)之參數設定、功能與效果係根據去除發射光源因光學元件之平整度與瑕疵等造成之空間雜訊與光學像差之需要；第一透鏡(141)、物鏡(142)之參數設定、功能與效果則係根據習知自物體光波取得高空間解析度與消除光學像差技術可得知。 共光程螺旋相位光學裝置(20)包括螺旋相位產生器(210)（spiral phase generator）、第二透鏡(220)、第三透鏡(221)、第一偏振片(230)及第二偏振片(231)。第二透鏡(220)及第三透鏡(221)亦可稱為第二物鏡組，其中物鏡可為顯微鏡、望遠鏡、廣角鏡或變焦鏡等光學鏡頭，較佳地，第二物鏡組具有焦距為250mm之第二透鏡(220)及焦距為250mm之第三透鏡(221)，其中第二透鏡(220)之前後焦距可以相等，也可以在不影響成像品質的條件下有些微差異，第三透鏡(221)之前後焦距可以相等，也可以在不影響成像品質的條件下有些微差異。第一偏振片(230)係為線性偏振片，亦為起偏板。第二偏振片(231)係為線性偏振片，亦為檢偏板。螺旋相位產生器(210)係採用矽基液晶空間光調制器(Liquid Crystal On Silicon, 簡稱LCoS)，包括：螺旋相位板(spiral phase plate)、空間光調制器（spatial light modulator, 簡稱SLM）等螺旋相位元件，其具有螺旋相位板之功能，以實現螺旋相位濾波以及相位移，同時，根據該閃耀光柵所使用的空間頻率，可將經編碼的物體頻譜與具孔徑參考光波的頻譜轉折一微小角度(θ
d)，以避免來自矽基液晶空間光調制器的高頻雜訊與直流項影響所記錄的螺旋相位全像影像；例示之螺旋相位產生器為矽基液晶空間光調制器之像素數目為1,920´1,080 pixels，像素大小為6.4 μm ´6.4 μm。 影像裝置(30)包括影像記錄器(310)及影像處理器(320)，影像記錄器(310)可為互補式金屬氧化物半導體(Complementary Metal-Oxide-Semiconductor, CMOS) 感光耦合元件(Charge-coupled Device; CCD)、光感測器(Photodetector)等光偵測器，較佳地，其像素數目為1,280´1,024 pixels與像素大小為5.2 μm ´5.2 μm。影像記錄器(310)亦可為光偵測器陣列(detection array)，其它具有記錄影像功能之裝置亦不在此限。影像處理器(320)，其連接影像記錄器(310)，將影像處理器(320)所記錄之影像加以運算。 光源產生器(40)，其用以產生發射光源，該發射光源可產生同調光、低同調光或非同調光，例如：產生垂直共振腔面射型雷射(Vertical-Cavity Surface-Emitting Laser；VCSEL)、半導體雷射(Semiconductor laser)、固態雷射(Solid-state laser)、氣態雷射(Gas laser)、液體雷射(Dye laser)、光纖雷射(Fiber laser)，較佳地，為可見光的波長650nm之半導體雷射，或者其為發光二極體(LED)。 參照圖1，本發明之步驟(a)，由光源產生器(40)產生之發射光源，如雷射光，經空間濾波組(110)以產生擴束及準直之平面光束，再入射至光束轉折器(120)後入射至分光鏡(130)，產生兩道光束，其一為穿透光束，另一為第一反射光束(r)，將該第一反射光束(r)利用光學遮攔方式濾除，以避免其影響影像品質，該穿透光束通過第一物鏡組(140)以將光束轉折器所旋轉至第一物鏡組的入射角度，依據第一物鏡組(140)的放大或縮小倍率來進行入射角度的放大或縮小，再入射至待測物體(50)。若待測物體(50)為不透明，則穿透光束入射至待測物體(50)後會反射，並再經第一物鏡組(140)後入射至分光鏡(130)，其為具有物體的振幅與相位影像資訊之物體光波(
)；若待測物體(50)為半透明或全透明，則會配置兩組第一物鏡組(140, 140')且原則上可不配置分光鏡(130)，平面光束入射至光束轉折器(120)後即通過第一物鏡組(140)，入射至待測物體(50)後會穿透待測物體(50)，並經過另一第一物鏡組(140')，其中另一第一物鏡組(140')包含另一第一透鏡(141')及另一物鏡(142')，此外，兩組第一物鏡組(140, 140')的放大或縮小倍率可不相同（如圖8所示）。本發明可採用穿透或反射所得到之物體光波(
)而分別採用如圖8與圖1所示之系統。其中該物體光波(
)可為成像或非成像的繞射光波。 本發明例示於圖1之步驟(b)，係採用由該待測物體(50)所反射之物體光波(
)，該物體光波(
)在分光鏡(130)處反射（或者，如前述，亦可採用穿透透明或半透明物體之物體光波），首先透過第一偏振片(230)調制物體光波(
)入射至螺旋相位產生器(210)的偏振特性，再經第二透鏡(220)作光學傅立葉轉換後，使該物體光波(
)於螺旋相位產生器(210)形成一物體光波的傅立葉頻譜(即：物體光波(
)所形成之空間頻譜)，此空間頻譜的同心圓外圍為物體光波的高頻繞射項(即：物體光波(
)所形成之空間頻譜的高頻繞射項(
))，而在同心圓中心處為物體光波的低頻直流項，螺旋相位產生器(210)會對外圍高頻繞射項之物體空間頻譜進行調制以形成經編碼的物體頻譜(
)，對中心低頻直流項之物體空間頻譜進行濾波作用以產生一具孔徑參考光波的頻譜(
)，該經編碼的物體頻譜(
)及該具孔徑參考光波的頻譜(
)經第三透鏡(221)作光學反傅立葉轉換，二者達成干涉作用後，經第二偏振片(231)調制其偏振特性，使其具有適當的振幅與相位特性，於影像記錄器(310)記錄為第一螺旋相位全像影像(相位移角度為α=0)，如圖4A右下所示。其中影像記錄器(310)可置於成像平面，亦可置於非成像平面，而非成像平面與成像平面相距一定距離，稱為影像重建距離(z)。 本發明之步驟(c)，螺旋相位產生器(210)具有螺旋相位板功能，可藉由螺旋相位移演算法，將上述同一個物體光波(
)在螺旋相位產生器(210)上所形成同一個物體空間頻譜之外圍高頻繞射項之經編碼的物體頻譜(
)作複數次的相位移。較佳地，可為二次、三次、四次或五次以上相位移。每經由一次相位移後，即產生另一相位移的經編碼的物體頻譜(
)，其與具孔徑參考光波的頻譜(
)經第三透鏡(221)作光學反傅立葉轉後換達成干涉作用，於影像記錄器(310)形成另一相位移的螺旋相位全像影像。亦即，若經由三次相位移(相位移角度為α=π/2, π, 3π/2)後，則會另產生經過三次相位移的的螺旋相位全像影像(不包括第一螺旋相位全像影像)，如圖4B、圖4C及圖4D各圖右下所示。同理可知，經複數次相位移後，會產生複數個相位移的螺旋相位全像影像。 本發明之步驟(d)，將第一螺旋相位全像影像及經複數次相位移後所產生的複數個相位移的螺旋相位全像影像，藉由影像處理器(320)以影像重建演算法運算後完成影像重建，可設定在距離影像記錄器(310)一影像重建距離(z)處，形成具有相位影像及振幅影像之第一重建物體影像。藉由此影像重建方式，可取得待測物體(50)的成像及非成像的重建物體影像(含振幅與相位影像)。影像記錄器(310)的位置可置於成像平面(z=0)或非成像平面(z≠0)。 本發明之步驟(e)，利用合成孔徑的方式，藉由旋轉光束轉折器(120)，使光源產生器(40)所產生之發射光源，以另一角度入射至待測物體(50)，形成另一角度的物體光波(
)。亦即，將光束轉折器(120)旋轉至另一不同的角度，即會產生另一不同角度的物體光波(
)。將該另一角度的物體光波(
)，再次經由上述步驟(b)、(c)及(d)後，形成另一角度的重建物體影像(
)。也就是說，將光束轉折器(120)沿著一軸(
x軸或
y軸)進行一系列不同角度的旋轉後，使發射光源以一系列不同角度入射至待測物體(50)，形成一系列不同角度的物體光波(
)，進而產生複數個不同角度的重建物體影像，將該第一重建物體影像(
)及該複數個不同角度的重建物體影像(
)藉由影像處理器(320)作數值傅立葉轉換後將其頻譜疊加，再經數值反傅立葉轉換後，形成一合成孔徑的重建物體影像(
)。 為進一步了解本發明的運算過程，於下文中提供運算符號及運算式。 如上所述本發明之步驟(a)，藉由一光束轉折器(120)將一發射光源入射至一待測物體(50)形成一物體光波(
)。再如本發明之步驟(b)，藉由第二透鏡(220)作光學傅立葉轉換形成該物體光波的空間頻譜，該空間頻譜的同心圓外圍為物體光波所形成之空間頻譜的高頻繞射項(
)，而在同心圓中心處為物體光波的低頻直流項之具孔徑參考光波的頻譜(
)，接著透過該螺旋相位產生器(210)之螺旋相位濾波功能對外圍高頻繞射項之物體空間頻譜進行調制以形成編碼的物體頻譜(
)，對中心低頻直流項之物體空間頻譜進行濾波作用以產生一具孔徑參考光波的頻譜(
)。在下列的表示式中，在空間平面的表示符號不加註上標，例如：
,
,
，而在頻譜平面的表示符號則加註上標，例如：
,
,
，以茲區別。該螺旋相位產生器(210)係使用矽基液晶空間光調制器所產生，其表示式為
s(
r,
ϕ)=
rexp(
iϕ)，其中，徑向極座標(radial polar coordinate)是
r，
ϕ則表示從0~2π的相位變化值。該經編碼的物體頻譜(
)及該具孔徑參考光波的頻譜(
)經第三透鏡(221)作光學反傅立葉轉換，二者達成干涉作用在空間平面可表示為
，形成第一螺旋相位全像影像。 本發明之步驟(c)，將該物體光波(
)重複步驟(b)，並對該經編碼的物體頻譜(
)及具孔徑參考光波的頻譜(
)作複數次相位移後，形成複數個相位移的螺旋相位全像影像，其中該經編碼的物體光波在空間平面可表示為
，捲積運算為符號U，螺旋相位濾波器經過反傅立葉轉換(
)所得到的結果為
S，即
，螺旋相位濾波的相位移角度為
，其中
q是相位移的總次數，和
p是介於0到
q-1之間的整數。 本發明之步驟(d)，將第一螺旋相位全像影像及經複數次相位移後所產生的複數個相位移的螺旋相位全像影像，藉由影像處理器(320)以影像重建演算法運算後完成影像重建，並可取得待測物體(50)的成像及非成像的重建物體影像(含振幅與相位影像)。 本發明之步驟(e)，將運用一合成孔徑裝置的一光束轉折器(120)對該待測物體(50)進行一系列的不同角度入射，考慮發射光源的平面波將沿著
x-y軸對樣本進行掃瞄，該物體光波將與螺旋相位濾波器作用且表示如下：
, (1) 物體光波在傅立葉平面上所形成之空間頻譜的高頻繞射項為(
)，而總掃瞄角度階數為
M和
N，該階數
m和
n表示1到
M和
N之間的整數、螺旋相位濾波器為
s、平面波與傳播方向之間的角度可由方向餘弦表示為
與
，光學系統的傳遞函數則係由一圓形孔徑
所表示，其中的截止頻率為
。 接著，該物體光波所形成之空間頻譜的高頻繞射項(
)經由第三透鏡(221)作光學反傅立葉轉換所形成經編碼的物體頻譜(
)可以表示為：
(2) 考慮當該物體光波繞射一段距離z至成像或非成像平面時，可根據菲涅耳-克希荷夫繞射公式(Fresnel-Kirchhoff diffraction formula)表示為：
, (3) 其中，螺旋相位產生器(210)的相位移所作用後的螺旋相位數位全像影像為
，接著使用影像裝置記錄該全像影像的表示為：
, (4) 並採用複數平均(complex average)的方法來獲得物體光波的資訊如下：
, (5) 參考光的共軛複數(complex conjugate)為
與相位移方向相反的螺旋相位函數為
，將用於重建繞射的物體影像。並運用捲積運算法來對該繞射的物體影像進行數值對焦如下：
, (6) 最後，沿著
x-y軸掃瞄的複數個傾斜角度的重建物體影像分別作數值傅立葉轉換，並進行頻譜的疊加，如下：
. (7) 經由上述影像處理器所運算後將可獲得具有高空間解析度與相位準確度的合成孔徑的重建物體影像。 在實施例中，當光束轉折器(120)旋轉一角度時，經過第一物鏡組(140)後該旋轉角度，將依據第一物鏡組的放大倍率(=83倍)使得入射至待測物體(50)的角度放大為光束轉折器(120)所旋轉角度的83倍。 參照圖2，其示意說明不同角度的物體光波(
)經第二透鏡(220)作光學傅立葉轉換後，其物體的空間頻譜會在螺旋相位產生器(210)上形成不同的頻譜範圍。外圍高頻繞射項為經編碼的物體頻譜(
)，帶有物體影像的高頻資訊並經過螺旋相位調制，中心低頻直流項為具孔徑參考光波的頻譜(
)，理想上僅包含物體的低頻直流資訊。經編碼的物體頻譜光波(
)及具孔徑參考光波的頻譜(
)再經由第三透鏡(221)作光學反傅立葉轉換後，二者達成干涉作用。 此外，進一步解釋本發明所運用之螺旋相位產生器(210)，其螺旋相位移演算法之運作係利用螺旋相位板(如圖3A所示)及閃耀光柵(如圖3B所示)之疊加，圖3C為螺旋相位板與閃耀光柵疊加效果之示意。圖4A、圖4B、圖4C及圖4D之各圖左上示意分別利用螺旋相位產生器(210)使螺旋相位板之相位移角度為α=0, π/2, π, 3π/2，並與閃耀光柵疊加，圖4A、圖4B、圖4C及圖4D之各圖右下則為依前述方式進行螺旋相位移演算法後獲得的影像。 圖5A-5F顯示本發明在步驟(d)影像重建部分之效果。圖5A及5D分別為影像重建距離(z)為2.3cm之振幅影像及相位影像。圖5B及5E分別為影像重建距離(z)為4.7cm之振幅影像及相位影像。圖5C及5F分別為影像重建距離(z)為7.1cm之振幅影像及相位影像。由於步驟(c)中之重建物體影像為具有振幅(amplitude)及相位(phase)訊息的複數影像(complex image)，故可根據此二者達成在不同影像重建距離(z)處的影像重建，完成數位全像。 圖6A為經過螺旋相位移演算法作相位移但未經過合成孔徑方式所獲得之振幅影像；圖6B為經過螺旋相位移演算法作相位移但未經過合成孔徑方式所獲得之三維輪廓影像；圖6C為根據圖6A、6B之影像，將欲量測區域之三維輪廓影像橫截面量化之量測結果圖，其顯示量得之孔的深度(即段差，或稱step height)約181 nm。 圖6D為經過螺旋相位移演算法作相位移且亦經過合成孔徑方式所獲得之振幅影像；圖6E為經過螺旋相位移演算法作相位移且亦經過合成孔徑方式所獲得之三維輪廓影像；圖6F為根據圖6D及6E之影像，將欲量測區域之三維輪廓影像橫截面量化之量測結果圖，其顯示量得之孔的深度(即段差，或稱step height)約180 nm。比較圖6C及圖6F可知，相位量測標準差由約σ≈±8.8 nm降低至約σ≈±4.0 nm，顯示同時採用螺旋相位移方式與合成孔徑方式所取得之數位全像的相位準確度提高約2倍。 圖7A-7F為針對圖7G之試片其上之刻線與刻線之間的距離（線寬）進行量測。圖7G右上與右下之刻線之各自間隔（線寬）分別為320 nm及282 nm。圖7A及圖7B分別為採用螺旋相位移所取得圖7G之試片之數位全像振幅影像、同時採用合成孔徑方法及螺旋相位移之圖7G之試片之數位全像之振幅影像；比較圖7A及圖7B可知，後者取得之數位全像的空間解析度較高，較能清楚呈現原圖形。圖7C為將圖7A及圖7B之振幅影像中之線寬作量化分析的結果，該紅色虛線部分為合成孔徑與螺旋相位移共用時取得之量測結果，其較能將圖7G之試片上之刻線之位置正確反映，亦即驗證了同時採用合成孔徑方法及螺旋相位移之數位全像之空間解析度較佳。類似地，圖7D及圖7E分別為僅使用螺旋相位移法取得圖7G之試片之數位全像之相位影像、共同使用合成孔徑方式與螺旋相位移法取得圖7G之試片之數位全像之相位影像。圖7F為圖7D及圖7E之相位影像量化分析的結果，該紅色虛線部分為合成孔徑與螺旋相位移共用時（即圖7E）取得之量測結果，其較能將圖7G之試片上之刻線之位置正確反映，顯示合成孔徑與螺旋相位移共用所獲致之數位全像具有較佳的空間解析度。 本發明之實施方式與效果已經由上述具體實施例說明。上述實施例僅作為例示用，任何所屬技術領域中具有通常知識者應可基於上述揭示或教示，而對本發明進行任何置換、修飾或變化。這些改變均應涵蓋在本發明之範疇內。
Embodiments of the present invention will be described in detail below with reference to the drawings. 1 illustrates a common optical path spiral phase digital holography system of the present invention, comprising: a synthetic aperture optical device (10), a common optical path spiral phase optical device (20), an imaging device (30), and a light source generator (40). . 50 in Fig. 1 represents an object to be tested. The synthetic aperture optical device (10) comprises: a light beam expanding group (110) comprising a light beam expander (111), a fourth lens (112) and a fifth lens (113); and a rotatable beam turner (120) And comprising at least one scanning mirror, and further comprising a grating, a spatial light modulator, a chirp and a digital micromirror device for turning the beam; a beam splitter (130); the first objective lens group (140) The first lens (141) and the objective lens (142), wherein the objective lens can be an optical lens such as a microscope, a telescope, a wide-angle lens or a zoom lens. Preferably, the first objective lens group (140) has a focal length of 150 mm. A lens (141) and a numerical aperture (NA) are an objective lens (142) of 0.90, wherein the front lens may have equal front and back focal lengths, or may be slightly different under conditions that do not affect imaging quality. The focal length of the objective lens (142) can be equal before and after, and it can be slightly different under the condition that the imaging quality is not affected. The parameter setting, function and effect of the optical beam expander (111), the fourth lens (112), and the fifth lens (113) are based on removing spatial noise and optical images caused by the flatness and flaw of the optical element. The need for difference; the parameter setting, function and effect of the first lens (141) and the objective lens (142) are known from the conventional techniques for obtaining high spatial resolution and eliminating optical aberrations from object light waves. The common optical path spiral phase optical device (20) includes a spiral phase generator (210), a second lens (220), a third lens (221), a first polarizer (230), and a second polarizer. (231). The second lens (220) and the third lens (221) may also be referred to as a second objective lens group, wherein the objective lens may be an optical lens such as a microscope, a telescope, a wide-angle lens or a zoom lens. Preferably, the second objective lens group has a focal length of 250 mm. The second lens (220) and the third lens (221) having a focal length of 250 mm, wherein the second lens (220) can be equal in front and back focal length, or can be slightly different under the condition that does not affect the image quality, the third lens ( 221) Before and after the focal length can be equal, there can be some slight differences without affecting the imaging quality. The first polarizing plate (230) is a linear polarizing plate and is also a polarizing plate. The second polarizing plate (231) is a linear polarizing plate and is also an analyzer. The spiral phase generator (210) adopts a Liquid Crystal On Silicon (LCoS), and includes: a spiral phase plate, a spatial light modulator (SLM), and the like. a spiral phase element having the function of a spiral phase plate to achieve spiral phase filtering and phase shift, and at the same time, according to the spatial frequency used by the blazed grating, the spectrum of the encoded object and the spectrum of the aperture reference wave can be turned into a small Angle (θ d ) to avoid the spiral phase hologram image recorded by the high frequency noise and DC term from the 矽-based liquid crystal spatial light modulator; the illustrated spiral phase generator is the pixel of the 矽-based liquid crystal spatial light modulator The number is 1,920 ́1,080 pixels and the pixel size is 6.4 μm ́6.4 μm. The image device (30) includes an image recorder (310) and an image processor (320), and the image recorder (310) can be a complementary metal-oxide-semiconductor (CMOS) photosensitive coupling element (Charge- A photodetector such as a CCD, a photodetector, or the like, preferably has a pixel number of 1,280 ́1,024 pixels and a pixel size of 5.2 μm ́5.2 μm. The image recorder (310) can also be a detector array, and other devices having the function of recording images are not limited thereto. The image processor (320) is coupled to the image recorder (310) and operates on the image recorded by the image processor (320). a light source generator (40) for generating an emission light source, which can generate the same dimming, low dimming or non-coinciding light, for example, generating a vertical-cavity surface-emission laser (Vertical-Cavity Surface-Emitting Laser; VCSEL), semiconductor laser, solid-state laser, gas laser, Dye laser, fiber laser, preferably, A semiconductor laser having a visible light wavelength of 650 nm, or a light emitting diode (LED). Referring to Fig. 1, in step (a) of the present invention, an emission source generated by a light source generator (40), such as laser light, is spatially filtered (110) to produce a beam beam that is expanded and collimated, and then incident on the beam transition. The device (120) is then incident on the beam splitter (130) to generate two beams, one of which is a penetrating beam, and the other is a first reflected beam (r), which is filtered by an optical obstruction method. In addition, to avoid affecting the image quality, the penetrating beam passes through the first objective lens group (140) to rotate the beam deflector to the incident angle of the first objective lens group, according to the magnification or reduction ratio of the first objective lens group (140). To enlarge or reduce the incident angle, and then incident on the object to be tested (50). If the object to be tested (50) is opaque, the penetrating beam will be reflected after being incident on the object to be tested (50), and then passed through the first objective lens group (140) and then incident on the beam splitter (130), which has an object. Amplitude and phase image information of object light waves ( If the object to be tested (50) is translucent or fully transparent, two sets of first objective lens sets (140, 140') are arranged and in principle no spectroscope (130) may be arranged, and the planar light beam is incident on the beam deflector ( 120) after passing through the first objective lens group (140), after entering the object to be tested (50), it will penetrate the object to be tested (50) and pass through another first objective lens group (140'), and the other first The objective lens group (140') includes another first lens (141') and another objective lens (142'). In addition, the magnification or reduction ratio of the two sets of first objective lens groups (140, 140') may be different (Fig. 8) Shown). The invention can adopt the light wave of the object obtained by penetrating or reflecting ( ) The systems shown in Figures 8 and 1 are used respectively. Where the object light wave ( ) can be diffracted light waves for imaging or non-imaging. The present invention is exemplified in the step (b) of FIG. 1 , which uses the object light wave reflected by the object to be tested ( 50 ) ( ), the object light wave ( Reflecting at the beam splitter (130) (or, as mentioned above, also using object light waves that penetrate transparent or translucent objects), first modulating the object light waves through the first polarizer (230) ( a polarization characteristic incident on the spiral phase generator (210), and then optically Fourier-converted by the second lens (220) to cause the object light wave ( a Fourier spectrum of an object light wave formed by the spiral phase generator (210) (ie: object light wave ( The spatial spectrum formed by the space, the periphery of the concentric circle of the spatial spectrum is the high-frequency diffraction term of the object light wave (ie: the object light wave ( High frequency diffraction term of the spatial spectrum formed ( )), and at the center of the concentric circle is the low-frequency DC term of the object light wave, the spiral phase generator (210) modulates the spatial spectrum of the object of the peripheral high-frequency diffraction term to form the encoded object spectrum ( Filtering the spatial spectrum of the object of the central low-frequency DC term to produce a spectrum of aperture-referenced light waves ( ), the encoded object spectrum ( And the spectrum of the aperture reference light wave ( After the third lens (221) is used for optical inverse Fourier transform, after the two sides achieve interference, the polarization characteristics of the second polarizer (231) are modulated to have appropriate amplitude and phase characteristics, and the image recorder (310) Recorded as the first spiral phase hologram image (phase shift angle is α = 0), as shown in the lower right of Figure 4A. The image recorder (310) can be placed on the imaging plane or in the non-imaging plane, and the non-imaging plane is at a distance from the imaging plane, which is called the image reconstruction distance (z). In the step (c) of the present invention, the spiral phase generator (210) has a spiral phase plate function, and the same object light wave can be obtained by a spiral phase shift algorithm ( a coded object spectrum of the peripheral high frequency diffraction term of the same object spatial spectrum formed on the spiral phase generator (210) ) for multiple phase shifts. Preferably, it may be a second, three, four or more phase shift. After each phase shift, a spectrum of the encoded object of another phase shift is generated ( ), which has a spectrum with aperture reference light waves ( The optical lens is reversed by the third lens (221) to achieve interference, and another phase-shifted spiral phase hologram image is formed on the image recorder (310). That is, if the phase shift is three times (the phase shift angle is α=π/2, π, 3π/2), a spiral phase hologram image after three phase shifts is generated (excluding the first spiral phase Like image), as shown in the lower right of each of Figures 4B, 4C and 4D. Similarly, it can be seen that after a plurality of phase shifts, a plurality of phase-shifted spiral phase hologram images are generated. In the step (d) of the present invention, the first spiral phase holographic image and the plurality of phase-shifted spiral phase hologram images generated by the plurality of phase shifts are image-reconstructed by the image processor (320). The image reconstruction is completed after the calculation, and can be set at an image reconstruction distance (z) from the image recorder (310) to form a first reconstructed object image having a phase image and an amplitude image. By means of image reconstruction, an image of the object to be tested (50) and a non-imaged reconstructed object image (including amplitude and phase images) can be obtained. The position of the image recorder (310) can be placed in an imaging plane (z = 0) or a non-imaging plane (z ≠ 0). In the step (e) of the present invention, by using a synthetic aperture, the emission source generated by the light source generator (40) is incident on the object to be tested (50) at another angle by rotating the beam deflector (120). Forming another angle of object light waves ( ). That is, rotating the beam deflector (120) to another different angle produces an object light wave at another different angle ( ). Light waves of the object at another angle ( ), again through the above steps (b), (c) and (d), to form an image of the reconstructed object at another angle ( ). That is to say, after the beam deflector (120) performs a series of different angles of rotation along an axis ( x- axis or y- axis), the emission source is incident on the object to be tested (50) at a series of different angles to form a series. Object light waves at different angles ( ), thereby generating a plurality of reconstructed object images at different angles, and the first reconstructed object image ( And the image of the reconstructed object at the plurality of different angles ( The image processor (320) performs a numerical Fourier transform and then superimposes the spectrum thereof, and then performs a numerical inverse Fourier transform to form a reconstructed object image of the synthetic aperture ( ). To further understand the operational process of the present invention, operational symbols and arithmetic expressions are provided below. As described above, in the step (a) of the present invention, an incident light source is incident on an object to be measured (50) by a beam deflector (120) to form an object light wave ( ). Further, in step (b) of the present invention, the spatial spectrum of the light wave of the object is formed by optical Fourier transform of the second lens (220), and the periphery of the concentric circle of the spatial spectrum is a high frequency diffraction of the spatial spectrum formed by the object light wave. item( ), and at the center of the concentric circle, the spectrum of the aperture reference light wave of the low-frequency DC term of the object light wave ( And then modulating the spatial spectrum of the object of the peripheral high-frequency diffraction term through the spiral phase filtering function of the spiral phase generator (210) to form a coded object spectrum ( Filtering the spatial spectrum of the object of the central low-frequency DC term to produce a spectrum of aperture-referenced light waves ( ). In the following expressions, the representation symbols in the space plane are not superscripted, for example: , , , and the representation symbol in the spectrum plane is superscripted, for example: , , , to distinguish. The spiral phase generator (210) is generated using a 矽-based liquid crystal spatial light modulator, and has the expression s ( r , φ )= r exp( iφ ), wherein the radial polar coordinate is r , φ represents the phase change value from 0 to 2π. The encoded object spectrum ( And the spectrum of the aperture reference light wave ( The third lens (221) is used for optical inverse Fourier transform, and the interference between the two is represented in the spatial plane as Forming a first spiral phase hologram image. Step (c) of the present invention, the object light wave ( Repeating step (b) and spectruming the encoded object ( And the spectrum of the aperture reference light wave ( After a plurality of phase shifts, a plurality of phase-shifted spiral phase hologram images are formed, wherein the encoded object light waves are represented in the spatial plane as , the convolution operation is the symbol U, and the spiral phase filter is subjected to inverse Fourier transform ( The result is S , ie , the phase shift angle of the spiral phase filter is Where q is the total number of phase shifts, and p is an integer between 0 and q -1. In the step (d) of the present invention, the first spiral phase holographic image and the plurality of phase-shifted spiral phase hologram images generated by the plurality of phase shifts are image-reconstructed by the image processor (320). After the operation, the image reconstruction is completed, and the image of the object to be tested (50) and the image of the reconstructed object (including the amplitude and phase images) of the object to be measured are obtained. In the step (e) of the present invention, a beam deflector (120) of a synthetic aperture device is used to perform a series of different angles of incidence on the object to be tested (50), and the plane wave of the emission source is considered to be along the xy axis. Scanning, the object light wave will interact with the spiral phase filter and is expressed as follows: (1) The high-frequency diffraction term of the spatial spectrum formed by the object's light wave on the Fourier plane is ( ), and the total scanning angle order is M and N , the order m and n represent an integer between 1 and M and N , the spiral phase filter is s , and the angle between the plane wave and the propagation direction can be represented by the direction cosine for versus The transfer function of the optical system is a circular aperture Said that the cutoff frequency is . Then, the high frequency diffraction term of the spatial spectrum formed by the object light wave ( The encoded object spectrum formed by optical inverse Fourier transform via the third lens (221) )It can be expressed as: (2) Considering that when the object light is diffracted by a distance z to an imaging or non-imaging plane, it can be expressed according to the Fresnel-Kirchhoff diffraction formula: (3) wherein the spiral phase digital hologram image after the phase shift of the spiral phase generator (210) is And then using the imaging device to record the representation of the holographic image as: (4) and using the complex average method to obtain the light wave of the object is as follows: (5) The conjugate complex of the reference light is The spiral phase function opposite to the phase shift direction is , will be used to reconstruct the image of the diffracted object. The convolution algorithm is used to numerically focus the image of the diffracted object as follows: (6) Finally, the reconstructed object images of the multiple tilt angles scanned along the xy axis are respectively subjected to numerical Fourier transform, and the spectrum is superimposed as follows: (7) A reconstructed object image of a synthetic aperture having high spatial resolution and phase accuracy is obtained by the above-described image processor. In an embodiment, when the beam deflector (120) is rotated by an angle, the rotation angle after passing through the first objective lens group (140) is made to be incident on the object to be tested according to the magnification of the first objective lens group (=83 times). The angle of (50) is magnified 83 times the angle of rotation of the beam bender (120). Referring to Figure 2, there is schematically illustrated light waves of objects at different angles ( After the optical Fourier transform of the second lens (220), the spatial spectrum of the object will form a different spectral range on the spiral phase generator (210). The peripheral high frequency diffraction term is the encoded object spectrum ( ), with high-frequency information of the object image and undergoing spiral phase modulation, the central low-frequency DC term is the spectrum with the aperture reference light wave ( ), ideally containing only low frequency DC information of the object. Coded object spectrum light wave ( And the spectrum of the aperture reference light wave ( After the optical inverse Fourier transform is performed via the third lens (221), the two achieve interference. In addition, the spiral phase generator (210) used in the present invention is further explained, and the operation of the spiral phase shift algorithm utilizes a superposition of a spiral phase plate (as shown in FIG. 3A) and a blazed grating (shown in FIG. 3B). Fig. 3C is an illustration of the effect of superimposing a spiral phase plate and a blazed grating. 4A, 4B, 4C, and 4D, respectively, the left phase of the spiral phase generator (210) is used to make the phase shift angle of the spiral phase plate α=0, π/2, π, 3π/2, and The blazed grating is superimposed, and the images obtained after the spiral phase shift algorithm in the above manner are shown in the lower right of each of FIGS. 4A, 4B, 4C, and 4D. Figures 5A-5F show the effect of the invention in the image reconstruction section of step (d). 5A and 5D are amplitude images and phase images of an image reconstruction distance (z) of 2.3 cm, respectively. 5B and 5E are amplitude images and phase images with an image reconstruction distance (z) of 4.7 cm, respectively. 5C and 5F are amplitude images and phase images with an image reconstruction distance (z) of 7.1 cm, respectively. Since the reconstructed object image in the step (c) is a complex image having an amplitude and a phase message, image reconstruction at different image reconstruction distances (z) can be achieved according to the two. Complete the digital hologram. 6A is an amplitude image obtained by a phase shift of a helical phase shift algorithm but not by a synthetic aperture method; FIG. 6B is a three-dimensional contour image obtained by a phase shift of a helical phase shift algorithm but not by a synthetic aperture method; 6C is a measurement result graph for quantifying the cross-section of the three-dimensional contour image of the area to be measured according to the images of FIGS. 6A and 6B, which shows the depth of the hole (ie, the step height, or step height) of about 181 nm. 6D is an amplitude image obtained by a phase shift of a helical phase shift algorithm and also obtained by a synthetic aperture method; FIG. 6E is a three-dimensional contour image obtained by a phase shift of a helical phase shift algorithm and also obtained by a synthetic aperture method; 6F is a measurement result graph for quantifying the cross-section of the three-dimensional contour image of the area to be measured according to the images of FIGS. 6D and 6E, which shows the depth of the hole (ie, the step height, or step height) of about 180 nm. Comparing Fig. 6C and Fig. 6F, the standard deviation of the phase measurement is reduced from about σ≈±8.8 nm to about σ≈±4.0 nm, which shows the phase accuracy of the digital hologram obtained by the spiral phase shift method and the synthetic aperture method. Increase about 2 times. 7A-7F are measurements for the distance (line width) between the score line and the score line on the test piece of Fig. 7G. The respective intervals (line width) of the upper right and lower right scribe lines in Fig. 7G are 320 nm and 282 nm, respectively. 7A and FIG. 7B are amplitude images of the digital hologram of the test piece of FIG. 7G obtained by using the helical phase shift, and the synthetic aperture method and the helical phase shift, respectively; 7A and FIG. 7B show that the spatial resolution of the digital hologram obtained by the latter is relatively high, and the original graphic can be clearly displayed. 7C is a result of quantitative analysis of the line width in the amplitude image of FIGS. 7A and 7B. The red dotted line portion is a measurement result obtained when the synthetic aperture and the spiral phase displacement are shared, and the comparison is performed on the test piece of FIG. 7G. The position of the line is correctly reflected, which means that the spatial resolution of the digital hologram using the synthetic aperture method and the helical phase shift is better. Similarly, FIG. 7D and FIG. 7E respectively obtain the phase image of the digital hologram of the test piece of FIG. 7G using only the spiral phase shift method, and jointly obtain the digital hologram of the test piece of FIG. 7G by using the synthetic aperture method and the spiral phase shift method. Phase image. 7F is a result of phase image quantization analysis of FIG. 7D and FIG. 7E. The red dotted line portion is a measurement result obtained when the synthetic aperture and the helical phase shift are shared (ie, FIG. 7E), which is more capable of the test piece of FIG. 7G. The position of the reticle is correctly reflected, and the digital hologram obtained by the combination of the synthetic aperture and the helical phase displacement has better spatial resolution. Embodiments and effects of the present invention have been described by the above specific embodiments. The above-described embodiments are intended to be illustrative only, and any substitutions, modifications, and variations of the invention may be made by those of ordinary skill in the art. These changes are intended to be encompassed within the scope of the invention.