An edge-lit volume holographic optical element for an objective turret in a lensless digital holographic microscope

Abstract

In this paper, we propose and demonstrate the use of an edge-lit volume holographic optical element (EL-VHOE) as a reference waveguide to reduce the volume of a lensless digital holographic microscope. Additionally, a hybrid lensless Fourier transform digital holography is applied to make the EL-VHOE function as an objective turret. It used a spherical wave in the object beam of the EL-VHOE, which served as the reference beam of the microscope. Another sheared spherical wave was used to illuminate the sample. the longitudinal position of the spherical reference beam is changeable. It was shown that the tradeoff between resolution and field of view can be adjusted by changing the longitudinal position of the spherical reference beam. the corresponding experimental results matched the simulational and theoretical predictions. A resolution of approximately 3.11 μm was achieved when the object distance was 6 mm and the longitudinal distance of the spherical reference was 10 mm.

Development of lens-free holographic microscopes using multiheight and multispectral phase recovery methods

“…# -------------Libraries ---------------------# import cv2 # Library for image processing import numpy as np # Library for math import os # Library for organizing archives from matplotlib import pyplot as plt # Library for display imgs import time # Library for time counting # -------------Functions ---------------------# # Function to rescale an image def rescale(img, scale_factor): width = img.shape [1] ImgScale = scale_factor/width newX, newY = img.shape [1]*ImgScale, img.shape[0]*ImgScale image = cv2.resize(img,(int(newX),int(newY))) Height,Width = image.shape return image, ImgScale # Global variables that are used on the click_and_crop function refPt = [] # vector to save the selected reference coordinates cropping = False # click_and_crop shows an image and saves the reference coordinates of the user-drawn rectangle def click_and_crop(event, x, y, flags, param): global refPt, cropping # event is a user action if event == cv2.EVENT_LBUTTONDOWN: # reference initial coordinate set on the user click with refPt = [(x,y)] # left mouse button cropping = True elif event == cv2.EVENT_LBUTTONUP: # reference final coordinate set on the user click with refPt.append((x,y)) # left mouse button cropping = False # draw a retangle with the reference coordinates cv2.rectangle(image, refPt[0], refPt [1], (0, 255, 0), 2) cv2.imshow("image", image) # load_images opens the selected folder and returns a list with all images that it has inside def load_images ( 16) TransLvl = int(camera_parameter["TRANS_LVL"]) cfg = {"u32CameraType":0x4D091031, "u32Width":Width,"u32Height":Height, "usbType":0, "u8PixelBytes":ByteLength, "u16Vid":0, "u32Size":0, "u8PixelBits":BitWidth, "u32I2cAddr":I2cAddr, "emI2cMode":I2CMode, "emImageFmtMode":FmtMode, "u32TransLvl": '''print("Serial: %d%d%d%d-%d%d%d%d-%d%d%d%d"%(datas[0],datas [1],datas [2],datas [3], datas [4],datas [5],datas [6],datas [7], datas [8],datas [9],datas [10],datas [11])) ------------------------…”

“…# Library for image processing import numpy as np # Library for math import os # Library for organizing archives from matplotlib import pyplot as plt # Library for display images import time # Library for time counting '''print("Serial: %d%d%d%d-%d%d%d%d-%d%d%d%d"%(datas[0],datas [1],datas [2],datas [3], datas [4],datas [5],datas [6],datas [7], datas [8],datas [9],datas [10],datas [11] [1], exposure_time [2])) print('------------------------------------------------\n') ------------------------------------------------\n') # ------------Main function -------------------- if not flag_capture_error: folder = str(input("Insert folder name:"))…”