Related Experiment Video
Updated: Jun 12, 2026
06:25
Time Multiplexing Super Resolving Technique for Imaging from a Moving Platform
Published on: February 12, 2014
High focal depth by apodization and digital restoration
Applied Optics
|June 10, 2010
Summary
Digital restoration algorithms significantly enhance the defocused optical transfer function of apodized optical systems. This approach enables achieving greater focal depth through a combination of apodization and post-recording digital processing.
Area of Science:
- Optical Engineering
- Digital Image Processing
- Computational Imaging
Background:
- Apodization is used to control the optical transfer function (OTF) of optical systems.
- Defocus significantly degrades image quality by altering the OTF.
- Digital restoration techniques offer potential for post-acquisition image correction.
Purpose of the Study:
- To demonstrate the substantial improvement of a defocused OTF in an apodized optical system using digital restoration.
- To show that combining apodization with digital restoration can achieve high focal depth.
- To validate the achieved focal depth through computer simulations.
Main Methods:
- Utilized iterative digital restoration algorithms, specifically Wiener and Kalman filters.
- Applied apodization during the recording step of the optical system.
- Performed digital restoration as a post-processing step to enhance image quality and focal depth.
Main Results:
- Substantial improvement in the defocused optical transfer function of the apodized optical system was achieved.
- The combined approach of apodization and digital restoration successfully yielded high focal depth.
- Computer simulations confirmed the significant focal depth enhancement.
Conclusions:
- Iterative digital restoration algorithms effectively enhance the OTF of apodized optical systems, even when defocused.
- A high focal depth can be practically achieved by integrating apodization with post-acquisition digital restoration.
- This methodology presents a viable strategy for improving imaging performance in optical systems requiring extended depth of field.
Related Concept Videos
01:16Focusing of Light in the Eye
Light rays enter the eye through the cornea, a transparent dome-shaped tissue that is the eye's outermost layer. The cornea bends or refracts, light rays traveling to the pupil. The shape of the cornea determines how much of the light is bent and whether the image will be focused correctly on the retina at the back of the eye. Once the light has passed through both refraction layers, it converges into a single focal point onto a small area. This is where photoreceptors start transforming...
01:37Super-resolution Fluorescence Microscopy
Super-resolution fluorescence microscopy (SRFM) provides a better resolution than conventional fluorescence microscopy by reducing the point spread function (PSF). PSF is the light intensity distribution from a point that causes it to appear blurred. Due to PSF, each fluorescing point appears bigger than its actual size, and it is the PSF interference of nearby fluorophores that causes the blurred image. Various approaches to achieving higher resolution through SRFM have recently been developed.
01:20Downsampling
When considering a sampled sequence with zero values between sampling instants, one can replace it by taking every N-th value of the sequence. At these integer multiples of N, the original and sampled sequences coincide. This process, known as decimation, involves extracting every N-th sample from a sequence, thereby creating a more efficient sequence.
The Fourier transform of the decimated sequence reveals a combination of scaled and shifted versions of the original spectrum. This...
The Fourier transform of the decimated sequence reveals a combination of scaled and shifted versions of the original spectrum. This...
01:18Imaging Biological Samples with Optical Microscopy
Optical microscopy uses optic principles to provide detailed images of samples. Antonie van Leeuwenhoek designed the first compound optical microscope in the 17th century to visualize blood cells, bacteria, and yeast cells. In 1830, Joseph Jackson Lister created an essentially modern light microscope. The 20th century saw the development of microscopes with enhanced magnification and resolution.
In optical microscopy, the specimen to be viewed is placed on a glass slide and clipped on the stage...
In optical microscopy, the specimen to be viewed is placed on a glass slide and clipped on the stage...
01:26Phase Contrast and Differential Interference Contrast Microscopy
Phase-Contrast Microscopes
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
01:10Reconstruction of Signal using Interpolation
Signal processing techniques are essential for accurately converting continuous signals to digital formats and vice versa. When a continuous signal is sampled with a period T, the resulting sampled signal exhibits replicas of the original spectrum in the frequency domain, spaced at intervals equal to the sampling frequency. To handle this sampled signal, a zero-order hold method can be applied, which creates a piecewise constant signal by retaining each sample's value until the next sampling...