Optics and Image Formation Quiz
93 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What does an image require to be formed in optics?

  • Light to be absorbed completely
  • Only a dark environment
  • A lens that is not converging
  • Light reflected from an object (correct)

The Gaussian lens equation indicates that the focal length is independent of the wavelength.

False (B)

What is the term used to describe distances where objects are imaged with acceptable sharpness?

Depth of Field

What is the mean diameter of the optic disk in a typical human eye?

<p>1800 μm (A)</p> Signup and view all the answers

In basic optics, the center-to-center distance between sensor locations equals the reciprocal of the spatial sampling ______.

<p>frequency</p> Signup and view all the answers

Which of the following arrangements can focus light to a sharp image?

<p>A converging lens (D)</p> Signup and view all the answers

The resolution limit of a typical human eye is based on a 3 mm pupil.

<p>False (B)</p> Signup and view all the answers

Aliasing in spatial sampling is often noticed with periodic patterns.

<p>True (A)</p> Signup and view all the answers

What is the main function of the focal plane array (FPA) in a camera eye model?

<p>To capture and display images from the optical system.</p> Signup and view all the answers

The EC-Eye stands for __________ eye.

<p>Electrochemical</p> Signup and view all the answers

Match the terms with their definitions:

<p>Spatial Sampling Frequency = Distance between sensor locations in imaging Focal Length = Distance over which light rays converge Depth of Field = Axial distance over which imaging is sharp Aliasing = Distortion of periodic patterns in an image</p> Signup and view all the answers

What is the minimum object distance for designers according to the Gaussian lens equation?

<p>100 times the focal length</p> Signup and view all the answers

What is likely the focal length of most standard cameras?

<p>Fixed (C)</p> Signup and view all the answers

The optic disk subtends an arc of roughly 6.2°.

<p>True (A)</p> Signup and view all the answers

Match the following components with their characteristics:

<p>Optic Disk = Mean diameter of 1800 μm Focal Plane Array = Rigidly attached to sensor frame Camera Lens = Fixed focal length EC-Eye = A biomimetic electrochemical eye</p> Signup and view all the answers

What is the significance of the optical center of the lens in the camera eye model?

<p>To adjust the image distance for particular object distances.</p> Signup and view all the answers

What is the primary modular vision unit of the compound eye called?

<p>Ommatidium (D)</p> Signup and view all the answers

Compound eyes provide a narrow field of view.

<p>False (B)</p> Signup and view all the answers

Name the three basic insect vision configurations.

<p>Apposition, superposition, neural superposition</p> Signup and view all the answers

The angle between adjacent ommatidia in a compound eye ranges from ___ to ___ degrees.

<p>1, 2</p> Signup and view all the answers

What is the function of the rhabdom in the compound eye?

<p>Transmitting light to rhabdomeres (D)</p> Signup and view all the answers

Match the following components of the compound eye with their functions:

<p>Ommatidium = Primary modular vision unit Crystalline cone = Focuses light Rhabdom = Channels light to rhabdomeres Facet lens = Allows light entry</p> Signup and view all the answers

Optical flow refers to the apparent motion of surfaces or objects in a scene.

<p>True (A)</p> Signup and view all the answers

What is the primary role of center-surround motion-detection neurons in the compound eye's visual processing?

<p>To detect direction and orientation of motion</p> Signup and view all the answers

What does the control circuit do in the sensing process of a CCD camera?

<p>Causes capacitors to transfer their contents (D)</p> Signup and view all the answers

The Bayer filter mosaic consists of equal amounts of red, green, and blue filters.

<p>False (B)</p> Signup and view all the answers

What type of animal eyes are known as noncompound eyes?

<p>Refractive cornea eye (Camera eye)</p> Signup and view all the answers

A primary refractive power in the camera eye is provided by the _____ interface.

<p>air/cornea</p> Signup and view all the answers

Match the following types of eyes with their categories:

<p>Camera eye = Noncompound eye Apposition eye = Compound eye Optical superposition eye = Compound eye Neural superposition eye = Compound eye</p> Signup and view all the answers

Which element in a CCD camera is responsible for converting charge into voltage?

<p>Charge amplifier (B)</p> Signup and view all the answers

Nearly all mammals have a compound eye structure.

<p>False (B)</p> Signup and view all the answers

What lens do humans use to accommodate focus for close objects?

<p>Variable-shape crystalline lens</p> Signup and view all the answers

Which model uses first and second derivatives to determine velocity?

<p>Differential-based model (B)</p> Signup and view all the answers

Phase-based models utilize an array of filters that analyze incoming signals based solely on orientation.

<p>False (B)</p> Signup and view all the answers

What is one feature of the mantis shrimp's vision?

<p>Polarization vision</p> Signup and view all the answers

The Hassenstein-Reinhardt model is primarily concerned with __________ processing.

<p>motion</p> Signup and view all the answers

Match the following visual processing techniques with their descriptions:

<p>Differential-based models = Use first and second derivatives to determine velocity Energy-based methods = Quantify output energy from velocity tuned Gabor filters Phase-based models = Employ an array of band-pass filters to parse incoming signals Feature-based matching = Determine movement between adjacent temporal image scenes</p> Signup and view all the answers

Which of the following best describes the capabilities of fly eye sensors?

<p>Ideal neural superposition (C)</p> Signup and view all the answers

Energy-based methods utilize frequency outcomes from filters that are tuned for velocity.

<p>True (A)</p> Signup and view all the answers

Mantis shrimp can adjust __________ contrast in their field of view in real time.

<p>polarization</p> Signup and view all the answers

What is a common challenge associated with depth cameras?

<p>Segmentation (A)</p> Signup and view all the answers

Artificial hair cells mimic the sound conversion process of inner hair cells.

<p>True (A)</p> Signup and view all the answers

What frequency range does human hearing typically cover?

<p>20 Hz to 20 kHz</p> Signup and view all the answers

The tympanic membrane consists of three parts: malleus, pars tensa, and __________.

<p>pars flaccida</p> Signup and view all the answers

Match the following components to their functions:

<p>Artificial hair cells = Sound conversion into an electric signal Tympanic membrane = Transmits pressure force from sound Depth cameras = Capture 3D images MEMS technology = Self-sensing and self-actuated systems</p> Signup and view all the answers

Which technology is used in artificial hair cells for sound detection?

<p>MEMS technology (C)</p> Signup and view all the answers

The tympanic membrane moves like a typical diaphragm.

<p>False (B)</p> Signup and view all the answers

What are the two types of cameras mentioned as solutions for depth imaging?

<p>Two or more cameras and time-of-flight cameras</p> Signup and view all the answers

What does the Optical Transfer Function (OTF) represent?

<p>The Fourier transform of the Point Spread Function (D)</p> Signup and view all the answers

The Modulation Transfer Function (MTF) indicates how well a system can transfer contrast at different spatial frequencies.

<p>True (A)</p> Signup and view all the answers

What is the main issue described by the phenomenon of blooming in CCD cameras?

<p>Overflow of too many electrons</p> Signup and view all the answers

Quantum efficiency of a typical CCD camera is around _____%.

<p>70</p> Signup and view all the answers

Match the following optical terms with their definitions:

<p>PSF = Describes how a point of light is spread by an optical component OTF = Fourier transform of the Point Spread Function MTF = Magnitude of the Optical Transfer Function CTF = Describes contrast transfer in line pairs</p> Signup and view all the answers

Which wavelength of light does NOT generate electrons in a CCD sensor?

<p>Infrared light (B)</p> Signup and view all the answers

All CCD cameras utilize additional devices like AD converters and amplifiers.

<p>False (B)</p> Signup and view all the answers

What is the photoactive region in a CCD camera responsible for?

<p>Generating free electrons from incoming photons</p> Signup and view all the answers

Which feature of the compound eye helps in depth perception?

<p>Stereo vision (D)</p> Signup and view all the answers

The interommatidial angle in a compound eye typically ranges from 1 to 3 degrees.

<p>False (B)</p> Signup and view all the answers

What is the primary modular vision unit of the compound eye?

<p>Ommatidium</p> Signup and view all the answers

The apparent motion of surfaces or objects in a scene is referred to as __________.

<p>Optical flow</p> Signup and view all the answers

Match the following types of insect vision configurations with the correct description:

<p>Apposition = Type of vision where light from adjacent ommatidia is not merged Superposition = Type of vision that allows for enhanced sensitivity in low light Neural superposition = Involves combining signals from adjacent ommatidia Neural configuration = Refers to the neural processing of visual information</p> Signup and view all the answers

What is the role of the crystalline cone in the compound eye?

<p>Focusing light on the rhabdom (A)</p> Signup and view all the answers

Primitive forms of object recognition take place in the compound eye's brain.

<p>False (B)</p> Signup and view all the answers

What channels the light to the photosensitive receptors in the compound eye?

<p>Rhabdom</p> Signup and view all the answers

What is the effect of a longer focal length lens for a given aperture on depth of field (DOF)?

<p>Smaller DOF (C)</p> Signup and view all the answers

The angular field of view is affected by the distance of the object being observed.

<p>False (B)</p> Signup and view all the answers

What does Snell's law predict?

<p>The angle of refraction</p> Signup and view all the answers

Reflectance (R) plus Transmittance (T) is equal to ____.

<p>1</p> Signup and view all the answers

What effect does aperture size have on image quality?

<p>It introduces blur spots (D)</p> Signup and view all the answers

Which type of aberration considers only one wavelength at a time?

<p>Monochromatic aberration (A)</p> Signup and view all the answers

Match the following refractive indices with their materials:

<p>Air = 1 Crown glass = 1.5 Water = 1.33 Diamond = 2.42</p> Signup and view all the answers

Aliasing occurs when spatial frequencies exceed half the spatial sampling frequency.

<p>True (A)</p> Signup and view all the answers

What is the primary function of the charge amplifier in a CCD camera?

<p>Convert charge into voltage (B)</p> Signup and view all the answers

Chromatic aberration appears as inappropriate color fringes along edges in a color image.

<p>True (A)</p> Signup and view all the answers

The distance over which objects are imaged with acceptable sharpness is known as the ___ of field.

<p>depth</p> Signup and view all the answers

What is the primary cause of most monochromatic aberrations in lenses?

<p>Imperfections in lenses</p> Signup and view all the answers

Name one type of compound eye.

<p>Apposition eye or optical superposition eye or neural superposition eye</p> Signup and view all the answers

The primary refractive power in the camera eye is due to the _______ interface.

<p>air/cornea</p> Signup and view all the answers

Match the following types of eyes with their characteristics:

<p>Noncompound Eye = Refractive cornea eye (Camera eye) Compound Eye = Apposition eye Camera Eye = Includes internal lens for focus Optical Superposition Eye = Multiple lens arrangement to gather light</p> Signup and view all the answers

What is one primary reason for using bioinspired vision sensor technologies?

<p>To utilize characteristics from biological systems for improved performance (A)</p> Signup and view all the answers

Which of the following are the two main groups of animal eyes?

<p>Noncompound and compound eyes (C)</p> Signup and view all the answers

What is the term used for the perceived motion of objects in a scene due to observer movement?

<p>optical flow</p> Signup and view all the answers

Human hearing typically covers a frequency range of 20 Hz to 20 kHz.

<p>True (A)</p> Signup and view all the answers

Humans possess a compound eye structure.

<p>False (B)</p> Signup and view all the answers

What allows the human eye to accommodate focus for close objects?

<p>Variable-shape crystalline lens</p> Signup and view all the answers

What are the two main types of biomimetic eyes?

<p>Compound eyes and simple eyes (B)</p> Signup and view all the answers

Biomimetic eyes are limited to only one structural design.

<p>False (B)</p> Signup and view all the answers

What is the concept of compound eyes?

<p>Compound eyes consist of multiple small visual units called ommatidia, each capturing a portion of the visual field.</p> Signup and view all the answers

The three primary insect vision configurations are ______, _______, and _______ vision.

<p>apposition, superposition, and mosaic</p> Signup and view all the answers

Match the following insect vision configurations with their descriptions:

<p>Apposition vision = Transmits direct light to achieve high acuity Superposition vision = Combines light from multiple ommatidia for low light conditions Mosaic vision = Perceives images as a collection of segmented visual inputs</p> Signup and view all the answers

How can motion hyperacuity be achieved?

<p>Through specialized neural processing (B)</p> Signup and view all the answers

Biomimetic hair cells are developed to mimic the ________ cells in natural hearing.

<p>inner hair</p> Signup and view all the answers

A biomimetic basilar membrane sensor functions similarly to the natural basilar membrane in the cochlea.

<p>True (A)</p> Signup and view all the answers

Flashcards

Image Formation

The process of forming an image by focusing light reflected from an object onto a surface.

Converging Lens

A converging lens or system of lenses that creates the sharpest image by focusing light.

Object Distance (so)

The distance between the object and the lens.

Image Plane Distance (si)

The distance between the lens and the image plane where the image forms.

Signup and view all the flashcards

Focal Length (f)

A fixed property of a lens that determines its focusing power. It's a measure of how strongly the lens converges light.

Signup and view all the flashcards

Gaussian Lens Equation

A relationship between object distance (so), image plane distance (si), and focal length (f) describing how light is focused.

Signup and view all the flashcards

Spatial Sampling Distance

The distance between the centers of adjacent sensors on an image capturing device.

Signup and view all the flashcards

Sampling Theorem

The ability to capture and reconstruct information from an image without losing details due to limitations in the sampling process.

Signup and view all the flashcards

CCD Image Sensing

A method used by CCD (Charge-Coupled Device) sensors to convert an image into electrical signals.

Signup and view all the flashcards

Bayer Filter Mosaic

A color filter pattern used in CCD cameras to capture red, green, and blue light.

Signup and view all the flashcards

Camera Eye

A type of eye found in mammals, humans, and cephalopods, characterized by a single lens that focuses light onto a retina.

Signup and view all the flashcards

Cornea

The curved, transparent surface of the eye that bends light. It contributes significantly to focusing.

Signup and view all the flashcards

Crystalline Lens

A structure inside the eye that further focuses light onto the retina. It adjusts its shape to focus on objects at different distances.

Signup and view all the flashcards

Helmholtz's Schematic Eye

A simplified model of the human eye that represents it as a single refractive surface. It helps in understanding the optics of the eye.

Signup and view all the flashcards

Posterior Nodal Distance

The distance from the lens to the point where light converges on the retina. It is often used in simplified eye models.

Signup and view all the flashcards

Aperture

A term that describes how well the eye gathers light, allowing clear vision in low light conditions.

Signup and view all the flashcards

Biomimicry

The process of using biological systems as inspiration for designing and developing new technologies.

Signup and view all the flashcards

Optic Disk

A structure in the human eye responsible for transmitting visual information to the brain.

Signup and view all the flashcards

Resolution Limit

The smallest detail that can be distinguished by the human eye.

Signup and view all the flashcards

Focal Plane Array (FPA)

A device used in cameras and vision sensors that captures light and converts it into an image.

Signup and view all the flashcards

Focal Length

The distance between the lens and the image sensor in a camera.

Signup and view all the flashcards

EC-Eye

A camera inspired by the human eye, featuring a hemispherical perovskite nanowire array retina.

Signup and view all the flashcards

Biomimetic Material

A type of material that mimics the structure and properties of biological materials.

Signup and view all the flashcards

Adjustable Focus Camera

A camera technology that allows for adjustable focus by moving the lens.

Signup and view all the flashcards

Compound eye

A type of eye found in many insects and other species, consisting of multiple individual light-sensitive units called ommatidia.

Signup and view all the flashcards

Ommatidium

The primary modular vision unit of a compound eye, responsible for receiving and processing light.

Signup and view all the flashcards

Interommatidial angle

The angle between adjacent ommatidia in a compound eye, determining the resolution and field of view.

Signup and view all the flashcards

Crystalline cone

A transparent structure within an ommatidium that focuses light onto the rhabdom.

Signup and view all the flashcards

Rhabdom

A light-sensitive structure within an ommatidium, responsible for converting light into electrical signals.

Signup and view all the flashcards

Apposition eye

A type of vision where each ommatidium functions independently, resulting in a mosaic image.

Signup and view all the flashcards

Optical flow

The apparent motion of surfaces or objects in a scene, resulting from the motion difference between the observer and a scene.

Signup and view all the flashcards

Center-surround motion-detection neuron

A type of neuron that detects motion in a specific direction.

Signup and view all the flashcards

Differential-based Motion Models

Models that use the difference in brightness between neighboring pixels to determine an object's velocity. They use calculations based on first and second derivatives.

Signup and view all the flashcards

Region-based Motion Models

Models that determine object movement by comparing features (e.g., edges, shapes) between consecutive images.

Signup and view all the flashcards

Phase-based Motion Models

Models that utilize a range of filters to analyze the incoming signal based on scale, speed, and orientation, allowing them to determine motion.

Signup and view all the flashcards

Energy-based Motion Models

Model that uses the energy produced by velocity-tuned Gabor filters to quantify motion. It measures how much 'work' is done to detect movement.

Signup and view all the flashcards

Hassenstein-Reinhardt Model

A model that explains how certain insects perceive movement, highlighting the role of sensory input from their compound eyes.

Signup and view all the flashcards

Fly Eye Sensors

Specialized sensors inspired by the structure of insect eyes. They are biologically inspired and designed to mimic features like the compound eye.

Signup and view all the flashcards

Motion Hyperacuity

A phenomenon where fly eye sensors demonstrate exceptional accuracy in detecting motion, even very subtle movements.

Signup and view all the flashcards

Adaptive Contrast Vision

A biological system that allows mantis shrimp to see both colors and polarization of light, providing them with highly detailed visual information.

Signup and view all the flashcards

Depth Camera

A type of camera that measures the distance to objects in a scene by emitting light and measuring the time it takes to return.

Signup and view all the flashcards

Multi-Camera Depth System

A depth camera that uses multiple cameras to capture images from different angles and calculate depth.

Signup and view all the flashcards

Holes in Depth Map

Depth cameras can suffer from holes in the depth map, which are areas where the camera cannot measure depth accurately.

Signup and view all the flashcards

Segmentation (in Depth Cameras)

The process of identifying and separating objects in a scene from the background.

Signup and view all the flashcards

Artificial Hair Cells

The human ear's ability to detect sound is based on the movement of tiny hair cells inside the inner ear.

Signup and view all the flashcards

Self-Sensing Cantilever

The ability to measure extremely small forces, like the vibrations of a hair cell.

Signup and view all the flashcards

Tympanic Membrane (TM)

The thin membrane in the middle ear that vibrates in response to sound waves.

Signup and view all the flashcards

Non-Diaphragmatic Movement of TM

The TM does not move as a flat diaphragm, but rather has a specific movement pattern due to the pressure distribution.

Signup and view all the flashcards

Field of View (FOV)

The range of a scene that can be captured by a lens. Typically, it is not dependent on the aperture size.

Signup and view all the flashcards

Depth of Field (DOF)

The distance over which objects appear sharp in an image. It is directly related to aperture size and focal length.

Signup and view all the flashcards

Refraction

The bending of light as it passes from one medium to another, for example from air to glass. This is what makes lenses focus light.

Signup and view all the flashcards

Index of Refraction (n)

The ratio of the speed of light in a vacuum to the speed of light in a given medium. It is a measure of how much light is slowed down as it passes through a material.

Signup and view all the flashcards

Chromatic Aberration

An imperfection in a lens that can distort images. It is the inability of a lens to focus all wavelengths of light at the same point.

Signup and view all the flashcards

Monochromatic Aberration

An imperfection in a lens that can distort images. It is caused by the lens not focusing all points of an object at the same distance.

Signup and view all the flashcards

Point Spread Function (PSF)

A measure of how well an optical component spreads or smears an infinitesimally small point of light at its focal plane.

Signup and view all the flashcards

Optical Transfer Function (OTF)

The Fourier transform of the Point Spread Function (PSF). It describes how different spatial frequencies are affected by an optical system.

Signup and view all the flashcards

Modulation Transfer Function (MTF)

The magnitude of the Optical Transfer Function (OTF). It quantifies how much contrast an optical system preserves for different spatial frequencies.

Signup and view all the flashcards

Contrast Transfer Function (CTF)

The ratio of the contrast in the image to the contrast in the object for a line pair pattern. It measures how well an optical system can reproduce fine details.

Signup and view all the flashcards

Blooming (CCD)

An overflow of electrons in the photoactive region of a CCD sensor, leading to a bright streak or 'blooming' in the captured image.

Signup and view all the flashcards

Quantum Efficiency (CCD)

The efficiency of a CCD sensor in converting incoming photons into free electrons. It's usually measured as a percentage.

Signup and view all the flashcards

Optical Superposition eye

A type of compound eye where light from multiple ommatidia is combined before reaching the photoreceptor cells.

Signup and view all the flashcards

Neural Superposition eye

A type of compound eye where the signals from multiple ommatidia are integrated at the neural level.

Signup and view all the flashcards

Early Visual Processing in Compound Eyes

A process that occurs in the compound eye, where primitive forms of object recognition take place on the retina itself before reaching the brain. It allows for quick and efficient visual processing.

Signup and view all the flashcards

Biomimetic Vision Sensors

Biomimetic vision sensors mimic the structure and function of biological eyes, drawing inspiration from natural systems.

Signup and view all the flashcards

Types of Biomimetic Eyes

The two main types of eyes found in nature are "camera eyes" and "compound eyes". Camera eyes have a single lens that focuses light onto a retina, like in humans and cephalopods. Compound eyes, common in insects, are composed of numerous individual light-sensitive units called ommatidia, providing a mosaic image.

Signup and view all the flashcards

Advantages of Camera vs Compound Eye

Camera eyes are well-suited for long-distance vision and high-resolution imaging, while compound eyes are ideal for detecting motion, tracking objects in a wide field of view, and providing excellent sensitivity in low light conditions.

Signup and view all the flashcards

Concept of Compound Eyes

Compound eyes are made of multiple light-sensitive units called "ommatidia". Each ommatidium functions independently, creating a mosaic image. This design allows for wide field of view and sensitivity to movement.

Signup and view all the flashcards

Insect Vision Configurations

Insect vision can be categorized into three primary configurations: * Apposition eye: Each ommatidium works independently, forming a mosaic image. * Superposition eye: Light from multiple ommatidia is superimposed on a single receptor. * Neural superposition eye: Signals from multiple ommatidia are combined and processed in the nervous system.

Signup and view all the flashcards

Biomimetic Hair Cells

Biomimetic hair cells replicate the structure and function of hair cells in the inner ear. They are used to detect sound waves and convert them into electrical signals.

Signup and view all the flashcards

Biomimetic Basilar Membrane Sensor

A biomimetic basilar membrane sensor is a device that mimics the auditory system's use of a flexible membrane, the basilar membrane, to detect and distinguish different frequencies of sound.

Signup and view all the flashcards

Study Notes

Pázmány Péter Catholic University

  • Faculty of Information Technology and Bionics

Lecture 6: Biomimetic and Bioinspired Sensors: Vision, Hearing

  • November 6th, 2024
  • Presented by Dr. Sándor Földi
  • Focuses on sensor technologies and biological sensing

Contents

  • Optics
  • Physiology of vision
  • Classic camera
  • Bioinspired vision sensor technologies
  • Depth camera
  • Physiology of hearing
  • Bioinspired hearing sensor

Basic Optics

  • Image formation: Light reflected from an object/scene focuses on an image plane.
  • Camera sensors: Located at the image plane.
  • Sharpest image: Created with a converging lens or system of lenses.
  • Gaussian lens equation: 1/So + 1/Si = 1/f (where So = object distance, Si = image distance, f = focal length)
  • Focal length and other optical parameters depend on wavelength.
  • Optical infinity: Object distance resulting in image plane distance close to focal length (So ≥ 100f).
  • Visual acuity exams: So ≈ 338f
  • Spatial sampling: Center-to-center distance between sensor locations equals the reciprocal of spatial sampling frequency.
  • Sampling theorem: Limits spatial frequencies that can be sampled and reconstructed without aliasing.
  • Aliasing: Noticable in periodic patterns (e.g., stripes), causing them to appear broader and distorted.
  • Aperture Size: Lenses cannot focus light to infinitely small points, resulting in blur spots.
  • Effective aperture size: Diameter, numerical aperture (microscopy), f-number.
  • Depth of Field (DOF): Axial distance over which objects are imaged with acceptable sharpness.
  • DOF is smaller with larger apertures.
  • Longer focal length lenses result in a smaller DOF for a given aperture.
  • Field of view: Span over which a given scene is imaged.
  • FOV determined by geometry, independent of object distance.
  • For a sensor of size 'a', angular FOV = 2arctan(a/2f).
  • Reflection and refraction: Light encountering a boundary with different refractive indices changes direction (or reflects).
  • Snell's law: Predicts refraction angles; sinθ₁/n₁ = sinθ₂/n₂
  • Angle of reflection equals the angle of incidence.
  • Reflectance (R) and Transmittance (T): Fraction of incident light intensity reflected or refracted (R + T = 1).
  • Aberrations: Imperfections in lenses, including monochromatic and chromatic.
  • Monochromatic aberrations: Spherical, comma, astigmatism, field curvature, defocus, barrel and pincushion distortion.
  • Chromatic aberration: Multiple wavelengths, refractive index varies with wavelength. Causes fringes of inappropriate color along edges in images.

Fourier Optics

  • Powerful method for design considerations like aperture, lenses, photodetector sizes, and spatial sampling.
  • Point Spread Function (PSF): Describes how a point light source is spread by an optical component.
  • Optical Transfer Function (OTF): Fourier Transform of PSF.
  • Modulation Transfer Function (MTF): Magnitude of OTF
  • Contrast Transfer Function (CTF): Often use line pairs to define maximal frequency sinusoidal pattern.

Recap - Vision

  • Details in Lecture 2.
  • Eye anatomy: Cornea, lens, iris, retina, fovea, optic nerve, and optic disk.

Classic CCD Camera

  • Charge Coupled Device introduced in 1974.
  • Majority of cameras use CCDs.
  • Cheap semiconductor technology, integrated on a chip.
  • Sensor matrix: Discretized pixels, discretization, pixelization.
  • Photons generate electrons. Infrared photons don't, UV photons absorbed early.
  • Quantum efficiency typically around 70%.
  • Free electrons trapped in potential holes (2-100,000 per electron).
  • Blooming: Overflow of electrons.
  • Steps of sensing: Exposure → transfer to neighbor (shift register) → charge amplifier → voltage conversion.

Bayer Filter Mosaic

  • Color filter array (CFA) for arranging RGB color filters in a grid.
  • Half green, one-quarter red and blue each for photosensors.
  • Better color separation with three-CCD devices or beam splitters.

Biomimetic Vision Sensor Approaches

  • Many animal eye variations.
  • Two main groups: Noncompound and Compound.
  • Refractive Cornea eye (Camera eye).
  • Compound eye: Apposition, optical superposition, and neural superposition.

Camera Eye

  • Typical in mammals (including humans).
  • Primary refraction by air/cornea interface.
  • Additional refraction from internal lenses (like crystalline lens in humans), for focus adjustment.
  • Large aperture for light gathering.
  • Artificial systems mimic cornea/lens and focal plane array (FPA).
  • Helmholtz's schematic eye: A simplified model for the human eye (single refractive surface, nodal distance, angular span).

Recap - Ear Structure

  • Ear Anatomy: Auditory canal, tympanic membrane, oval window, malleus, stapes, incus, cochlear nerve, spiral ganglion, cochlea.
  • Outer ear: auditory canal, pinna.
  • Middle ear: malleus, incus, stapes, oval window.
  • Inner ear: cochlea, basilar membrane (spiral organ), and cochlear nerve.

Recap - Organ of Corti

  • Structure of Organ of Corti: Tectorial membrane, outer hair cells, inner hair cells, basilar fiber.

Artificial Hair Cells

  • Technology for mimicking the functionality of hair cells.
  • Design for strain sensors, cantilever-support sensors.

Biomimetic Sound Detection

  • Mimic sound-to-electrical conversion in the inner ear and amplification by outer hair cells.
  • Technologies include MEMS (microelectromechanical systems).
  • Self-sensing and self-actuated cantilevers, feedback control loops to generate electrical signals for amplification.
  • Can use feedback control loops.

Biomimetic Tympanic Membrane

  • Tympanic membrane (TM) structure: malleus, pars tensa, and pars flaccida.
  • TM shape: Curved conical, does not move like a diaphragm.
  • Center of the TM receives response to pressure forces.
  • Materials can be thermo plastic elastomer for durable and flexible diaphragms and polivinyl alcohol as support.

Biomimetic Artificial Basilar Membrane

  • Pseudo-resonant structure adapting to different widths, stiffness, mass and damping values
  • High-frequency sounds impact cochlea's base.
  • Technologies for basilar membrane mimicking: Triboelectric and piezoelectric approaches (e.g., using PZT or AIN).
  • Trapezoidal and beam type models.
  • Flexible Piezoelectric zirconite titanite (PZT) thin film-based approaches.
  • MEMS Piezoelectric aluminum nitride (AIN)-based models.
  • Flexible Piezoelectric polyvinylidene difluoride (PVDF)-based models.

Summary-Questions

  • Key optics concepts in biomimetic vision
  • Types of biomimetic eyes, differences, use-cases.
  • Compound eyes, primary configurations, hyperacuity.
  • Hair cells and hearing, basilar membrane sensor.

References

  • Various cited in the provided pages.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Sensor Technologies and Biological Sensing Lecture 6 PDF

Description

Test your knowledge on key concepts in optics including the Gaussian lens equation, image formation requirements, and the characteristics of the human eye. This quiz covers focal lengths, resolution limits, and spatial sampling in depth. Ideal for students and enthusiasts of optics and imaging technology.

More Like This

Optics: Image Formation by Lenses
5 questions

Optics: Image Formation by Lenses

WarmerManticore avatar
WarmerManticore
Optics and Image Formation
25 questions

Optics and Image Formation

SlickPromethium avatar
SlickPromethium
Optics and Image Formation
38 questions

Optics and Image Formation

SensationalBirch avatar
SensationalBirch
GEOMETRICAL OPTICS
45 questions

GEOMETRICAL OPTICS

BreathtakingBinary924 avatar
BreathtakingBinary924
Use Quizgecko on...
Browser
Open
Browser
Browser