Brain-Inspired Image Sensor can Detect Miniscule Objects

• 22 Feb 2023

Why in News?

A new study at Indian Institue of science (IISc) has shown that a brain-inspired image sensor can go beyond the diffraction limit of light to detect miniscule objects such as cellular components or nanoparticles invisible to current microscopes.

What is this Technology?

• The technique combines optical microscopy with a neuromorphic camera and machine learning algorithms and presents a major step forward in pinpointing objects smaller than 50 nanometers in size.
  • The diffraction limit prevents optical microscopes from distinguishing between two objects smaller than a certain size (typically 200-300 nanometers).
• The neuromorphic camera mimics the way the human retina converts light into electrical impulses.
  • In neuromorphic cameras, each pixel operates independently, generating sparse and lower amount of data. The process is similar to how the human retina works.
    • It allows the camera to “sample” the environment with much higher temporal resolution.
  • In conventional cameras, each pixel captures the intensity of light falling on it and these pixels are pooled together to reconstruct an image of the object.
• The experiment used the neuromorphic camera to pinpoint individual fluorescent beads smaller than the limit of diffraction, by shining laser pulses at both high and low intensities, and measuring the variation in the fluorescence levels.
  • As the intensity increases, the camera captures the signal as an “ON” event, while an “OFF” event is reported when the light intensity decreases.
  • The data from these events were pooled together to reconstruct frames.

What is the Significance of this Technique?

• This approach can have widespread applications in precisely tracking and understanding stochastic processes in biology, chemistry and physics.
  • It will help understand the thumb rules of biological processes like self-organisation.
  • The team was also able to closely track the movement of a fluorescent bead moving freely in an aqueous solution using this technique.

What is a Stochastic process?

• It is a process involving the operation of chance and is also known as Random process.
• For example, in radioactive decay every atom is subject to a fixed probability of breaking down in any given time interval.

What is Diffraction Limit?

• The diffraction limit is a fundamental physical limit on the ability of an optical system to resolve or distinguish between two closely spaced objects.
• The smallest resolvable distance between two-point sources of light is determined by the size of the aperture or lens used to observe the objects, as well as the wavelength of the light being observed.
• In practical terms, this means that even with a perfect lens or telescope, there is a limit to how much detail can be resolved in an image.
• Objects that are closer together than the diffraction limit will appear blurred or indistinguishable in the image.

Source:TH