Beyond pixel number: Where next for endoscopic imaging capabilities?

Filtering multiple wavelengths

Multi-spectral imaging for new diagnostic capabilities is another area of innovation. Most visible light colour cameras use a Bayer filter (a checkerboard of 1 red, 2 green and 1 blue filter) sitting in front of the colour-blind silicon sensor, and ‘demosaicing’ algorithms estimate the actual colour of the image at each pixel.

Strobing on multiple useful wavelengths

To get around this limitation, one can use a greyscale camera and sequential images of the scene by strobing on red-only light, green-only light, blue-only light, and indeed any other useful wavelength of light. Software is then used to add up the frames to produce a multispectral colour image.

The resolution Catch 22

If the full resolution of the sensor can now be used, can the optics keep up? The first limitation is diffraction, where the detail of the image on the sensor is dependent on the aperture diameter of the optics — a smaller diameter means a larger spot size on the detector, meaning less detail, which can negate increases in pixel density.

Software solutions

Rather than relying on the optical hardware to push resolution, other techniques such as software and artificial intelligence could potentially come to the rescue. The limits of resolution described above assume no prior knowledge of the scene, and that every frame is independent of any other frame. In other words, the system has no memory.

Disposable endoscopes?

Within the constraints of endoscope diameter, enhanced imaging capability is thus becoming an important technological battleground for endoscope manufacturers. Another parallel trend is the rise of disposable endoscopes, which avoid laborious and sometimes imperfect sterilisation between deployments.



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TTP — The Technology Partnership

TTP — The Technology Partnership

TTP is an independent technology company where scientists and engineers collaborate to invent, design and develop new products and technologies.