A breakthrough in image digital sensors

Roberto Saracco February 19, 2018 Blog 1,294 Views

The new image sensor allows the reading of all pixels in parallel rather than in sequence as it happens with today’s sensors. Credit: Sony

Image digital sensors are now ubiquitous powering billions and billions of digital cameras, security cameras, video cameras… Over this 43 years since 1975 when the first digital camera was invented by the king of film photography -Kodak- enormous progress have been made. That first digital camera took 50ms to take a picture with a resolution of 10,000 pixels and 23 seconds to store it on a magnetic tape.

The first prototype of the digital camera invented in 1975 da Steven Sasson at Kodak. He tried to convince Kodak that such a technology was the future, the resolution would increase over time and it would even be possible to send digital photos over telecommunications lines. Kodak did not believed him, at least they thought it did not make business sense, which at the time was right. Image credit: Kodak

Today’s sensors can reach hundreds of millions of pixels (in very special applications, 10 million pixels are a given in a smartphone camera). This huge amount of pixels are managed by electronics that transfer the value of each pixel (related to the number of photons captured by that pixel) to the camera computer for the processing that results in the digital photo.

The reading of the pixels occurs sequentially in today’s sensors, row by row. Hence the need for a shutter to stop the incoming of photons as the rows are read.

Sony has announced the creation of a digital image sensor where all pixels can be read in parallel. This is made possible by the association of an Analog to Digital Converter for each pixel. Basically the chip consists of two layers, the first one containing the pixels, sort of buckets collecting photons, and a second one beneath the first with electronics to read the number of photons accrued by that pixel. A first command reset the pixel, a second one read the number of photons captured by the pixel since the reset command.

This approach gets rid of the shutter, no longer needed making construction easer and increasing the performances of the camera.

The sensors built by sone has only 1.46 million pixels, too few to compete with current image sensors but remember that first sensor with 10,000 pixels what has become today. We might expect this new breakthrough technology to evolve rapidly and hit the market in the next decade displacing the current one.

There were already a few comments on the Nikon D850, the top of the line Nikon camera celebrating their 100th anniversary, saying that might be the last camera using a mirror, since the mirror-less camera will take over (getting rid of the optical viewfinder thanks to the increasing performance of contrast detection technology to focus on objects). The Sony chip may provide a further push towards the evolution of cameras with the disappearance of today’s (relatively) bulky DSRL. It can also bring extreme high frame filming into the hand of consumer camera opening up new way of artistic creativity.