The high speed cameras make it possible to acquire a fast single event at a fast frame rate and to observe it at a reduced frame rate, the so called “slow motion”. They find many applications in motion analysis, explosives, ballistic, bio-mechanics research, crash test, manufacturing, production line monitoring, deformation, droplet formation, fluid dynamics, particle, spray, shock & vibration, etc. The current industrial most efficient cameras offer a speed of 25,000 frames per second (fps) for a spatial resolution of 1280 x 800 pixels, i.e. 25 Gigapixel/s. This speed is not restricted by the electronics of the pixel but by the sensors chip inputs/outputs interconnections. The conventional operation mode based on extracting the sensor data at each acquisition of a new image is a real technological barrier that limits the scope of high speed cameras.
The DIBIS project main goal is to overcome this technological barrier, increasing the acquisition speed by three orders of magnitude by proposing a sensor capable of taking up to 100 million fps while increasing the sampling rate up to 10 Terapixel/s. Several studies mention the realisation of high-speed image sensors based on the principle of “burst” images (BIS Burst Image Sensor). Since it is impossible to get the frames out of the sensor as they are acquired, the idea is to store all the images in the sensor at a very high data throughput and execute the readout the movie afterwards at a more conventional speed. So far, all the developed BIS based on this principle use a totally analogue approach in the form of a monolithic sensor. The size of the embedded memory is generally limited to a hundred frames, the pixel pitch is around 40 μm and the acquisition rate is in the order of 5 Mfps for large 2D arrays. Furthermore, research works mention that a maximal signal to noise ratio of 45 dB is obtained, the dynamic is thus limited to 8 bits.
The DIBIS (for Digital BIS) project is based on a device concept in total disruption with previous works, by implementing the possibilities offered by the emergent microelectronics 3D technologies in order to increase the performance of this type of sensor while also adding more features to it. The consortium recently demonstrated that the design of a digital BIS is achievable by designing 2 demonstrators with such a new technology. This novel architecture offers new features and performances. The targeted performances are well beyond the state of the art with a spatial resolution of 600 x 900 pixels, an unrivalled dynamic of 12 bits and an on the fly analogue to digital conversion that allows to store more than 500 frames in the digital domain. A binning feature also allow to increase the frame rate from 10 million frames per second at full resolution at up to 100 million frames at reduced spatial resolution. Regarding the applications, the performances breakthrough of the proposed sensor will allow to observe faster phenomenon with unprecedented precision.