Canon looks to improve on their Dual Slope ADC Sensors
In this patent application Canon discusses some of their problems with dual slope comparator ADC sensors.
What in general this is, is that the analog value is compared against a digital slope, when the two values are equal, the time in which it has taken for the digital slope to get up to to the same value, is the digital value of the analog signal.
Sounds easy? It is. But there's a problem, if you have a scene that has all high light values, each slope comparison on each single pixel takes a longer amount of time,then say for instance if you have alot of dark on the image.
To get around this, and to generally speed up the processing, they implement another slope, which is faster than less precise (less bits) than the longer slope.
This is why on cameras such as the M5, there is two different bit depths, one for quicker FPS the other for slower FPS, or for electronic shutter.
This patent is looking at the fact that dark current in some photography instances will increase, and become significant to the lower precision (faster) slope image taking. They can get around it like they currently do with LENR (Long exposure noise reduction), but they are looking to improve the sensor itself as a better option for imagery.
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