Canon has developed a CMOS sensor with “leading” dynamic range (24 stops). The sensor includes an innovative automatic exposure optimization feature for each of the 736 areas, which improves accuracy for recognizing moving subjects and enables ultra-high DR with better power consumption. Will this sensor be implemented in the Cinema EOS cameras?
Quietly, under the radar, Canon has developed a 1.0-inch back-illuminated stacked CMOS sensor, which achieves an effective pixel count of approximately 12.6 million pixels (4,152 x 3,024) and an industry-leading dynamic range of 148 decibels (dB). ) offers ), which adds up to more than 24 stops! The new sensor uses a new technology that divides the image into 736 areas and automatically determines the best exposure settings for each area. This eliminates the need to synthesize images, often required when performing high dynamic range (HDR) photography in environments with significant differences in brightness, reducing the amount of data processed and improving the recognition accuracy of moving subjects. In short: an ultra HDR sensor that consumes less power and is capable of an exceptionally high DR value. This new methodology revolutionizes recording technology that can also be implemented on advanced video cameras.
The new sensor achieves a dynamic range of 148 dB – the highest performance in the industry among image sensors for monitoring applications (dynamic range at 30 fps is 148 dB. Dynamic range at approx. 60 fps is ‘only’ 142 dB), and it is capable of capturing images at light levels ranging from approximately 0.1 lux to approximately 2,700,000 lux. Decibels, like f-stops, are a logarithmic system, so 6.02 dB is equal to double the signal level. So, to convert the dynamic range from f-stops to decibels (dB), multiply the dynamic range in f-stops by 6.02 (20 log10). For example, the 17-stop of the ALEXA 35 corresponds to the dynamic range of 102.34 dB (17×6.02). That is considered a very high value. Now take for comparison the 148dB quoted by Canon in relation to its new sensor and you get a pretty insane value of dynamic range, which equates to 24.6 stops (148/6.02)! That’s more than the human eye. Astonishing!
The 17-stop of the ALEXA 35 corresponds to the dynamic range of 102.34 dB (17×6.02). That is considered a very high value. Now take for comparison the 148dB quoted by Canon in relation to its new sensor and you get a pretty insane value of dynamic range, which equates to 24.6 stops (148/6.02)!
Canon describes this new technology as follows: “To produce a natural-looking image when capturing images in environments with both bright and dark areas, capturing conventional images with a high dynamic range requires taking several separate images under different lighting conditions and then synthesize them into one image. Because exposure times vary in length, this synthesis operation often results in a problem called “motion artifacts,” where images of moving subjects are merged together but not completely overlapped, resulting in a final image that is blurry. Canon’s new sensor divides the image into 736 different areas, each of which can be automatically set to the optimal exposure time based on the brightness level.This prevents the occurrence of motion artifacts and enables face detection with greater accuracy, even at scanning moving subjects”.
Canon’s new sensor divides the image into 736 different areas, each of which can be automatically set to the optimal exposure based on the brightness level.
As explained, to produce a natural-looking image with conventional sensors when capturing images in environments with both bright and dark areas, capturing high dynamic range images requires taking multiple separate images under different lighting conditions and then stitching them together into a single image (The diagram above uses four exposure types per frame). However, Canon’s new sensor automatically specifies optimal exposure conditions for each of the 736 areas, eliminating the need for image synthesis. Explore the diagram above that demonstrates this methodology.
The methodology behind exposure by area
A portion in which the subject moves is detected based on discrepancies between the first frame (one frame earlier) and the second frame (two frames earlier) to generate a motion map. In the first frame (one frame earlier), the brightness of the subject is recognized for each area and a luminance map is generated. After ensuring that the difference in brightness levels between adjacent areas is not exaggerated (Reducing Side-by-Side Exposure Difference), the exposure conditions are corrected based on information from the motion map and the final exposure conditions are specified. Final lighting conditions are applied to images for corresponding frames.
Canon’s new sensor with the layered HDR functionality can be defined as a disruption in the image sensor market. Dividing a sensor into hundreds of areas to optimize the sensor’s exposure, with the goal of significantly increasing and improving dynamic range, seems like an innovative approach to image capture. Plus, as a bonus, you get a powerful sensor with lower power consumption, as there’s no need to synthesize exposure levels. Canon says this sensor was developed for industrial use. However, this technology can also be implemented on the EOS cameras. Imagine a Cinema EOS with 24 stops of DR. That would be an impressive piece of camera equipment…