Dynamic Range describes the ratio between the maximum and minimum light intensity that can be measured and represented by the camera.
When we talk about dynamic range for cameras, we need to start with the pixel well. When light falls on the pixel, we get electrons that are stored as electrical charge. The capacity of each pixel to hold the charge is the well depth. Once the well is full, the pixel cannot accept any new photos and thereby the pixel is said to be saturated. Dynamic range is the ratio of the maximum light intensity to the minimum light intensity that the sensor can present. Thus, the more the well depth, the more the photons it can accept thereby more the dynamic range. Larger pixel size provides us with higher dynamic range.
This method where we take advantage of the sensor’s inherent Dynamic Range capability is termed as Single Exposure HDR.
Apart from the sensors inherent capability to support higher dynamic range, there is also possibility to have higher dynamic range images by digital processing. This digital processing either happens on the host platform(either PC or embedded system) or can be done on the ISP.
Of course, having it done on the ISP is the most recommended method. Multi-exposure HDR processing is the widely adopted method for capturing wide dynamic range images. This involves combining multiple low dynamic images of the same scene captured with different exposure times into a single HDR image.
We can either go for the inherent sensor based HDR or we can configure the solution with ISP enabling us to have HDR. Based on your use case, experts are Regami Solutions shall be able to guide to the right option that suits your use case.
HDR sensors
Some examples of sensors that can support higher dynamic Range are
1. On Semiconductor – AR0230, AR0233, AR0820
2. Sony – IMX378, IMX390
3. Omnivision - OV2770, OV2775
ISP based Dynamic Range
Some examples of sensors that need ISP to support the HDR capability
1. On Semiconductor - AR0230, AR0233
2. Sony – IMX290, IMX274,
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Sarvesh Rajagopal
