Sony IMX900 vs. IMX676 - Understanding HDR Technologies
High Dynamic Range (HDR) is an important feature for industrial cameras operating in scenes with significant differences between bright and dark areas.
However, not all HDR technologies work in the same way.
Sony's IMX900 and IMX676 image sensors demonstrate two different approaches to extending dynamic range.
In this FAQ, we answer the most common questions about Sony IMX900 Quad HDR, Sony IMX676 DOL-HDR, and Clear HDR, and explain what these differences mean for industrial imaging applications.
What is HDR in an industrial camera?
HDR, or High Dynamic Range, enables a camera to capture image information across a wider range of brightness levels. This helps preserve details in both bright and dark areas of a scene, for example when inspecting reflective surfaces, reading barcodes under uneven illumination, or imaging objects with strong contrasts.
However, HDR performance depends not only on the advertised dynamic-range value, but also on the sensor technology, exposure method, image processing and application requirements.
Is the HDR of the Sony IMX900 and IMX676 the same?
No. Although both sensors support HDR, they use different HDR technologies.
The Sony IMX900 uses Quad HDR, which assigns different exposure times to the four pixels in each 2×2 pixel group.
The Sony IMX676 supports Digital Overlap HDR (DOL-HDR) and Clear HDR, which use different approaches to capturing and processing high-contrast scenes.
As a result, the two sensors should not be considered equivalent simply because both offer HDR functionality.
How does Sony IMX900 Quad HDR work?
Sony IMX900 Quad HDR uses a spatial multi-exposure approach. The four pixels in a 2×2 group can be assigned different exposure times, allowing the sensor to capture information from different brightness levels simultaneously.
The resulting data can then be combined downstream to create an HDR image. This approach is particularly interesting for industrial vision applications where global shutter operation, motion handling and high dynamic range are important.
How does Sony IMX676 DOL-HDR work?
Sony IMX676 Digital Overlap HDR uses multiple exposure conditions to extend the dynamic range. The resulting image data is combined to produce an HDR image.
As with other multi-exposure HDR approaches, movement between exposures can potentially lead to motion artifacts. This makes the specific HDR implementation and application conditions important when evaluating the sensor.
What is Clear HDR, and how does it differ from DOL-HDR?
Clear HDR is another HDR technology available on the Sony IMX676. Unlike conventional multi-exposure approaches, Clear HDR uses a common exposure time for the scene and compensates for differences in brightness through different gain levels.
This can help address certain motion-related limitations of sequential exposure methods. However, because darker areas may require higher gain, Clear HDR can potentially result in increased image noise, particularly in low-light or high-contrast scenes.
Which HDR technology is better for industrial vision?
There is no universal answer.
The appropriate HDR technology depends on the application.
For example, global shutter operation and Quad HDR can be particularly relevant for industrial applications involving moving objects, while DOL-HDR and Clear HDR offer different approaches to handling high-contrast scenes.
When selecting a camera, it is therefore important to consider not only the HDR specification, but also motion, exposure control, noise, image processing and the actual imaging requirements.
Does a higher HDR value always mean better image quality?
No. A higher advertised dynamic-range value does not automatically mean better results in every application.
The practical image quality depends on factors such as illumination, exposure settings, gain, noise, motion, image processing and the way HDR data is reconstructed. Comparing the underlying HDR technologies is therefore essential when selecting an industrial camera.
Where can I learn more about Sony IMX900 and IMX676 HDR?
Our white paper provides a more detailed comparison of the HDR technologies used by the Sony IMX900 and Sony IMX676, including their operating principles, differences, advantages and potential limitations.
Download the white paper: WhitePaper_HDR Beyond The Numbers_IMX900_vs_IMX676enUS.pdf
Explore the technical details behind Quad HDR, DOL-HDR and Clear HDR, and learn what these differences mean for industrial imaging applications.