Lens Design and Straylight Analysis for Cameras in Zemax and Speos: Workflow Overview
Designing modern camera systems is increasingly complex. Whether for smartphones, automotive cameras, or industrial vision, optical engineers must deliver high image quality while controlling unwanted effects such as ghost images and stray light.
This article gives a clear, easy-to-follow overview of how Ansys Zemax OpticStudio and Ansys Speos work together to support lens design, straylight analysis, and signal-to-noise evaluation.
Why Use Both Zemax OpticStudio and Speos?
Ansys provides complementary optical simulation tools that address different stages of camera development:
- Zemax OpticStudio is ideal for lens design and optimization, including image quality evaluation and early ghost analysis.
- Ansys Speos is designed for large-scale straylight analysis, realistic environments, and efficient system-level simulation.
Using both tools together enables a smooth, end-to-end workflow for simulation-driven camera design.
Step 1: Lens Design in Zemax OpticStudio
Camera development typically starts in Zemax OpticStudio (Sequential Mode), where engineers define and optimize the lens layout.
General workflow is:
1. Define requirements of the camera system
2. Optimizing optical performance using merit function
3. Ensure robustness of the system through tolerancing analysis
Sequential mode allows fast iteration and is well suited for building a solid optical baseline.
Image Simulation
Zemax image simulation tools help engineers visualize how a real scene appears through the lens. This makes it easier to assess distortion, vignetting, and edge performance – and to communicate results beyond the optics team.
Step 2: Ghost Analysis Before Straylight
Before full straylight analysis, ghost images must be addressed.
In Zemax, ghost analysis helps engineers:
- Identify unwanted reflections between lens surfaces
- Evaluate ghost intensity and location
- Improve performance using coatings and design changes
A simple rule applies: poor ghost performance leads to poor straylight results. Fixing ghosts early saves time later.
Step 3: Straylight Analysis in Zemax (Non-Sequential Mode)
Once the lens design is stable, it is converted to non-sequential mode for straylight analysis.
This enables modeling of:
- Scattering
- Ray splitting
- Complex interactions with mechanical components
Tools like the Sequence Selector help group and filter ray paths, making it easier to understand which surfaces contribute most to straylight.
Step 4: Export to Ansys Speos
For more demanding studies, the optical system can be exported from Zemax to Ansys Speos using Optical Design Exchange (ODX).
Speos is especially useful when:
- Millions of rays where GPU acceleration and HPC can be leveraged
- Multiple illumination or sun positions must be evaluated
- There is a high number of CAD geometry and realistic environments are involved
This is particularly relevant for automotive and outdoor camera systems.
Step 5: Straylight and SNR Evaluation in Speos
In Speos, engineers can perform advanced straylight analysis and signal-to-noise ratio (SNR) evaluation.
Key benefits include:
- Clear separation of useful signal and unwanted light
- Identification of critical straylight paths
- Quantitative energy analysis on the sensor
This insight supports targeted design improvements rather than trial-and-error changes.
Reducing Straylight in Camera Systems
Simulation results typically guide practical mitigation strategies such as:
- Applying anti-reflective (AR) coatings
- Adding or refining baffles and apertures
- Optimizing lens hoods and mechanical geometry
While straylight cannot always be eliminated, simulation helps define acceptable limits and informed design trade-offs.
Conclusion
By combining lens design in Zemax OpticStudio with system-level straylight analysis in Ansys Speos, optical engineers gain a practical and efficient workflow for camera development. This simulation-first approach reduces risk, improves insight, and supports better-performing imaging systems.
Register for our upcoming webinar!
📆 On April 15, we will host a new live webinar on the topic Camera Straylight Simulation in Ansys Speos (Zemax‑to‑Speos Workflow). If this topic is of interest to you, make sure to save your spot now!
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🎥 Coffee with an Expert – Lens Design & Analysis for Cameras with Zemax & Speos
