Humans have always had a keen interest in innovating to make their lives easier. This is illustrated constantly throughout history, but most recently is shown by the demand for IoT and robotics technologies. The key to making these two things a bigger part of everyday life? The ability to see, so they could more easily interact with their world. This article from onsemi and Arrow explores how the PRISM reference design can help accelerate cutting-edge imaging and vision projects.
Integrating image sensors into products brings transformative capabilities. This enhances human perception by detecting unseen details, navigating inaccessible areas, enabling continuous monitoring, and facilitating real-time robotic interactions. While selecting the right image sensor is essential, other factors — such as the choice of a host processor — also significantly impact development timelines and time to market.
Efficient design with off-the-shelf components
Utilizing off-the-shelf parts for early-stage evaluation, testing, and prototyping can expedite the design process. However, differences between prototype components and final production hardware often require additional software adjustments, which may extend development time. For instance, although many teams use Raspberry Pi for prototyping due to its availability and affordability, it’s not always scalable for mass production. Instead, development boards featuring Systems on Modules (SoMs) from 96Boards or processor manufacturers can offer greater scalability — allowing direct software integration into production designs. However, these choices may be constrained by the availability of compatible image sensors and camera connectors on the carrier board.
Streamlining camera connections
MIPI CSI-2 is the predominant interface for connecting image sensors to processors. However, the absence of a standard connector or pinout across processor suppliers complicates integration. Companies like NXP and Nvidia are shifting toward a 22-pin ribbon connector and pinout popularized by the Raspberry Pi Zero; it supports a four-channel MIPI bus and simplifies the connection of cameras to evaluation boards. Until a universal standard emerges, adapter boards serve as practical solutions to bridge differences between camera and processor configurations.
Standardized camera interfaces
For serialized camera data, common interfaces like USB, GigE, CoaxExpress, and Camera Link are prevalent. Although these utilize MIPI interfaces internally, many include their own host processors to facilitate seamless integration with diverse systems.
PRISM reference design by onsemi
onsemi has pioneered a standardized interface through their Imaging Access System (IAS) and now extends this with the PRISM reference design; it provides a unified connector and pinout. Such a setup allows multiple camera modules to interface with the Demo3 evaluation system or various host processor systems through compatible adapter boards. Alif Semiconductor’s evaluation boards, for example, directly incorporate this connector for straightforward integration.
Figure 1: onsemi Demo3 with camera module.
Arrow’s supplier network for every development phase
With Arrow’s extensive supplier base, developers gain access to essential tools at every phase of imaging product development:
- Proof-of-concept: Arrow suppliers like TechNexion and Basler provide complete cameras with USB or GMSL interfaces for image capture — facilitating early validation of imaging algorithms.
- Sensor evaluation: onsemi’s Demo3 EVK platform and DevWare software enable in-depth sensor evaluation — allowing engineers to optimize sensor settings for peak performance.
- Software development: With adapter boards and Linux drivers, engineers can integrate the same sensors with development platforms from Nvidia, NXP, or Lattice to expedite software development.
- Mass production: Suppliers such as Appleye and Leopard Imaging offer custom camera solutions designed for production — aligning with mass-market requirements.
Case study example 1: Doorbell camera project
Figure 2: NXP Thor96 with camera and adapter
A customer aims to develop a battery-operated 4K doorbell camera with low power consumption and accelerated time to market. The onsemi AR0830 image sensor, part of the Hyperlux LP (Low Power) family, is an ideal fit due to its low power requirements and motion-triggered wake feature. It utilizes an Appleye camera module (AE-CCM-AR0830-C-68) connected through an onsemi AP1302 ISP to an NXP i.MX8M processor. This way, the development team can start application software while refining the hardware design using the 96Boards Thor96 development board and the Shiratech SRT-VISION96-AR0830 mezzanine. The available Linux driver with ISP tuning settings minimizes development time, which saves months of work.
Case study example 2: Live stage performance capture system
Figure 3: TechNexion AR0822 options
Another customer is retrofitting a system with multiple cameras to capture live stage performances in 4K resolution with a USB interface. Given the unpredictable lighting conditions — including pyrotechnics — a wide dynamic range is crucial. TechNexion’s pre-existing module, featuring the onsemi AR0822 sensor, offers excellent low-light performance and dynamic range up to 120dB in HDR mode. The camera's modular design supports various lens options, such as a C-mount, and comes equipped with a pre-tuned ISP and compatible software. This makes it an ideal choice for such a demanding project.
