Embedded System Development for Imaging System

By: Jim Herrmann – Founder & Principal Engineer

Client: Medical Imaging Device Manufacturer

Capabilities Demonstrated

Embedded hardware development
Embedded software/firmware development
FPGA development
Mixed-signal circuit board design and PCB layout
Real-time video image pipeline processing
Motion control
Windows kernel device driver and application software
Phase 0 – System Architecture and Requirements Capture

The Challenge

The client had identified several “show-stopper” issues (including various image artifacts and other reliability concerns) with their “production intent” design.

At that time-critical juncture, they asked Re:Build AppliedLogix to jump in and critically assess the system design end-to-end, generate a findings and recommendations summary, and then proceed to modify and enhance the design as needed to make it truly production-ready.

When developing a product, it’s super important that everyone works closely together, as a unified team, regardless of whether that team is spread across multiple companies or all in-house. In this case, it was even more important because we were dealing with the regulated world of medical devices, where the development processes are often more rigorous. From the start, the Re:Build AppliedLogix team integrated its efforts within and under the client’s ISO quality process. Thereby avoiding any new speedbumps within their FDA 510(K) approval process.

The Re:Build AppliedLogix team needed to:

quickly and comprehensively evaluate the failure modes,
brainstorm and nail-down the root causes,
and then develop a targeted set of design updates to make it production-ready.

Re:Build AppliedLogix assembled a multi-functional team, deployed onto the customer’s site, and then built-out a “war-room” of sorts to maximize the daily flow of information and accelerate the entire process. The team operated across multiple engineering domains in-parallel: hardware, software, FPGA, and firmware. A lot of pieces needed to come together quickly and all play nicely together.

Solution

The Re:Build AppliedLogix team completed, what is best described as a complete revamping of the embedded hardware and software, in 3 phases:

Detailed assessment/analysis coupled with system design modifications recommendations
Design execution of the full set of “production intent” HW and SW updates
Rigorous performance testing followed by “final production” design updates

Benefits

A combined team effort between the client and Re:Build AppliedLogix led to a final production design that met all of its operational and performance targets, enabling a successful product launch (this was the client’s first revenue-bearing product, so successful product launch was all the more critical).

System Overview

The initial launch device, targeted at clinicians, offered a “desk-side” confocal laser microscope platform, loosely tethered to a host PC/Windows platform. This revolutionary system delivered non-invasive, real-time imaging of human skin tissue at the cellular level. These unique capabilities enabled scientists and physicians to characterize cellular structures that are otherwise invisible to the naked eye.

The key functional design elements for the embedded controller subsystem included:

Motion control loops and related processing for:
- Galvanometer-based slow scan direction beam deflection
- Polygon-based fast scan direction beam deflection
- Z-axis servo motor control to establish and maintain the desired focal plane
Photomultiplier tube (PMT) based imager
Target illumination selectable via 1 of 3 DAC channels driving unique wavelength S-type laser diodes
Raster image synchronization and capture
Image serialization and transmission to the host system

In addition to the embedded controller subsystem, a custom PCIe-based host interface card and associated device driver software were also designed. This card (10-layer, controlled impedance) was FPGA-based with local DDR3 memory for the image path buffering and control.

Software Developed

Image/data acquisition
Image acquisition state machine
PID loop for auto image control
Supervisory state machine
System calibration routines
End-of-line custom functional test
Windows kernel device driver
Application Programming Interface library

Hardware Developed

FPGA + ARM microcontroller working in tandem
Mixed-signal, 10-layer, controlled impedance PCB
Precision analog – multiple ADCs / DACs
Integrated motor controllers
Proprietary high-speed serial image transfer link

Ready to Get Started?

Let’s talk about your unique challenges and how Re:Build AppliedLogix can help you.