After roughly an hour the telemetry stopped and the Azure Percept displayed a message which wasn’t terribly helpful.
I had manually created the Azure IoT Hub and selected the “Free Tier” (I was trying to keep my monthly billing reasonable) then as I was stepping through the Azure Percept setup wizard I didn’t read the warning message highlighted below.
The Azure Percept generates a lot of messages and I had quickly hit the 8000 messages per day limit of the “Free Tier”.
I had to create a new Azure IoT Hub, repave the Azure Percept Device (there were some updates and I had made some mistakes in the initial setup) and reconfigure the device.
I work on a SmartAg computer vision based application that uses security cameras to monitor the flow of cattle through stockyards. It has to control some local hardware, display real-time dashboards, and integrate with an existing application so a “zero code” solution wouldn’t work.
The initial plan was to take the Azure Percept to a piggery to see if I could build a Proof of Concept(PoC) of a product that the CEO and I had been discussing for a couple of weeks.
But shortly after I started working on this series of blog posts New Zealand went into strict lockdown. Only essential shops like supermarkets and petrol stations were open, our groceries were being delivered, and schools were closed.
I needed a demonstration application which used props I could source from home and the local petrol station. In addition my teenage son’s school was closed so he could be the project “intern”.
While at the local petrol station to buy milk I observed that they had a large selection of confectionary so we decided to build a series of object detection models to count different types of chocolates.
In a retail scenario this could be counting products on shelves, pallets in a cold store, or at the SmartAg start-up I work for counting cattle in a yard.
Configuring The Test Environment
I have not included screen shots of the hardware configuration process as this has been covered by other bloggers. Though, for projects like this I always create a new resource group so I can easily delete all the resources so my Azure invoice doesn’t cause “bill shock”.
I also created the Azure IoT Hub before configuring the Percept device rather than via the Device provisioning process.
The intern trialed different trays, camera orientations, and lighting as part of building a test rig on the living room floor. After some trial and error, he identified the optimal camera orientation (on top of the packing foam) and lighting (indirect sunlight with no shadows) for reliable inferencing. As this was a proof-of-concept project we limited the number of variables so we didn’t have to collect lots of images which the intern would then have to mark up.
Azure Percept Studio + CustomVision.AI for capturing and marking up images
The intern then spent an afternoon drawing minimum bounding rectangles (MBRs) around the different chocolates in the images he had collected.
The intern then decided to focus on the chocolate bars after realising they were much easier and faster to markup than the M&Ms.
The intern repeatedly trained the model adding additional images and adjusting parameters until the results were “good enough”.
Fine-tuning the Configuration
After using the test rig one evening we found the performance of the model wasn’t great, so the intern collected more images with different lighting, shadows, chocolate bar placements, and orientations to improve the accuracy of the inferencing.
Inspecting the Inferencing Results
After several iterations the accuracy of the chocolate bar object detection model was acceptable I wanted to examine the telemetry that was being streamed to my Azure IoT Hub.
In Azure Percept Studio I could view (in a limited way) inferencing telemetry and check the quality and format of the results.
I use Azure IoT Explorer on other projects to configure devices, view telemetry from devices, send messages to devices, view and modify device twinJSON etc. So I used it to inspect the inferencing results streamed to the Azure IoT Hub.
In an afternoon the intern had configured and trained a Custom Vision project for me that I could use to to build some “low code” integrations .
If the image capture delay is too short there will be images with hands.
Though, the untrained model did identify the hands
The intern also discovered that by including images with “not favourites” the robustness of the model improved.
When I had to collect some more images for a blog post, I found the intern had consumed quite a few of the “props” and left the wrappers in the bottom of the Azure Percept packaging.