Getting Started with DeGirumJS
Welcome to the DeGirumJS: a JavaScript AI Inference SDK! This guide will help you get started with integrating AI inference capabilities into your web application. Follow the steps below to set up your environment, connect to an AI server or the cloud, and run inference.
Table of Contents
- Getting Started with DeGirumJS
- Table of Contents
- Introduction
- Setup
- Basic Usage
- Model Options
- API Reference
Introduction
The JavaScript AI Inference SDK allows you to connect to AI Server or Cloud Zoo instances, load AI models, and perform inference on various data types. This guide provides a step-by-step tutorial on how to use the SDK effectively.
Setup
Import the SDK
To start using the SDK, include the following script tag in your HTML file:
Basic Usage
DeGirumJS allows you to load models from an AI server or Cloud Zoo and perform inference on the AI Server hardware or in the cloud. For AI server inference (local or LAN server), you need to have an AI Server running with http protocol enabled :
See AI Server documentationFor running cloud inference or to be able to load a model from the cloud, you need to specify your cloud token.
Where do I get my cloud token?
Connect to an AI Server
Instantiate the dg_sdk
class and connect to the AI server using the connect
method:
let dg = new dg_sdk();
const AISERVER_IP = 'ws://localhost:8779';
let zoo = dg.connect(AISERVER_IP);
let dg = new dg_sdk();
const AISERVER_IP = 'ws://localhost:8779';
const ZOO_URL = 'https://cs.degirum.com/degirum/public';
const secretToken = prompt('Enter secret token:');
let zoo = dg.connect(AISERVER_IP, ZOO_URL, secretToken);
Connect to the Cloud
For running Cloud inference, specify 'cloud' as the first argument, and include the URL of the cloud zoo and your token:
let dg = new dg_sdk();
const ZOO_URL = 'https://cs.degirum.com/degirum/public';
const secretToken = prompt('Enter secret token:');
let zoo = dg.connect('cloud', ZOO_URL, secretToken);
Load a Model
Now, you can load a model using the zoo class instance's loadModel
method:
const MODEL_NAME = 'yolo_v5s_face_det--512x512_quant_n2x_cpu_1';
const modelOptions = {
overlayShowProbabilities: true
// Any other custom options for your Model (see Model Options section below)
};
let model = await zoo.loadModel(MODEL_NAME, modelOptions);
Perform Inference
Use the predict
method to perform inference on an input image:
const image = ''; // Some image. Can be Blob, File, base64string, HTMLImageElement, HTMLVideoElement, HTMLCanvasElement, ArrayBuffer, TypedArray, ImageBitmap, URL to an image
const result = await model.predict(image);
console.log('Result:', result);
Displaying Results
You can display prediction results to a HTMLCanvasElement
:
// Assuming your Canvas Element has the id 'outputCanvas'
let canvas = document.getElementById('outputCanvas');
model.displayResultToCanvas(result, canvas);
Understanding the Result Object Structure
The result
object contains the predictions made by the model, such as detected objects, classes, probabilities, bounding boxes, and more. For a detailed breakdown of the structure and properties of the result object, please refer to the Result Object Structure documentation.
Simple Example HTML Page
To get started with a simple example page, we need the following HTML elements on the page:
The script tag to import DeGirumJS
A canvas element to display inference results.
An input element to browse and upload images.
Here is a HTML page that will perform inference on uploaded images and display the results:
<script src="https://docs.degirum.com/degirumjs/0.1.0/degirum-js.min.obf.js"></script>
<canvas id="outputCanvas" width="400" height="400"></canvas>
<input type="file" id="imageInput" accept="image/*">
<script type="module">
// Grab the outputCanvas and imageInput elements by ID:
const canvas = document.getElementById('outputCanvas');
const input = document.getElementById('imageInput');
// Initialize the SDK
let dg = new dg_sdk();
// Query the user for the cloud token:
const secretToken = prompt('Enter secret token:');
// Inference settings
const MODEL_NAME = 'yolo_v5s_face_det--512x512_quant_n2x_cpu_1';
const ZOO_URL = 'https://cs.degirum.com/degirum/public';
const AISERVER_IP = 'ws://localhost:8779';
// Connect to the cloud zoo
let zoo = dg.connect(AISERVER_IP, ZOO_URL, secretToken);
// Model options
const modelOptions = {
overlayShowProbabilities: true
};
// Load the model with the options
let model = await zoo.loadModel(MODEL_NAME, modelOptions);
// Function to run inference on uploaded files
input.onchange = async function () {
let file = input.files[0];
// Predict
let result = await model.predict(file);
console.log('Result from file:', result);
// Display result to canvas
model.displayResultToCanvas(result, canvas);
}
</script>
Model Options
When loading a model, you can specify various options to customize its behavior:
inputCropPercentage
: Set the percentage to crop the input image forcrop-first
andcrop-last
padding methods.inputLetterboxFillColor
: Set the color for letterbox background.inputPadMethod
: Set the padding method for input. Options:letterbox
(default),stretch
,crop-first
,crop-last
.labelBlacklist
: Specify labels to exclude.labelWhitelist
: Specify labels to include.outputConfidenceThreshold
: Set the confidence threshold for outputs.outputMaxClassesPerDetection
: Set the maximum number of classes per detection.outputMaxDetections
: Set the maximum number of detections.outputMaxDetectionsPerClass
: Set the maximum number of detections per class.outputNmsThreshold
: Set the non-maximum suppression threshold.outputPoseThreshold
: Set the pose threshold.outputPostprocessType
: Set the post-process type.outputTopK
: Set the top K results to output.outputUseRegularNms
: Use regular non-maximum suppression.overlayAlpha
: Set the transparency of the overlay.overlayColor
: Set the color for overlay. Can be one RGB color or an array of RGB colors.overlayFontScale
: Set the font scale for overlay text.overlayLineWidth
: Set the width of the overlay lines.overlayShowLabels
: Show or hide labels in the overlay.overlayShowProbabilities
: Show or hide probabilities in the overlay.saveModelImage
: Flag to enable attaching the model input image to the results.autoScaleDrawing
: Flag to enable auto-scaling of the drawn text/boxes to the original image size. Default off!deviceType
: Specify the runtime and hardware for inference. See Device Management for Inference.measureTime
: Flag to enable collection of max, min, count, and average of time taken for inference duration and preprocessing duration in milliseconds. Off by default.
To destroy / clean up a model instance, use the cleanup
method:
Device Management for Inference
Both AIServerModel
and CloudServerModel
classes offer flexible ways to manage device types, allowing you to configure and switch between devices dynamically.
Supported Device Types
Each model has a set of SupportedDeviceTypes
, which indicates the runtime/device combinations that are compatible for inference. The format for device types is "RUNTIME/DEVICE"
, where:
- RUNTIME refers to the AI engine or runtime used for inference (e.g., TENSORRT
, OPENVINO
).
- DEVICE refers to the hardware type (e.g., CPU
, GPU
, NPU
).
AIServerModel / CloudServerModel Device Management
In the AIServerModel
and CloudServerModel
classes, device management is integrated into both the initialization and runtime phases of the model lifecycle. Below are key scenarios and examples:
-
Default Device Type Selection: When you load a model without specifying a device type, the default device type specified in the model parameters is selected.
2. Switching Device Types After Initialization: You can change the device type even after the model has been initialized. The model will validate the requested device type against the system’s supported device types.let model = await zoo.loadModel('your_model_name'); console.log(model.deviceType); // Outputs: "DefaultRuntime/DefaultAgent"
If the requested device type is not valid, an error will be thrown. 3. Specifying a Device Type During Initialization: You can specify a device type when loading the model. The model will start with the specified device type if it’s available.
4. Handling Multiple Device Types: The SDK allows you to provide a list of device types. The first available option in the list will be selected.let model = await zoo.loadModel('your_model_name', { deviceType: 'RUNTIME2/CPU' }); console.log(model.deviceType); // Outputs: "RUNTIME2/CPU"
5. Fallback and Error Handling: If none of the specified device types are supported, the model will throw an error, ensuring that only valid configurations are used.model.deviceType = ['RUNTIME3/CPU', 'RUNTIME1/CPU']; console.log(model.deviceType); // Outputs: "RUNTIME3/CPU" if available, otherwise "RUNTIME1/CPU"
6. Supported Device Types: You can check the supported device types for a model using thetry { model.deviceType = ['INVALID/DEVICE', 'ANOTHER_INVALID/DEVICE']; } catch (e) { console.error('Error: Invalid device type selection'); }
supportedDeviceTypes
property. 7. System Supported Device Types You can check the system’s list of supported devices for inference using thegetSupportedDevices()
method of thedg_sdk
class.Device management in bothlet dg = new dg_sdk(); let aiserverDevices = dg.getSupportedDevices('targetAIServerIp'); console.log(supportedDevices); // Outputs: ["RUNTIME1/CPU", "RUNTIME2/CPU", "RUNTIME3/CPU"] let cloudDevices = dg.getSupportedDevices('cloud'); console.log(supportedDevices); // Outputs: ["RUNTIME1/CPU", "RUNTIME2/CPU", "RUNTIME3/CPU"]
AIServerModel
andCloudServerModel
is designed to be flexible, allowing you to fine-tune the inference environment. You can easily switch between device types, handle fallbacks, and ensure that your models are always running on supported configurations.
Measure Time Usage
Enabling the measureTime
flag will create a timeStats
object within the model which holds various statistics (max, min, count, average) to track how long certain operations took.
Operations Tracked
ImagePreprocessDuration_ms
: Time taken for preprocessing the input image.CorePreprocessDuration_ms
: Duration of server-side pre-processing step.CoreInferenceDuration_ms
: Time taken for the actual inference operation on the server (between sending frame and receiving results).CoreLoadResultDuration_ms
: Duration of server-side data movement step.CorePostprocessDuration_ms
: Duration of server-side post-processing step.PythonPreprocessDuration_ms
: Duration of client-side pre-processing step including data loading and data conversion time.FrameTotalDuration_ms
: Total duration from calling thepredict()
orpredict_batch()
method to receiving the results.DeviceInferenceDuration_ms
: (Orca models only) Duration of AI inference computations on AI accelerator hardware (DeGirum Orca).DeviceTemperature_C
: (Orca models only) Internal temperature of AI accelerator hardware in Celsius (DeGirum Orca).DeviceFrequency_MHz
: (Orca models only) Working frequency of AI accelerator hardware in MHz (DeGirum Orca).
Available methods
getTimeStats()
: Use this method to return a formatted string of all the statistics collected so far.resetTimeStats()
: Use this method to delete all your old statistics and create a freshtimeStats
object to collect more statistics with.- To access the
timeStats
object directly, you can usemodelName.timeStats.stats["statName"]
, where thestatName
is one of the operations tracked.
Example usage
let model = await zoo.loadModel('your_model_name', { measureTime: true });
let result = await model.predict(image);
console.log(model.getTimeStats()); // Pretty print time stats
// Access client-side and server-side timing stats
let preprocessDuration = model.timeStats.stats["ImagePreprocessDuration_ms"]; // Get image preprocess duration (min, avg, max, count)
let preprocessMin = model.timeStats.stats["ImagePreprocessDuration_ms"].min; // Get min image preprocess duration
let inferenceDuration = model.timeStats.stats["CoreInferenceDuration_ms"]; // Get core inference duration (min, avg, max, count)
let inferenceMax = model.timeStats.stats["CoreInferenceDuration_ms"].max; // Get max core inference duration
let frameTotalDuration = model.timeStats.stats["FrameTotalDuration_ms"]; // Get total time taken for the entire frame processing
let deviceTemp = model.timeStats.stats["DeviceTemperature_C"]; // Get device temperature if available
model.resetTimeStats(); // Reset time stats
API Reference
For detailed information on the SDK's classes, methods, and properties, refer to the API Reference.