Added machine learning microservice and object detection (#76)

microservices/src/image-classifier/image-classifier.service.ts

@@ -0,0 +1,48 @@
+import { Injectable, Logger } from '@nestjs/common';
+import * as mobilenet from '@tensorflow-models/mobilenet';
+import * as cocoSsd from '@tensorflow-models/coco-ssd';
+import * as tf from '@tensorflow/tfjs-node';
+import * as fs from 'fs';
+
+@Injectable()
+export class ImageClassifierService {
+  private readonly MOBILENET_VERSION = 2;
+  private readonly MOBILENET_ALPHA = 1.0;
+
+  private mobileNetModel: mobilenet.MobileNet;
+
+  constructor() {
+    Logger.log(
+      `Running Node TensorFlow Version : ${tf.version['tfjs']}`,
+      'ImageClassifier',
+    );
+    mobilenet
+      .load({
+        version: this.MOBILENET_VERSION,
+        alpha: this.MOBILENET_ALPHA,
+      })
+      .then((mobilenetModel) => (this.mobileNetModel = mobilenetModel));
+  }
+
+  async tagImage(thumbnailPath: string) {
+    try {
+      const isExist = fs.existsSync(thumbnailPath);
+      if (isExist) {
+        const tags = [];
+        const image = fs.readFileSync(thumbnailPath);
+        const decodedImage = tf.node.decodeImage(image, 3) as tf.Tensor3D;
+        const predictions = await this.mobileNetModel.classify(decodedImage);
+
+        for (const prediction of predictions) {
+          if (prediction.probability >= 0.1) {
+            tags.push(...prediction.className.split(',').map((e) => e.trim()));
+          }
+        }
+
+        return tags;
+      }
+    } catch (e) {
+      console.log('Error reading file ', e);
+    }
+  }
+}