Different image resolutions affecting similarity

[michelle54725]

Using the same image but one is 800x600 and other is 2316x3088 and getting distance values as high as 0.80! The face is very clear in the image. Any idea why or tips to reduce this effect?

I'm using tfjs-node with monkey patch, SsdMobilenetv1Options, faceLandmark68Net, and faceRecognitionNet.

[vladmandic]

can you post actual detected faces from both images? or even better, upload originals somewhere and i'll test. as it is, i don't have much to go on.

[michelle54725]

Thanks for the quick response! Turns out that tf.node.decodeImage (and decodeJpeg) was rotating some images, so I'm using sharp to rotate all images back. So this is no longer a product issue, but would you happen to know why decoding some images would rotate them? This also happens with sharp().toBuffer().

code I used to test:

  const response = await fetch(url);
  const arrBuf = await response.arrayBuffer();
  const uint8Arr = new Uint8Array(arrBuf);

  // is not rotated
  writeFile(`./test_${which}_og.jpeg`, uint8Arr, (err) => {
    if (err) console.log(err);
  }); 

  // is rotated
  const test1 = await sharp(uint8Arr).toBuffer();
  writeFile(`./test_${which}_test1.jpeg`, test1, (err) => {
    if (err) console.log(err);
  });

  // is rotated
  const test2 = tf.node.decodeJpeg(uint8Arr);
  console.log(test2.shape); // confirm already rotated before encoding it back
  const encodedTensor = await tf.node.encodeJpeg(test2);
  const dataBuf = Buffer.from(encodedTensor);
  writeFile(`./test_${which}_test2.jpeg`, dataBuf, (err) => {
    if (err) console.log(err);
  });

[vladmandic]

most likely images contain exif tag orientation closing the issue as resolved, but feel free to post further on this thread with any questions.