#StackBounty: #android #tensorflow #xamarin #xamarin.android TensorFlow object detection fails on Xamarin Android with a reshape issue

Bounty: 50

I am following this blog post and GitHub almost exactly:



But when I run, take a picture and call this line:

var outputs = new float[tfLabels.Count];
tfInterface.Feed("Placeholder", floatValues, 1, 227, 227, 3);
tfInterface.Run(new[] { "loss" });
tfInterface.Fetch("loss", outputs);

The app actually crashes and generates the error below on the .Run line.

I get this error in the output window (and the app crashes):

04-04 17:39:12.575 E/TensorFlowInferenceInterface( 8017): Failed to
run TensorFlow inference with inputs:[Placeholder], outputs:[loss]
Unhandled Exception:

Java.Lang.IllegalArgumentException: Input to reshape is a tensor with
97556 values, but the requested shape requires a multiple of 90944
[[Node: block0_0_reshape0 = Reshape[T=DT_FLOAT, Tshape=DT_INT32,

According to the posts I am reading from the searching I am doing on this error, I sort of understand this is due to the image not fitting the expected size exactly but in the example I am following, this is resized to fit 227×227 everytime and converted to float like in these lines:

var resizedBitmap = Bitmap.CreateScaledBitmap(bitmap, 227, 227, false).Copy(Bitmap.Config.Argb8888, false);

var floatValues = new float[227 * 227 * 3];
var intValues = new int[227 * 227];

resizedBitmap.GetPixels(intValues, 0, 227, 0, 0, 227, 227);

for(int i = 0; i < intValues.Length; i++)
     var val = intValues[i];
     floatValues[i * 3 + 0] = ((val & 0xFF) - 104);
     floatValues[i * 3 + 1] = (((val >> 8) & 0xFF) - 117);
     floatValues[i * 3 + 2] = (((val >> 16) & 0xFF) - 123);

So, I don’t understand what is causing this or how to fix it. Please help!

UPDATE: I found out the issue is with my model or my labels. I found this out by simply swapping in the model and label file from the sample/github above while leaving all my code the same. When I did this, I no longer get the error. HOWEVER, this still doesn’t tell me much. The error is not very explanatory to point me in a direction of what could be wrong with my model. I assume it is the model because the labels file is simply just a text file with labels on each line. I used Custom Vision Service on Azure to create my model. It trained fine and tests just fine on the web portal. I then exported it as TensorFlow. So, I am not sure what I could have done wrong or how to fix it.


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