[Spec]: Helper functions for pre and post processing

[amrutha95]

WinML Helper functions Specification document

The HelperFunctions project is a set of APIs that are designed to help developers using WinML with some of the common pre-processing and post-processing tasks.

Image helpers

public static async Task<VideoFrame> ConvertBitmapToVideoFrame(SoftwareBitmap softwareBitmap) Converts Bitmap to VideoFrame, which is accepted as a binding object Arguments: softwareBitmap : The SoftwareBitmap object

public static async Task<TensorFloat> ConvertVideoFrameToTensor(VideoFrame videoFrame, long[] size) Converts VideoFrame to Tensor. Useful in scenarios where Tensor manipulation is required, for example if image needs to be resized, transposed from NCHW to NWHC. Arguments : videoframe : The VideoFrame object to be converted Size : A long[] array containing the sizes of the each dimension of the tensor

public static async Task<SoftwareBitmap> ConvertStorageFileToSoftwareBitmap(StorageFile selectedStorageFile) Converts StorageFile to SoftwareBitmap public static async Task<SoftwareBitmap> ConvertStorageFileToSoftwareBitmap(StorageFile selectedStorageFile) Arguments : selectedStorageFile : The StorageFile object that needs to be converted

public static async Task<SoftwareBitmap> ResizeImage(SoftwareBitmap bitmap, uint height, uint width) Resizes image based on given dimensions public static async Task<SoftwareBitmap> ResizeImage(SoftwareBitmap softwareBitmap, uint height, uint width) Arguments : softwareBitmap: The SoftwareBitmap object that needs to be resized height: Height of the image width: Width of the image

public static async Task<SoftwareBitmap> Crop(SoftwareBitmap softwareBitmap, Rect bounds) Crops images based on bounds provided Arguments : softwareBitmap: The SoftwareBitmap image to be cropped bounds: The bounds of the cropped image

ConvertNCHWToNWHC Transposes an image from NCHW to NWHC. Used depending on what the model is looking for in the input. public static async Task ConvertNCHWToNWHC(SoftwareBitmap softwareBitmap) Arguments: softwareBitmap: The SoftwareBitmap object to be transposed