var api = OcrApi.Create();
api.Init(Languages.English);
​using (var renderer = OcrPdfRenderer.Create(@"d:\0\output_pdf_file", @"tessdata"))
{
	renderer.BeginDocument("document title");
	foreach (Stream stream in streamCollection)
	{
		var bmp = Bitmap.FromStream(stream) as Bitmap;
		using (var pix = OcrPix.FromBitmap(bmp))
		{
			api.ProcessPage(pix, null, 0, renderer);
		}
	}
	renderer.EndDocument();
}