Нашли:
GCHandle handle = GCHandle.Alloc(dataArray, GCHandleType.Pinned);
IntPtr imageHeaderForBytes = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(MIplImage)));
CvInvoke.cvInitImageHeader(
imageHeaderForBytes,
new Size(160, 120),
Emgu.CV.CvEnum.IPL_DEPTH.IPL_DEPTH_16S, 1, 0, 4);
Marshal.WriteIntPtr(
imageHeaderForBytes,
(int)Marshal.OffsetOf(typeof(MIplImage), "imageData"),
handle.AddrOfPinnedObject());
CvInvoke.cvCopy(imageHeaderForBytes, EMGUImage.Ptr, IntPtr.Zero);
Marshal.FreeHGlobal(imageHeaderForBytes);
handle.Free();