public class HomeController : Controller
{
  ...
    public string getDataURL()
    {
        string dataURL = "data:image/png;base64,iVBORw0KGgo...
        return (dataURL);
    }
    ...
}

View:
$.get('/Home/getDataURL', null, function (d) {
    var dataURL=d;
    var img = new Image();
    img.onload = function () {
        ctx.drawImage(img, 150, 0);
    }
    img.src = dataURL;
});