private void ApplyFilter()
        {
            int orignalPage = _cell.Image.Page;

            _cell.Image.Page = _cell.ActiveSubCell + 1;
            _region          = _cell.Image.GetRegion(null);
            _cell.RemoveRegion();
            HistogramEqualizeType type = HistogramEqualizeType.None;

            switch (_cbColorSpace.SelectedIndex)
            {
            case 0:
                type = HistogramEqualizeType.Rgb;
                break;

            case 1:
                type = HistogramEqualizeType.Yuv;
                break;

            case 2:
                type = HistogramEqualizeType.Gray;
                break;
            }

            HistogramEqualizeCommand command = new HistogramEqualizeCommand(type);

            _mainForm.FilterRunCommand(command, false, true);


            _cell.Image.SetRegion(null, _region, RasterRegionCombineMode.Set);
            if (_cell.Image.BitsPerPixel == 8)
            {
                _cell.SetWindowLevel(_cell.ActiveSubCell, 255, 128);
            }
            else if (_cell.Image.BitsPerPixel == 16)
            {
                _cell.SetWindowLevel(_cell.ActiveSubCell, 65000, 32000);
            }

            _cell.Image.Page = orignalPage;
            _cell.Invalidate();
        }