**6. Further discussion on potential and limitation**

The use of Microsoft Excel for implementing biomedical image processing and analysis methods as demonstrated in the preceding sections is a straightway possibility. This possibility is mainly because each blank worksheet acts as a fresh canvas where the cells are available for performing pixel by pixel computations or can be colored up to 16,777,216 colors based on RGB input data. Excel computations are also generally straightforward with some familiarity with entering formulas making use of common mathematical functions. Therefore, with the data available in Excel, already existing features and tools can be used to perform manipulations on the data. Further, as a general use spreadsheet program, Excel has a well-respected performance with data handling and now presents 2D and 3D graphing capabilities that are comparable to other image processing applications. Specifically, 3D surface and contour charts are two effective ways of visualizing the two-dimensional image data in Excel. These charts can be copied into other Microsoft Office Suite applications where they can further be directly formatted. This means that the final chart format does not need to be achieved in the Excel file. As an embedded chart in Word or PowerPoint, for instance, they can be shared between users and finalized later without requiring the original Excel file.

Although Excel does not currently have its own automated means of importing image data directly from an image file, the data can be copied from other resources such as [12]. However, a more efficient means of acquiring the image data from multiple files all at the same time is by using the RGB2X 1.0 software application [24]. RGB2X offers the advantages of multiple image file handling and creation of Excel files saved in the same location and having the same base name(s) as the original image file(s). Also, an additional worksheet in the Excel files having unidimensional forms of the R, G, and B data makes four data worksheets which can be used for performing certain analysis like histogram and clustering.

As a limitation, the RGB2X software application by design scales down images larger than 255 × 255 pixels during the data extraction process. This is to allow for viewing the data as charts in Excel. However, the reduced resolution may influence the quality of the raw and processed data. Also, solely using Excel's standard features for image processing and analysis can retard the processing speed in high throughput applications. Furthermore, re-exporting RGB-type images of output data as standard image files is limited compared to advanced professional image processing software. Nevertheless, the limitations of Excel's standard features and tools and that of re-exporting RGB-type images can be eliminated by including some VBA programming in Excel as depicted with image data fusion macro in the Appendix.
