Activity 1: Digital Scanning

In this activity, a digitally scanned hand-drawn plot was obtained from an old journal in the CS Library, titled “Physical Review Jul-Dec 1922”.

Figure 1. Scanned graph from "Physical Review Jul-Dec 1922"

The pixel locations of the points in the plot were determined using GIMP application and tabulated in the Excel. The pixel location of the graph‘s origin was also determined and then subtracted to each of the predetermined pixel location of the points. This was done in order to determine the true location of the points with respect to the origin. The number of pixels along the X and Y were determined and was compared to the physical values on the graph. Through ratio and proportion, the values of the points on the graph were determined. However, in the obtained graph, the origin is located at (9,1). Translation of the points were done to correct the values. The graph was reconstructed in Excel and was compared to the scanned graph by superimposing the two.

Figure 2. Reconstructed graph with the overlaid scanned graph.

Though the smoothing done by Excel did not fit exactly with the curve of the scanned graph, I still give myself 10 points for this activity since I was able to determine correctly the values of the points on the graph. Also, I was able to overlay the scanned image on the background of the reconstructed graph. Thanks to Cheryl Abundo for helping me change the minimum and maximum axis labels of the graph in Excel, and Xylene Azurin for helping me overlay the scanned graph.