Assignment 4: Image Manipulation

by jemerson122

When it comes to manipulating a digital image, the possibilities are endless.  Adobe Photoshop has allowed me to manipulate a black and white picture taken in Cinque Terre, Italy in the Fall of 2011. Through the use of point operations and neighborhood operations, I managed to give the photograph a completely different look.

Point operations can either be unary or binary. In this case, I used unary point operations because I am dealing with a single image as opposed to combining two images to make a resulting image. More specifically, numeric transformations are useful unary point operations that are applied to each pixel in the input image. Two different numeric transformations were used to manipulate the original image: contrast function and image threshold function, respectively.

First, I chose to increase the contrast to 100% because there were too many middle tones in the photograph. Applying the contrast function made dark areas of the input image even darker while the bright areas became brighter. To be more specific, lower intensity values are mapped to 0 while high intensity values are mapped to the maximum value of 255. The values in between are distributed in between 0 and 255.

Next, I applied the image threshold function to the input image. However, I did not increase or decrease the threshold level once turned on. The strong light source and the reflection on the surface of the water created a nice balance of dark and light color so I left the slider in the middle at 128. Consequently, all input values below the threshold value of 128 are set to the minimum value of 0, making them black. On the other hand, the input values above 128 will be set to the maximum value of 255, making them white. Taking out the gray tones in the image gave it a sharp, harsh feel and really brought attention to the rocks. The memories in the photograph revolved around cliff jumping, so I wanted the cliffs and myself to really jump out at the viewer.

After applying the point operations, I used a neighborhood operation, which combines information from a region of input image pixels in order to create each new output image pixel. Geometric transformations are just one class of neighborhood operations. By applying the geometric neighborhood transformation of image warping to my original image, I created a “fish-eye” view. I stretched each corner of the middle square outward to get this effect. Throughout our adventures in Italy, a friend of mine had a GoPro camera that she strapped to her wrist when we were cliff jumping. Later, we made a video of our experiences and they all had the fish-eye effect because of the device she used. The image warping reminds me of a still frame from the recorded memories in Cinque Terre, Italy.