Visual Attention Lab

Data Sets and Stimulus Sets

"Shuffle" Stimulus Set

There is a long line of research that has looked at how how we detect change. Typically, change detection experiments use a set of two images that are identical except for one element that has been removed from one image but not the other. Observers are then asked to identify which item has been manipulated in these images. We have compiled a set of images used in a change detection experiment. What is unique about this image set is that we have an original image as well as a "shifted image." This shifted image has a slight rotation in angle as compared to the original image, and allowed us to test how well observers could detect an object being added or removed from a scene, when both scenes are presented at different angles.

Stimulus Details

The image sets available for download contain pictures of real-world scenes, some domestic and some retail. For the most part, the scenes are indoors, but there are a few outdoor scenes in the set. All of the images have been resized to 600 x 450 pixels.

For each scene, there are three photographs: one image which is the “original” image, and two images that are the comparison images. One of these comparison images is the exact same as the original image save for a slight shift in the angle from which the photo was taken. The other comparison image is the same as the first comparison image with one object removed. Thus a change in this experiment is defined as the addition or removal of an object from the scene, but does not include changes in the viewpoint of the photo.

The images are organized into three folders based on the angle difference between the original image and the two comparison images. In the smallShift folder, after taking the original image, the camera was tilted slighty to the side or to the front, and then the two comparison images were taken. In the largeShift condition, a large step was taken between the original and the two comparison images. In the noShift folder, all three images per set were taken from a tripod which stayed in the same location between shots.

The images in the smallShift set were taken with a Nikon Coolpix S3 digital camera, and those in the largeShift and noShift were taken with a Panasonic DMC-LX5 digital camera.

Note on Nomenclature

In the image folders available for download, all three images of the same scene have the same root name, say "imageName". We used suffixes to indicate which version of the scene the photo represents. So "imageName_01" is the original image, "imageName_02" is the comparison image where nothing was removed, and "imageName_change" is the comparison image with an object removed.

Downloading the Image Set

A folder for each type of image is available for download below. In order to "unzip" the folder containing the images, double click on the zip file after downloading it. A list of the XY coordinates of changes in angle for the images is also available for download.

XY Coordinates of angle change between images [EXCEL]

No Change Images [.ZIP file]

Small Change Images [.ZIP file]

Large Change Images [.ZIP file]

If you decide to work with these images, we would be interested to hear what you are up to. Please drop a note to