Designs

Sally is a college freshman. She notices that she spends a lot of time walking to and from her dorm and classes, and so she decides to purchase a bike. She doesn’t know much about them, and isn’t interested in spending a lot of time looking up reviews at home; instead, she simply goes to the nearest bike shop.

With assistance from a salesman, she tries a number of bikes, and eventually narrows down her options to several different brands and models. She likes all of them, but can’t decide. She'd like an efficient way to look up and compare information on each. She already at the store, and wants to go home with a bike, not come back after looking up reviews at home on her laptop.  She takes out her iPhone and opens Schnap It!

Design A

Sally individually takes a picture of each bike:

And then quickly identifies where in the picture the bike is by using gestures to draw a bounding rectangle, ellipse, circle, or freehand hull.  Specifically, this will be a touch and drag interface specifying exactly where the principal points of the shape should be in the picture taken.

All her pictures are aggregated into a grid, where she can select multiple to review at the same time:

Having selected the bikes of interest, the program opens a Reviews Shopping Cart," which contains a row for each selected bike, along with it’s automatically-determined brand and model number, it’s lowest price from a reliable vendor, and it’s rating from a reliable reviews site. Sally notices that although the Schwin (bottom row) is only $99 online (perhaps it is $169 at the store), that it is also only rated one star.

She decides to get more information about the more expensive, but highly-rated Trek bicycle. To do so, she taps on the arrow in the Reviews Shopping Cart. This brings her to a page that shows price, description, and collections of reviews. After scanning it, she is decides to buy the Trek, right there in the store.

Analysis - Design A

Efficiency

In this design, the user has a different screen for each decision.  The user also must individually take pictures of each object. Then when all of the pictures have been taken, the user decides which objects to review together.  This isn't the most efficient design since the user isn't likely to take pictures of products she isn't interested in.  Efficiency can be improved by aggregating the 'snap picture' and 'choose objects to review' subtasks into less screens.  For instance, one picture could be taken and the very next screen shows the shopping cart with information about each object specified.

For the purposes of this application, the user must spend time annotating the picture to specify which object to review.  The method of annotation in this design is very efficient.  The method of comparing objects is moderately efficient; if the user wants to compare a specific detail about two objects they must travel back and forth between detail screens.  The user does not have the ability to move that detail to the Reviews Shopping Cart where all objects and main details (such as stars) can be viewed.

Learnability

Given this application starts by going right to the camera, the user may not know exactly what to do the first time they use the application.  We could use a first-use tutorial, or else let them learn by taking a random picture and going through the process to figure out how the application works.  This latter scenario detracts from the initial learnability of the application, because there are no blatant instructions for the user to read.  In the long run, the user does not have to bypass a repetitive start or instruction screen.  After taking a picture, the user can touch randomly to learn exactly how to specify which object they are interested in.  After specifying, the application reinforces exactly how to take pictures of object and annotate by allowing the simple process to be repeated.  This also gives the user practice.  Selecting which objects to review is fairly easy to learn.  The pictures selected on the grid will be highlighted to provide a selection affordance to the user.  The arrows on the Reviews Shopping Cart clearly afford a page of additional details.  In all, the learnability of this design is fairly good.  It allows the user to learn by experimentation and stays out of their way.

Safety

Since the efficiency of iPhone applications is very good, the user can correct mistaken view changes fairly quickly by hitting the back button to move up the screen hierarchy.  Software architecture on the iPhone make this easy to implement and allows the user to efficiently recover from errors.  The user cannot modify information displayed about the objects, separating the backend model from the user model.  To the user, the application allows a way to quickly look up products and a simple way of comparing specifics.  Errors may occur in the backend, such as the object being misrecognized, but this design assumes that willl not happen.  Modifications could be made for the case when a new object is specified that is not in the database or when the picture taken is not of high enough quality to work for the object detector.

Design B

This time, Sally can collect information about all the products she’s interested in more quickly by taking pictures that each have multiple bicycles in them:

For each picture, she indicates where each bike by outlining them with her finger:

She is automatically taken to the scrollable Reviews Shopping Cart, where the bicycles of interest are aggregated, and show best, reliable online prices and reviews.

As before, she can look up more detailed information (description, multiple reviews and prices) about each bike by clicking on the arrow.

Analysis - Design B

Efficiency

The efficiency has greatly improved from design A.  The user does not have spend time taking a picture for each product he/she would like to view.  There is no pre-review selection page; objects detected are automatically loaded as products the user is interested in.  However, the tracing arguably takes longer to annotate an object than the touch and drag method.  There is no obvious way to modify the outline of the object - the user would have to restart tracing all over again.  Apart from the more complicated annotation method, the efficiency of the application has improved by making decision making more simple.

The efficiency issue of comparing a rare or usually unimportant detail still remains: the user would have to travel back and forth between detail pages.  Another case in which the design functions poorly in is if the user has to rearrange the products so that he/she can take a picture with all of the products inside the frame.  In this case, it would be easier to just take a multiple of pictures.  This design does not allow for multiple pictures to be in the same compare screen.

Learnability

Learnability has decreased in some respects compared to design A. The user must innately know to take a picture that incorporates several objects and annotate them in the same frame, or accidentally learn that the application allows for this.  The user can also learn about this feature by watching other users.  This is the only feature that is not obvious, and small instruction blurbs 'draw to annotate product(s)' would benefit he learnability of the application.  We could also add certain affordances, like animations drawing sample figures around objects.  Otherwise, the user should not have a hard time learning that certain buttons on the compare screen bring up more details about that product.  

Safety

Design C

Rather than take a picture of the bike, she simply takes a picture of it’s barcode. This does not require any annotation.

Once Sally has taken pictures of each barcode, she can compare them in a table by price, reviews, warranty, etc. Since the software can determine that bikes are being compared (based on the product classification of each bar code), it can also provide additional values that can be compared on, such as construction materials (e.g. tire type). Sally is most interested in comparing the warranties for each bicycle, so she taps that:

...And is taken to a table where each bike she imaged is compared.

Epilogue

Armed with the knowledge of external reviews and competitive pricing, Sally is confidentally able to select the bike that best fits her needs.