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# [User Study] inSpectr

InSpectr: A tool for multi-modal exploration, visualization, and analysis of spectral data.

## Introduction

This questionnaire aims to evaluate a software prototype for multi-modal exploration, visualization and analysis of spectral data. Your feedback will be part of a submission for the Eurographics Conference on Visualization 2014. You will be shown several visualizations of scalar and spectral data. You will then be asked to perform some simple analysis tasks using these visualizations. Furthermore you will be asked about how well-suited the visualizations were for the task at hand. This study will be divided in two parts based on the two different data sets used for the evaluation. Note: there will be video materials demonstrating some interactive concepts. Please watch them full-screen and in 720p if possible. If there is no full-screen button on your embedded video, please open it in another tab. Note 2: If some images seem small to you please zoom-in in your browser.

## General Questions

Questions to determine your experience level with the used techniques and methods
Your name:
This is a required question
Your affiliation:
This is a required question
How often do you work with Computed Tomography data?
Mark only one oval.

- At least once a year
- At least once a month
- At least once a week
- Daily
- Never

This is a required question
How often do you work with spectral data (XRF, EDS, WDS, EELS, ...)?
Mark only one oval.

- At least once a year
- At least once a month
- At least once a week
- Daily
- Never

This is a required question
How much experience (in months) do you have with multi-modal visualizations (i.e. the visualization of data from multiple measurement methods alongside each other)?
Must be a number
This is a required question

## Available views

We use variety of views to visualize different aspects of our data sets. For each data set, there is a high-resolution 2D or 3D image with scalar data (obtained via CT) and an according 2D/3D "image" with an energy spectrum per pixel/voxel, in a lower resolution than the CT data.

## Views used in this evaluation:

## Part I: 2D XCT/XRF Phantom

This part uses a real 2D scan of a water phantom containing cylinders with certain element(s) in them. Two modalities are available: X-ray computed tomography ( XCT) and X-ray fluorescence (XRF). Please click "Continue" to proceed with the evaluation.

## Aggregated Spectrum

Aggregated spectrum is a representation which is aggregating the spectral information of every point in the data set. It takes the energy spectrum function of every point and computes the maximum value of these functions for every energy bin. The resulting function is then displayed. The following illustration shows 3 individual spectra of different materials in 3 different positions and the resulting aggregated spectrum. Please inspect the illustration and then answer the questions following it. Note: the shape shown with the dotted line is imposed by Compton scattering and should not be counted as a peak.

##

How many characteristic energy peaks do you see in the first local spectrum (top-most, red)
Mark only one oval.

- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8

This is a required question
How many characteristic energy peaks are in the second local spectrum (middle, red)
Mark only one oval.

- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8

This is a required question
How many characteristic energy peaks are in the third local spectrum (bottom, red)
Mark only one oval.

- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8

This is a required question
How many characteristic energy peaks there are in the aggregated spectrum (bottom-most, gray)
Mark only one oval.

- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8

This is a required question
Do you think that aggregated spectrum is:
Mark only one oval.

- showing some but not all local peaks of the given individual spectra
- showing all the local peaks of the given individual spectra
- showing more local peaks than all of the given individual spectra

This is a required question

## Interactive Spectrum Probing

We would like to ask you now for evaluation of the interactive spectrum probing technique. It utilizes linked slicer and spectral views. When the user is moving the cursor over the slice view the spectral function corresponding to the point under the cursor is displayed in the spectral view (red). The accumulated spectrum is shown in gray for the context. The following video illustrates the interactive spectrum probing. Please watch the video and then answer the questions following it.

##

http://youtube.com/watch?v=yLgbtg7_rfM
Demo: Interactive Spectrum Probing
Rate the difficulty of recognizing the peaks corresponding to the 4 different circular regions(white)?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
impossible Select a value from a range of 1,impossible, to 5,absolutely effortless,. |  |  |  |  |  | absolutely effortless

This is a required question
What is you opinion about the spectral characteristics of the 4 circular regions?
Mark only one oval.

- All 4 are the same (same peaks)
- All 4 are different (different peaks)
- 3 regions are different and the 4th is the mixture of these 3
- 3 regions are the same, but 1 is different

This is a required question
How would you rate the usefulness of the interactive probing for performing explorational tasks?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
useless Select a value from a range of 1,useless, to 5,very useful,. |  |  |  |  |  | very useful

This is a required question

## Selections in Spectral Domain

We allow the selections made directly in the spectral view. Linked views are used: 2D slice/3D volume and spectral view. The selection is specified using the red boxes that user can place on the spectral view using the cursor. The regions of the specimen with spectral functions satisfying the selection are highlighted in red. The following video illustrates the interactive selection in spectral domain. Please watch the video and then answer the questions following it.

##

http://youtube.com/watch?v=IONY4ioDZ9k
Demo: Selection in the Spectral Domain
What is you opinion about the spectral characteristics of the 4 circular regions?
Mark only one oval.

- All 4 are the same (same peaks)
- All 4 are different (different peaks)
- 3 regions are different and the 4th is the mixture of these 3
- 3 regions are the same, but 1 is different

This is a required question
How would you rate the usefulness of the selections for performing explorational tasks?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
useless Select a value from a range of 1,useless, to 5,very useful,. |  |  |  |  |  | very useful

This is a required question

##

##

Using given selections please assign the energy peaks to regions of interest
Region 1
Check all that apply.

- A
- B
- C
- D
- E
- F

This is a required question
Region 2
Check all that apply.

- A
- B
- C
- D
- E
- F

This is a required question
Region 3
Check all that apply.

- A
- B
- C
- D
- E
- F

This is a required question
Region 4
Check all that apply.

- A
- B
- C
- D
- E
- F

This is a required question

## Transfer Function Design Using Spectral Data

We allow the user to design a transfer function (TF) using the spectrum view. The colors can be assigned to the different positions of the energy spectrum. Then every point's spectral function is accumulating the colors. This results in a color, which is then assigned to the point. The following video demonstration shows the user interactions required to specify the transfer function (TF) as well as the intermediate and final results. Please watch the video and answer the questions below.

##

http://youtube.com/watch?v=3GU2OwNg8Uc
Demo: Transfer Function Design Using Spectral Data
How would you rate the transfer function for performing explorational tasks?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
useless Select a value from a range of 1,useless, to 5,very useful,. |  |  |  |  |  | very useful

This is a required question
How would you rate the difficulty of the TF design process?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
non-intuitive, difficult Select a value from a range of 1,non-intuitive, difficult, to 5,intuitive, easy,. |  |  |  |  |  | intuitive, easy

This is a required question

## Final manually created transfer function and the resulting visualization:

##

http://youtube.com/watch?v=9IguxfLIvEY
XCT/XRF transition using the given transfer function
How many different material clusters do you see
Mark only one oval.

- none
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- more than 7

This is a required question
What is you opinion about the spectral characteristics of the 4 circular regions?
Mark only one oval.

- All 4 are the same (same peaks)
- All 4 are different (different peaks)
- 3 regions are different and the 4th is the mixture of these 3
- 3 regions are the same, but 1 is different

This is a required question
Rate the difficulty of identifying different material clusters using this visualization.
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
impossible Select a value from a range of 1,impossible, to 5,absolutely effortless,. |  |  |  |  |  | absolutely effortless

This is a required question

## Advanced Spectral Visualizations

We present semi-transparent spectra lines and spectra histograms to reflect additional information on the spectral view. The semi-transparent spectra lines visualization is displaying a high number of transparent lines for individual spectra of all the points in the data set. The spectra histograms visualization is building a histogram at each energy bin. It shows the number of individual spectra that are having a similar photon count number. The color map is then applied to visualize the resulting histograms. The following illustration demonstrate these techniques. Please inspect the illustration and answer the following questions.

##

Rate the ability to estimate the density of the individual spectrum functions using semi-transparent lines.
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
very difficult Select a value from a range of 1,very difficult, to 5,very easy,. |  |  |  |  |  | very easy

This is a required question
Rate the ability to estimate the density of the individual spectrum functions using spectra histograms.
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
very difficult Select a value from a range of 1,very difficult, to 5,very easy,. |  |  |  |  |  | very easy

This is a required question
How would you rate the semi-transparent spectra lines for performing explorational tasks?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
useless Select a value from a range of 1,useless, to 5,very useful,. |  |  |  |  |  | very useful

This is a required question
How would you rate the spectra histograms for performing explorational tasks?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
useless Select a value from a range of 1,useless, to 5,very useful,. |  |  |  |  |  | very useful

This is a required question

## Analysis Using Elemental Composition Maps

After elemental decomposition is performed using the raw spectral data, the diverse set of visualizations can be employed to perform the quantitative analysis. In the following each technique will be presented with an illustration or a video demonstration. Please go through the explanatory material and then answer the following question for each visualization technique.

## Element Maps

How easy was it to derive quantitative composition information (e.g., how much of which elements are present) at some position using the visualization
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
I could not derive it Select a value from a range of 1,I could not derive it, to 5,I could derive it effortlessly,. |  |  |  |  |  | I could derive it effortlessly

This is a required question
Rate the ability to derive individual distributions of each present element
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
I could not derive it Select a value from a range of 1,I could not derive it, to 5,I could derive it effortlessly,. |  |  |  |  |  | I could derive it effortlessly

This is a required question

## Pie-Chart Glyphs

How easy was it to derive quantitative composition information (e.g., how much of which elements are present) at some position using the visualization
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
I could not derive it Select a value from a range of 1,I could not derive it, to 5,I could derive it effortlessly,. |  |  |  |  |  | I could derive it effortlessly

This is a required question
Rate the ability to derive individual distributions of each present element
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
I could not derive it Select a value from a range of 1,I could not derive it, to 5,I could derive it effortlessly,. |  |  |  |  |  | I could derive it effortlessly

This is a required question
How would you rate the multi-modal aspect of the technique? (XCT/spectral) How easy was it to mentally map them to each other, compare them, and to derive information from both?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
very difficult to map / derive information from Select a value from a range of 1,very difficult to map / derive information from, to 5,very easy to map / derive information from,. |  |  |  |  |  | very easy to map / derive information from

This is a required question

## Probing Material Composition: Pie Chart

http://youtube.com/watch?v=y4Xh96i9VZQ
Demo: Probing Material Composition: Pie Chart
How easy was it to derive quantitative composition information (e.g., how much of which elements are present) at some position using the visualization
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
I could not derive it Select a value from a range of 1,I could not derive it, to 5,I could derive it effortlessly,. |  |  |  |  |  | I could derive it effortlessly

This is a required question
Rate the ability to derive individual distributions of each present element
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
I could not derive it Select a value from a range of 1,I could not derive it, to 5,I could derive it effortlessly,. |  |  |  |  |  | I could derive it effortlessly

This is a required question
How would you rate the multi-modal aspect of the technique? (XCT/spectral) How easy was it to mentally map them to each other, compare them, and to derive information from both?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
very difficult to map / derive information from Select a value from a range of 1,very difficult to map / derive information from, to 5,very easy to map / derive information from,. |  |  |  |  |  | very easy to map / derive information from

This is a required question

## Probing Material Composition:Periodic Table

http://youtube.com/watch?v=GviAeILJwao
Demo: Probing Material Composition using Periodic Table
How easy was it to derive quantitative composition information (e.g., how much of which elements are present) at some position using the visualization
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
I could not derive it Select a value from a range of 1,I could not derive it, to 5,I could derive it effortlessly,. |  |  |  |  |  | I could derive it effortlessly

This is a required question
Rate the ability to derive individual distributions of each present element
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
I could not derive it Select a value from a range of 1,I could not derive it, to 5,I could derive it effortlessly,. |  |  |  |  |  | I could derive it effortlessly

This is a required question
How would you rate the multi-modal aspect of the technique? (XCT/spectral) How easy was it to mentally map them to each other, compare them, and to derive information from both?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
very difficult to map / derive information from Select a value from a range of 1,very difficult to map / derive information from, to 5,very easy to map / derive information from,. |  |  |  |  |  | very easy to map / derive information from

This is a required question

## Spectral Magic Lens

http://youtube.com/watch?v=b8m2PCmmj8c
Demo: Spectral Magic Lens
How easy was it to derive quantitative composition information (e.g., how much of which elements are present) at some position using the visualization
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
I could not derive it Select a value from a range of 1,I could not derive it, to 5,I could derive it effortlessly,. |  |  |  |  |  | I could derive it effortlessly

This is a required question
Rate the ability to derive individual distributions of each present element
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
I could not derive it Select a value from a range of 1,I could not derive it, to 5,I could derive it effortlessly,. |  |  |  |  |  | I could derive it effortlessly

This is a required question
How would you rate the multi-modal aspect of the technique? (XCT/spectral) How easy was it to mentally map them to each other, compare them, and to derive information from both?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
very difficult to map / derive information from Select a value from a range of 1,very difficult to map / derive information from, to 5,very easy to map / derive information from,. |  |  |  |  |  | very easy to map / derive information from

This is a required question

## Part II: Alloys (TP09)

The dataset used in this part is a combination of a real 3D X-ray computed tomography (XCT) scan of the test part 9 (TP09) specimen, and 3D X-ray fluorescence (XRF) virtually generated using known reference spectra of chemical elements. We have imitated a specimen made of brass (copper+zinc). The composition of the brass alloy is varying across the object. Please click "Continue" to proceed with the evaluation.

## Global Composition

We provide an aggregated spectrum to provide information about the global composition of an object. When viewed together with reference spectra of elements, it can already provide a good first start on the elemental distribution in the specimen. An elemental decomposition of the spectrum makes the concentration values of each element available, which can be visualized in the form of a pie chart.

##

##

With the information given above, what is the average composition of the specimen?
Mark only one oval.

- Copper ~1% / Zinc ~99%
- Copper ~25% / Zinc ~75%
- Copper ~52% / Zinc ~48%
- Copper ~80% / Zinc ~20%
- Copper ~100% / Zinc ~0%

This is a required question

## Local Composition

To determine the local composition at places of interest, we can show the spectrum at a voxel hovered over in any of our slicers.

##

##

##

Is the Copper concentration at the location selected in the slicer higher or lower than the average, or equal to the average?
Mark only one oval.

- Higher
- Lower
- Equal

This is a required question
How easy was it to compare a local spectrum to the aggregate spectrum?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
It was not possible to get good information Select a value from a range of 1,It was not possible to get good information, to 5,It was very easy to obtain information,. |  |  |  |  |  | It was very easy to obtain information

This is a required question
How would you rate the multi-modal aspect of the technique? (XCT/spectral) How easy was it to mentally map them to each other, compare them, and to derive information from both?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
very difficult to map / derive information from Select a value from a range of 1,very difficult to map / derive information from, to 5,very easy to map / derive information from,. |  |  |  |  |  | very easy to map / derive information from

This is a required question
This is a required question

## Selection

Below are several selections in the spectrum. The selection in the spectrum function is marked with the red rectangle. The spectrum function also shows the reference spectra of selected elements (according to the given legend). All voxels for which the spectrum passes through the selected region are highlighted in red in the slicers and the 3D view.

##

## Selection in Spectrum - Example 01

In the above picture, which regions are selected?
Mark only one oval.

- Regions with high concentration of copper
- Regions with low concentration of copper
- Regions with high concentration of zinc
- Regions with low concentration of zinc

This is a required question

## Selection in spectrum view - Example 02

In the above picture, which regions are selected?
Mark only one oval.

- Regions with high concentration of copper
- Regions with low concentration of copper
- Regions with high concentration of zinc
- Regions with low concentration of zinc

This is a required question
When looking at the slicer/3D renderer visualization of the selection, how well-informed do you feel about where in the specimen those regions are?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
badly informed Select a value from a range of 1,badly informed, to 5,very well informed,. |  |  |  |  |  | very well informed

This is a required question
How would you rate the multi-modal aspect of the technique? (XCT/spectral) How easy was it to mentally map them to each other, compare them, and to derive information from both?
Mark only one oval.

| 1 | 2 | 3 | 4 | 5 |
very difficult to map / derive information from Select a value from a range of 1,very difficult to map / derive information from, to 5,very easy to map / derive information from,. |  |  |  |  |  | very easy to map / derive information from

This is a required question

## Thank you!

That's it! We would like to thank you very much for taking your time to participate in this questionnaire! You will be able to edit your answers for at least one more day. Have a great day!
Do you have additional comments?
If you have any additional comments, critics, or suggestions, please enter them here
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