HemoVision Quick Start Guide

This Quick Start will guide you through your first HemoVision project. We will use the demo data from the Single Wall scene. The images for this project can be downloaded from the Demo Data page.

If you want to learn more about how the photographs were taken, have a look at our Scene Documentation page.

Creating a Project

Let's start by creating a new project by going to:

File > Create Project

Similarly, you can use the Ctrl+N shortcut. Enter a project name (required) and a project location (optional) and click OK. We will name our project 'Demo Project' and leave the location empty. Once created, the project will show in the project browser on the left hand side.

Creating a Room

Before adding a zone, we first create a room to which we can add our zone. Do this by going to:

Edit > Add Room

Enter a room name (required) and room location (optional) in the popup window, and click Add Room. We will name our room 'Room 1' and leave the location empty. The room will appear in the project browser as a child of our project.

Creating a Zone

Next, we can add a new zone to our room. A zone is location within the room that has been documented (photographed) according to HemoVision principles (see our Scene Documentation page for more info about the documentation principles). To add a zone, go to:

Edit > Add Zone

In the popup window, complete the following steps:

1. Select your room ('Room 1') from the dropdown menu at the top.
2. Enter a zone name (required) and location (optional). We will name our zone 'Zone 1' and leave the location empty.
3. Import all overview images from your data folder. You can import images using the 'Import Images' button at the bottom of the window. Alternatively, you can drag and drop your images directly into the popup window.

Note: When reconstructing a zone from a single image, all markers must be placed on the same flat surface! When markers are placed on multiple surfaces, use multiple overview images from different perspectives. For more information, read our Scene Documentation page.

1. Click Reconstruct Zone at the bottom to start the reconstruction process. First, all images will be processed individually, after which the zone reconstruction is created. Once all individual steps are highlighted in green, processing has finished and a preview of the reconstruction will be shown in the 3D view.

   

2. Next, we can specify the overview marker location and its corresponding transformation. For now, set the marker location to 'Vertical Wall', and set the Y-translation to 1170mm. Leave all other values at their default value.

   

3. Click Add Zone to add the zone to your room. The zone will appear in the project browser as a child of Room 1. The 3D markers will be displayed in the 3D view.

   

Adding Detail Images

We now have our zone structure, but we cannot add any bloodstains yet. For this, we need to add detailed close-up images of the bloodstains by going to:

Edit > Add Detail Image(s)

In the popup window, complete the following steps:

1. Select 'Room 1' from the first dropdown menu.
2. Select 'Zone 1' from the second dropdown menu.
3. Import (all) detail images using the 'Import Images' button at the bottom, or by dragging and dropping the images inside the popup window.

4. Click Analyze Images to start processing the images. HemoVision will detect all markers in the images, and correct for any perspective distortion that is present. Once completed, all the individual steps are highlighted in green.

   

5. Once completed, click Add to Zone to add the images. The detail images will appear as children of 'Zone 1' in the project browser. The images will also be displayed in the 3D view.

   

Adding Stains

Create Stain Group

Stains in HemoVision are grouped into stain groups. So, before we can add stains, we first need to add a stain group by going to:

Edit > Add Stain Group

In the popup window, select the room to which you want to add the group ('Room 1') and specify a group name (we use 'Group 1' here). Finally, select the color that will be used to draw the stains in the 2D and 3D view.

Add stains

Now that we've added a stain group, we can add stains to this group. First switch to the 2D-view by clicking the 2D-icon in the toolbar at the top of the application. Then, select a detail image in the project browser on the left. Alternatively, you directly open up a detail image by double clicking on an image in the 3D view.

Next, look for a suitable bloodstain. You can zoom in on a stain by holding down the Ctrl-key and scrolling your mouse wheel. Panning the image is done by holding down the Ctrl-key dragging your mouse while holding down the left mouse button.

Once you have identified a suitable stain, you can analyse it using one of three methods. Select one of the three available methods by clicking the stain icons in the toolbar at the top of the application. The dropdown menu in the toolbar can be used to select the stain group to which you want the add stains. Note that the 2D-view displays some info on how to use each method at the bottom-right

1. Automatic Stain Analysis (Point):

Analyse stains with a single click. Once this method has been selected, your cursor will change to a cross. To analyse a bloodstain, simply click inside it. The method will automatically analyse the shape of the bloodstain, and estimate its impact and glancing angles. Here's a few tips when using this method:

• Select stains that have a homogenous color.
• Click inside the stain, but more towards the tip of the stain.
• Right-click on a stain to delete it.

2. Automatic Stain Analysis (Line):

Analyse stains using two clicks. Once this method has been selected, your cursor will change to a cross. To analyse a bloodstain, first click inside the bloodstain towards the tip of the stain (similar to the single-click analysis above), and click a second time towards the tail of the stain. Note that this line does not need to be very precise. The method will automatically analyse the shape of the bloodstain, and estimate its impact and glancing angles. Here's a few tips when using this method:

• Select stains that have a homogenous color.
• Right-click during line drawing to cancel.
• Right-click on a stain to delete it.

3. Manual Ellipse Analysis

Analyse stains with three clicks. Once this method has been selected, your cursor will change to a cross, and you will be able to place an ellipse over the stain. First click on the edge front edge of the stain (tip), then click at the end of the body of the stain (exclude the tail), and finally click on the side of the stain. Right-clicking during ellipse-drawing will cancel the process. Once the stain has been placed, you can always edit it by selecting the stain and using the handles (to select a stain, make sure your do not have any of the stain analysis methods active).

• Right-click during ellipse drawing to cancel.
• Right-click on a stain to delete it.
• You can adit manual ellipses by selecting them.

You can add as many stains as you like, in any detail image. Simply switch between detail images using the project browser. Once you have sufficient stains, the 3D view should something like this:

Calculating AOO

Finally, we can add an area of origin (AOO) to our project. To do so, go to:

Edit > Add AOO

In the popup window, complete the following steps:

1. Select to room to which the AOO is added ('Room 1').
2. Select the stain group(s) that are used for the AOO calculation ('Group 1').
3. Select the AOO calculation method from the dropdown menu ('Linear Least-Squares Angles').
4. Leave the checkbox 'Auto Update' checked.
5. Specify a color for the AOO.

Click OK to add the AOO to the project. The AOO will be visible in the 3D view, as shown below:

Congratulations, you have successfully analysed your first area of origin with HemoVision!