Introduction
The project aims to recreate and preserve historical artifacts from the Slavery in the Old South display at the MeekEaton Southeastern Regional Black Archives Research Center and Museum (Black Archives) at FAMU. Creating accurate 3D models of the artifacts allows the artifacts to be displayed on the internet for greater access. Because of the easier virtual access to these artifacts, the museum hopes that it will increase the community's engagement in these historical findings. In addition to the academic advantages, it is possible to possible replication of the artifacts for display while preserving the originals.
To create these 3D models, the current design is a scanning system that converts 2D pictures of an object to a 3D Model.
The Process
The frame acts as an isolator for the artifacts that are being photographed. This is to reduce the environmental noise that appears when taking the photos. To achieve an enclosed artifact, an acrylic bed or fishing line is used to suspend the artifact during photographing. To illuminate the artifact, diffused lighting lights the artifacts evenly from the outside of the frame. This allows for even lighting.
Pictures are captured with a high resolution camera such as the camera on a smartphone with at least 5 megapixel camera or with a video. If video is used, it should be captured at 1280 x 720 at least. Higher resolution produces greater detail but pictures over 10-12 megapixel may slow the computations due to the size. Motion blur becomes a concern after converting the video to pictures and should be removed to maintain artifact clarity.
After the pictures are taken, they are passed into VisualSFM. VisualSFM creates a sparse and dense point cloud using the images. After VisualSFM, the project that is generated by VisualSFM's dense reconstruction is used by MeshLab to create a textured mesh. This process requires manual cleaning of the noise to achieve the best results. The mesh created by MeshLab can be used in animation and 3D printing if the mesh is accurate enough.
This process is described in greater details in the user manual here.
The Design
The design that has been decided upon is a PCV frame that acts as an isolated environment. The remaining components of the design are the camera, a cover, lights, and an acrylic bed.
Frame
The frame is made of 1 1/4 inch PVC pipe. The outer dimensions are 64.5" x 52.5" x 66.5" for the length, width, and height respectively
It has 26 pieces: 8 of which are joints, the other 18 are PVC pipes.
Camera
With the current design a single camera is used. Due to cost constrains and complex nuances of objects, this allows for full freedom
when taking pictures. Pictures should have 60 percent of overlap or more to allow for matching between pictures. The camera has a
resolution of at least 5 megapixels to record the details of the artifacts. Videos provide a quicker method for achieving a high overlap
and good quantity of pictures. However, the quality of those pictures can be skewed due to motion blur. These images should be removed as
the blurriness will degrade the quality of the scan. A video of 1280 x 720 resolution was used for image capture when video was chosen. Higher
resolution will give greater details though.
Cover
The chroma key cloth is a solid color usually green. It is used in film studios to replace backgrounds and is better known as a green screen.
The purpose of the green screen is to allow the software to take away the background reducing the amount of clutter that is not the object being scanned.
This will be placed on the inside to keep the background consistent.
After testing with green screen, color spillage had become an issue during photographing. The design instead uses a white background to eliminate
color spillage. The background also aids in isolating the artifact from the outside by providing a barrier.
Lighting
The goal for the lighting is to keep the object evenly illuminated with as natural light as possible without exposing the object to sunlight.
The lights that are used are from a studio lighting setup. These lights provide full spectrum compact fluorescent lights with diffusion umbrellas
to keep the light scattered and evenly illuminates the artifact being scanned.
Acrylic Bed
The polished acrylic bed is made from an acrylic plate that measures 4.5'x2'x0.5" with two acrylic strips along the side that have been bonded to the
bed and act as a brace to prevent the bed from bending. The acrylic bed acts as a clear platform to scan artifacts from all angles.
Budget
| Material Used | |||
|---|---|---|---|
| Item | Amount | Price | Total |
| Polished Acrylic | 1 | $221.25 | $221.25 |
| PVC Pipe | 12 | $2.25 | $27.00 |
| PVC Elbow | 8 | $1.19 | $9.52 |
| PVC Tee | 8 | $1.74 | $13.92 |
| Fluorescent Lights with Umbrella Diffusors Kit | 1 | $47.51 | $47.51 |
| White Translucent Cover | 2 | $2.00 | $4.00 |
| Sub Total | $323.20 | Material Not Used | |
| Green Screen Muslin | 2 | $15.00 | $30.00 |
| LED Strips | 2 | $53.93 | $107.86 |
| LED Power Adapter | 2 | $23.70 | $23.70 |
| Sub Total | $161.56 | ||
| Total | $484.76 |