AUGMENTED REALITY (AR)

October 13, 2017


Depending on the location, you can ask just about anybody to give a definition of Virtual Reality (VR) and they will take a stab at it. This is because gaming and the entertainment segments of our population have used VR as a new tool to promote games such as SuperHot VR, Rock Band VR, House of the Dying Sun, Minecraft VR, Robo Recall, and others.  If you ask them about Augmented Reality or AR they probably will give you the definition of VR or nothing at all.

Augmented reality, sometimes called Mixed Reality, is a technology that merges real-world objects or the environment with virtual elements generated by sensory input devices for sound, video, graphics, or GPS data.  Unlike VR, which completely replaces the real world with a virtual world, AR operates in real time and is interactive with objects found in the environment, providing an overlaid virtual display over the real one.

While popularized by gaming, AR technology has shown a prowess for bringing an interactive digital world into a person’s perceived real world, where the digital aspect can reveal more information about a real-world object that is seen in reality.  This is basically what AR strives to do.  We are going to take a look at several very real applications of AR to indicate the possibilities of this technology.

  • Augmented Reality has found a home in healthcare aiding preventative measures for professionals to receive information relative to the status of patients. Healthcare giant Cigna recently launched a program called BioBall that uses Microsoft HoloLense technology in an interactive game to test for blood pressure and body mass index or BMI. Patients hold a light, medium-sized ball in their hands in a one-minute race to capture all the images that flash on the screen in front of them. The Bio Ball senses a player’s heartbeat. At the University of Maryland’s Augmentarium virtual and augmented reality laboratory, the school is using AR I healthcare to improve how ultrasound is administered to a patient.  Physicians wearing an AR device can look at both a patient and the ultrasound device while images flash on the “hood” of the AR device itself.
  • AR is opening up new methods to teach young children a variety of subjects they might not be interested in learning or, in some cases, help those who have trouble in class catching up with their peers. The University of Helsinki’s AR program helps struggling kids learn science by enabling them to virtually interact with the molecule movement in gases, gravity, sound waves, and airplane wind physics.   AR creates new types of learning possibilities by transporting “old knowledge” into a new format.
  • Projection-based AR is emerging as a new way to case virtual elements in the real world without the use of bulky headgear or glasses. That is why AR is becoming a very popular alternative for use in the office or during meetings. Startups such as Lampix and Lightform are working on projection-based augmented reality for use in the boardroom, retail displays, hospitality rooms, digital signage, and other applications.
  • In Germany, a company called FleetBoard is in the development phase for application software that tracks logistics for truck drivers to help with the long series of pre-departure checks before setting off cross-country or for local deliveries. The Fleet Board Vehicle Lense app uses a smartphone and software to provide live image recognition to identify the truck’s number plate.  The relevant information is super-imposed in AR, thus speeding up the pre-departure process.
  • Last winter, Delft University of Technology in the Netherlands started working with first responders in using AR as a tool in crime scene investigation. The handheld AR system allows on-scene investigators and remote forensic teams to minimize the potential for site contamination.  This could be extremely helpful in finding traces of DNA, preserving evidence, and getting medical help from an outside source.
  • Sandia National Laboratories is working with AR as a tool to improve security training for users who are protecting vulnerable areas such as nuclear weapons or nuclear materials. The physical security training helps guide users through real-world examples such as theft or sabotage in order to be better prepared when an event takes place.  The training can be accomplished remotely and cheaply using standalone AR headsets.
  • In Finland, the VTT Technical Research Center recently developed an AR tool for the European Space Agency (ESA) for astronauts to perform real-time equipment monitoring in space. AR prepares astronauts with in-depth practice by coordinating the activities with experts in a mixed-reality situation.
  • The U.S. Daqri International uses computer vision for industrial AR to enable data visualization while working on machinery or in a warehouse. These glasses and headsets from Daqri display project data, tasks that need to be completed and potential problems with machinery or even where an object needs to be placed or repaired.

CONCLUSIONS:

Augmented Reality merges real-world objects with virtual elements generated by sensory input devices to provide great advantages to the user.  No longer is gaming and entertainment the sole objective of its use.  This brings to life a “new normal” for professionals seeking more and better technology to provide solutions to real-world problems.

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ENCODERS

May 21, 2016


Once a month a group of guys and I get together for lunch.  Great friends needing to solve the world’s problems.  (Here lately, it’s taken much longer than the one and one-half hours we spend during our meeting.)  One of our friends, call him Joe, just underwent surgery for prostate cancer.  This is called a Prostatectomy and is done every day.  His description of the “event” was fascinating.  To begin with, the surgeon was about twenty (20) feet from the operating table. Yes, that’s correct; the entire surgery was accomplished via robotic systems. OK, why is this procedure more desirable than the “standard” procedure”?   The robotic-assisted approach is less invasive, reduces bleeding and offers large 3-D views of the operating fields. The mechanical arms for the robotic system are controlled by the surgeon and provide greater precision than the human hand.  This allows the surgeon more control when separating nerves and muscles from the prostate. This benefits patients by lowering the risk of side effects, such as erectile dysfunction and incontinence, while also completely removing cancer tissue.  The equipment looks very similar, if not identical to the one given in the JPEG below.  Let’s take a look.

Prostate Surgery and Robotic Systems

As you can see, the electromechanical devices are remarkably sophisticated and represent significant advantages in medical technology.  The equipment you are seeing above is called the “patient side cart”. It looks as follows:

Surgical Side Cart

During a robotic prostatectomy, the patient side cart is positioned next to the operating table.  The system you see above is a da Vinci robotic arm arranged to provide entry points into the human body and prostate.  EndoWrist instruments, and the da Vinci Insite Vision System, are mounted onto the robot’s electromechanical arms representing the surgeon’s left and right hands. They provide the functionality to perform complex tissue manipulation through the entry points, or ports.  EndoWrist instruments include forceps, scissors, electrocautery, scalpels and other surgical tools. If the surgeon needs to change an Endowrist instrument, common during robotic prostatectomy, the instrument is withdrawn from the surgical system using controls at the console. Typically, an operating room nurse standing near the patient physically removes the EndoWrist instruments and replaces them with new instruments.

There are certainly other types of surgery performed today using robotic systems.  Several of these are as follows:

One electromechanical device that helps to make this remarkable procedure possible is called an encoder.  Let’s define an encoder.

An encoder is a sensor of mechanical motion that generates digital signals in response to motion. As an electro-mechanical device, an encoder is able to provide motion control system users with information concerning position, velocity and direction. There are two different types of encoders: linear and rotary. A linear encoder responds to motion along a path, while a rotary encoder responds to rotational motion. An encoder is generally categorized by the means of its output. An incremental encoder generates a train of pulses which can be used to determine position and speed. An absolute encoder generates unique bit configurations to track positions directly.

As you might expect, knowing the exact position of a medical device used during surgery is absolutely critical to the outcome.  The surgeon MUST know the angular position of the device at all times to ensure no errors are made.  Nerves, tendons and muscles must be left intact.  This information is provided by encoders and encoder data systems.

ENCODER TYPES:

Linear and rotary encoders are broken down into two main types: the absolute encoder and the incremental encoder. The construction of these two types of encoders is quite similar; however they differ in physical properties and the interpretation of movement.

Incremental rotary encoders utilize a transparent disk which contains opaque sections that are equally spaced to determine movement. A light emitting diode is used to pass through the glass disk and is detected by a photo detector. This causes the encoder to generate a train of equally spaced pulses as it rotates. The output of incremental rotary encoders is measured in pulses per revolution which is used to keep track of position or determine speed.  This type of encoder is required with the medical system given above.

Absolute encoders utilize stationary mask in between the photodetector and the encoder disk as shown below. The output signal generated from an absolute encoder is in digital bits which correspond to a unique position. The bit configuration is produced by the light which is received by the photodetector when the disk rotates. The light configuration received is translated into gray code. As a result, each position has its own unique bit configuration.

Typical construction for a rotary encoder is given as follows:

Rotary Encoders

Please note the following features:

  • Electrical connection to the right of the encoder body.
  • Encoder shaft that couples to the medical device.
  • Electrical specifications indicating the device is driven by a five (5) volt +/- 5% source.

Encoder Specifics

You can see from the above illustrated parts breakdown that a rotary encoder is quite technical in design.

SYSTEM ACCURACY:

System accuracy is critical, especially during surgery. Let’s look.

An encoder’s performance is typically stated as resolution, rather than accuracy of measurement. The encoder may be able to resolve movement into precise bits very accurately, but the accuracy of each bit is limited by the quality of the machine motion being monitored. For example, if there are deflections of machine elements under load, or if there is a drive screw with 0.1 inch of play, using a 1000 count-per-turn encoder with an output reading to 0.001 inch will not improve the 0.1 inch tolerance on the measurement. The encoder only reports position; it cannot improve on the basic accuracy of the shaft motion from which the position is sensed.  As you can see, the best encoders, hopefully those used in a surgical device, can deliver accuracy to 0.10 inch.  Remarkable accuracy for a robotic device and absolutely necessary.

CONCLUSIONS: 

TECHNOLOGY DELIVERS.  Ours lives are much better served with advancing technology and certainly technology applied to the medical profession. This is the reason engineers and technologists endure the rigor necessary to achieve talents that ultimately will be directed to solving problems and advancing technology you have seen from the post above.

As always, I welcome your comments.  bobjengr@comcast.net

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