3-D scanning with water

source: this website

A global team of computer scientists and engineers have developed an innovative technique for 3D shape reconstruction. This new approach to 3D shape acquisition is based on the well-known fluid displacement discovery by Archimedes and turns modeling surface reconstruction into a volumetric problem. Most notably, their method accurately reconstructs even hidden parts of an object that typical 3D laser scanners are not able to capture.

3D scannerTraditional 3D shape acquisition or reconstruction methods are based on optical devices, most commonly, laser scanners and cameras that successfully sample the visible shape surface. But this common approach tends to be noisy and incomplete. Most devices can only scan what is visible to them but hidden parts of an object remain inaccessible to the scanner’s line of sight. For instance, a typical laser scanner cannot accurately capture the belly or underside of an elephant statue, which is hidden from its line of sight.

The team’s dip transform to reconstruct complex 3D shapes utilizes liquid, computing the volume of a 3D object versus its surface. By following this method, a more complete acquisition of an object, including hidden details, can be reconstructed in 3D. Liquid has no line of sight; it can penetrate cavities and hidden parts, and it treats transparent and glossy materials identically to opaque materials, thus bypassing the visibility and optical limitations of optical and laser-based scanning devices.

water 3D scanningThe research, “Dip Transform for 3D Shape Reconstruction“, is authored by a team from Tel-Aviv University, Shandong University, Ben-Gurion University and University of British Columbia. They implemented a low-cost 3D dipping apparatus: objects in the water tank were dipped via a robotic arm. By dipping an object in the liquid along an axis, they were able to measure the displacement of the liquid volume and form that into a series of thin volume slices of the shape. By repeatedly dipping the object in the water at various angles, the researchers were able to capture the geometry of the given object, including the parts that would have normally been hidden by a laser or optical 3D scanner.

The team’s dip transform technique is related to computed tomography, an imaging method that uses optical systems for accurate scanning or to produce detailed pictures. However, the challenge with this more traditional method is that tomography-based devices are bulky and expensive and can only be used in a safe, customized environment. The team’s approach is both safe and inexpensive, and a much more appealing alternative for generating a complete shape at a low-computational cost using an innovative data collection method.

In the study, they demonstrated the new technique on 3D shapes with a range of complexity, including a hand balled up into a fist, a mother-child hugging and a DNA double helix. Their results show that the dip reconstructions are nearly as accurate as the original 3D model, paving the way to a new world of non-optical 3D shape acquisition techniques.

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what’s up, Handle?

Handle

Handle is a research robot that stands 6.5 ft tall (about 2 meters), travels at 9 mph (about 14.5 kmh) and jumps 4​ ​feet vertically (about 1.2 m). ​It uses electric power to operate both electric and hydraulic actuators, with a range of about 15 miles (about 24 km) on one battery charge. ​​​Handle uses many of the same dynamics, balance and mobile manipulation principles​ found in the quadruped and biped robots built by Boston Dynamics, but with only about 10 actuated joints, it is significantly less complex. Wheels are efficient on flat surfaces while legs can go almost anywhere: by combining wheels and legs Handle can have the best of both worlds.

Faster, noninvasive method to determine the severity of a heart failure

source: this website

tueMethods currently employed to determine the severity of a heart failure are very limited. Researchers at Eindhoven University of Technology and the Catharina Hospital in Eindhoven have therefore developed a method that is very quick, non-invasive, cost-effective and can be performed at the hospital bedside. Moreover, this method appears to have a predictive value for whether or not a double pacemaker will be successful. Researchers Ingeborg Herold and Salvatore Saporito received their doctorates last month for their study.

Heart failure – when the heart is no longer able to pump enough blood through the body – is a very common problem. To get the right treatment, it is important to measure how well the heart is still able to do its job. There are currently various methods for doing this, but all have their limitations. Sensors often need to be placed in the large arteries, via the shoulder or neck, and that is quite an invasive procedure. MRI is a possibility, but not for patients that are seriously ill. Patients that are short of breath nearly always undergo blood analysis, a method that examines the concentration of a particular protein in the blood and provides a very good, patient-friendly indicator, but it takes several hours before the outcome is known.

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The Eindhoven researchers have developed a patient-friendly method that uses an echo scanner, which is known mainly for echoes performed during pregnancy, to determine the severity of heart failure. To do this, they measure the time it takes for the blood to travel from the heart’s right ventricle through the lungs to the left ventricle, which is responsible for pumping oxygenated blood through the body. In order to measure this pulmonary transit time (PTT), they inject harmless microbubbles that can be seen clearly by the echo scanner. They then look at the heart and see how long it takes for the bubbles to get from the right to the left ventricle.

animatedpacemakerIt may seem simple enough but there was a significant scientific challenge in calculating an unequivocal PTT for the observed microbubbles that get dispersed in the blood flow. But once that had been solved, they compared the transit time with a number of existing indicators, developing a similar method on the basis of MRI. Comparisons revealed that the PTT measured with the echo scanner provides an excellent indicator for the severity of a heart failure. A healthy heart pumps the blood quickly through the lungs. The longer the PTT, the less well the heart performs. They examined subjects whose heart muscle no longer contracted well, which is the most common type of heart failure. Before the method can be used, there is still work to be done. For example, if it is to be both practical and fast, the analysis will have to be automated.

Ingeborg Herold gained her doctorate on Thursday 17 November for her thesis “Assessment of cardiopulmonary function by contrast enhanced echocardiography” while Salvatore Saporito received his PhD the same day for his thesis “Cardiovascular MRI quantifications in heart failure“.

Crutches: some hints

source: this website

For lower-limb injuries (broken leg, broken ankle, sprained ankle, knee injuries), as well as after lower limb surgery, crutches can be used to decrease discomfort, reduce recovery time, and assist walking. Often, when a cast is put on the leg or on the foot, or in the case of weak muscles or gait instability, the use of crutches might become necessary for a period of time. Crutches may also be used by amputees, and people with other disabilities that make walking difficult.

A crutch must do two things: reduce the body weight load on the injured limb and broaden the user’s support base to improve their balance and stability. The support also should assist upright movement and transmit sensory cues through the hands. The main benefit provided by crutches is the ability to keep an upright posture and, therefore, to be able to maneuver in places that could not be reached, for instance, with a wheelchair. Regaining upright body movement aids circulation, assists kidney and lung functions, and helps prevent calcium loss from the bones.

Crutches shift the force of upright movement from the lower limbs to the upper body. The user must have sufficient arm strength, balance, and coordination to use them effectively. There are several basic types of crutches:

  • c6b9729b3b1feff84fc553551deff3cdaxillary / underarm crutch – the most common type, can be adjusted easily to the user’s overall height and hand height;
  • forearm / Lofstrand / elbow crutch – allows 15°-30° elbow flexion-extension movements, letting the user bear a greater weight;
  • platform / triceps crutch – conceived to avoid bony contact on the arm, though providing stability;
  • strutter crutch – provides larger crutch tips that remain flat on the floor and allow for improved weight distribution and more even walking gait;
  • leg support crutch – like a knee scooter, the affected leg is strapped into a support frame on wheels. This type of crutch is particularly useful for below-the-knee injuries or postoperatively after surgeries that affect one leg only.

Walking with crutches is not easy. Studies have shown that the wrist joints receives from 1 to more than 3 times the body weight during the swing phase of walking with crutches, a load that the upper body was not designed to sustain. Crutch comfort can become an issue, as the user’s body acclimates to their use.

SpotMini, nice to meet you

SpotMini is a new smaller version of the Spot robot, weighing 55 lbs dripping wet (65 lbs if you include its arm). SpotMini is all-electric (no hydraulics) and runs for about 90 minutes on a charge, depending on what it is doing.

SpotMini is one of the quietest robots that Boston Dynamics have ever built. It has a variety of sensors, including depth cameras, a solid state gyro (IMU) and proprioception sensors in the limbs. These sensors help with navigation and mobile manipulation. SpotMini performs some tasks autonomously, but often uses a human for high-level guidance. For more information about SpotMini, visit www.BostonDynamics.com