Lens Stereoscopy

3D viewing is widely used in cinemas today. Technologies such as, Active Shutter, Polarization and Interference filter method are used for 3D projection. In all these methods the basic idea is to provide two different images to each eye like we naturally perceive the world. Then the brain does the rest of the work and combines those images to perceive depth. Although 3D vision is most common in movies at present, in the past it was used in Remote Sensing for military purposes. The instrument used for this purpose is the Stereoscope.

the stereoscope with an image

The Stereoscope consists of two lenses resting on a stand that focus on the two separate images of the stereoscopic image sheet. When looking through the two lenses, each eye sees a slightly different image that is meant for that eye and this results in the perception of depth - the image appears 3 dimensional. This is very useful in analyzing aerial photographs because it allows viewing the ground terrain in 3D.

test image for stereoscopic vision

Shown above is a test image that is used to check stereoscopic vision. The relative heights at which the symbols appear to be seen can be checked against the actual order of heights which are provided overleaf.

Stereoscope with a test image

While in modern remote sensing, stereoscopes have been replaced by more advanced computerized equipment that not only provide 3D views but also help manipulate images in 3D, the stereoscope helps understand the basics of stereoscopic vision. Lens Stereoscopy can also be considered as the foundation of all modern stereoscopic equipment.

Stepping into Field Geology

While Geology is a field of study that takes place both outdoors in the field and indoors in laboratories, Field Geology is a primary constituent of Geology. Most of the activities that are involved in Geology like sample collecting, mapping and recording takes place in the field. When moving into field geology for the first time, several important points need to be considered.

The first thing that needs to be considered is, Safety in the field. Mostly this means to be aware and protect one's self against threats from nature and wild animals. For this purpose a thorough knowledge about the surroundings, proper equipment and first aid facilities are essential. In the case of snake bites it is useful to know the closest hospital or medical center equipped with anti-venom serums. In addition to the above, proper usage of tools like the hammer and chisel will reduce the likelihood of an accident.

Once the safety is taken care of, the right tools and equipment related to field work must be made available. The common tools used in field geology are, Geological Compass(Brunton pocket transit or Silva compass), Hand lens(10X), Hammer and chisel, waterproof field book, mineral testing kit and sample bags. In addition to these basic tools, additional tools such as camera, GPS, binoculars  gold pans, metal detectors and Geiger  counters may be used for specific requirements.

The Geological Compass is arguably the most useful tool at the disposal at the Geologist or Engineer. In addition to the obvious purpose of locating the direction of north and calculating the bearing, a geological compass has the following functions.
- Finding the dip and Strike of geological features such  as foliation, joints bedding planes etc.
- Measuring slope angles
- approximating heights of objects
- a level
When using a compass, it is essential to keep away from vehicles, power lines and any other magnetized objects. This means that the Hammer and chisel also needs to be kept aside when using the compass. With the emergence of smartphones with magnetic sensors and accelorometers, applications that perform similar to a geological compass have been developed. One such application that can be used for traversing, calculating Dip and Strike along with a host of other useful functions is, Rocklogger which is available for the Android mobile platform.

Another important aspect of Field Geology is Sample Collection. When collecting rock samples, an approximate sample size of 3"x3"x3" or 4"x4"x4" is preferred. Weathered rock samples are generally avoided unless it is a specific requirement. Once collected, sharp edges should be trimmed off before bagging the sample to avoid tearing the bag. Cloth bags made out of a cotton fabric are usually used for this purpose. Samples should also be numbered systematically. While there is no hard and fast rule for this, a meaningful numbering system incorporating information such as collection year, area, and collectors initials is used to avoid confusion.

Field photography is also a requirement in certain cases. When taking a picture always a scale should be used. For small objects, a pen or another small object with a known size must be in the picture. In the case of photographing macro structures, wetting the surface of the rock helps to bring out the fine details on the surface. Care should be taken to avoid shadows to fall on a part of the rock when  photographing because it could lead to misinterpretation.

Brunton Compass - image from wikipedia

An Introduction to Remote Sensing

Remote Sensing, like the name implies, means observing and gathering information of an object from afar. In this sense we humans perform remote sensing all the time with our eyes and ears, where eyes and ears are our remote sensing equipment. However when moving away from the basics and expanding the scope of observation, many factors become involved and remote sensing becomes a broad and detailed area of study. Incorporating all these ideas, a general definition for remote sensing can be given as,

"The art and science of obtaining information about an object without being in direct contact with the object"

Remote sensing is extensively used in observing the earth and the environment for various purposes. The most common application of remote sensing is done in mine development, disaster mitigation and large scale environmental studies. Depending on the application, the sensors and the type of radiation used, the method of recording and processing and the analysis of the data will differ.

The major components in remote sensing are,
- an energy source for illumination :- usually the sun or an artificial source of radiation.
- medium of travel for energy :- the atmosphere.
- sensor :- orbits in a satellite eg. Landsat, Quickbird
- receiver on earth :- gathers the data transmitted from the satellite.
- equipment for interpretation and analysis of data :- remote sensing software.

All remote sensing systems have four types of resolution. They are,
- Spatial resolution :- refers to the pixel resolution of the image produced.
- Spectral resolution :- refers to the range of EM radiation that can be detected. A broader range increases the scope of analysis.
- Temporal resolution :- refers to the orbital period of the satellite carrying the sensor. Faster the period, higher the resolution.
- Radiometric resolution :- refers to the differences of the intensity of radiation that can be distinguished by the sensor. Given as a bit range. A higher bit range can distinguish smaller variations.

Once all the above details are decided according to the application, remote sensing is performed. Then a "reflectance pattern" is produced from the gathered data. By comparing these patterns with the spectral signatures of known objects, the type and extent of the sensed objects on the earth can be inferred. In addition to various applications on earth, remote sensing is also used in other planets to gather data about surface conditions etc without landing on the planet.

Remote sensing in Mars. image form wikipedia

 

A Diamond is Forever

Gemstones have been objects of desire since ancient times and are commonly seen as symbols of wealth and prosperity. The field of Gemmology aims to identify, classify and add value to gem material. Of all the gemstones identified, the diamond holds a special place due to various reasons. While already being the most sought after gem stone, efforts companies like De Beers have increased the value of diamonds even more. An example is, the De Beers advertising slogan "A Diamond is Forever". This slogan increased diamond sales to such an extent that a diamond was a part of almost every engagement ring. It was coined by Frances Gerety and is regarded as the best advertising slogan of the 20th century.

The value of a gemstone usually depends on its beauty, rarity and hardness. Although these are very vague terms and beauty is not quantifiable, the factors that contribute to beauty are colour and clarity. In gemstones like aquamarine, value generally increases with colour intensity. In blue saphire, the value is highest at a particular colour, termed the "optimum colour". Clear gemstones without any intrusions or impurities are usually cut so that they are faceted. translucent, opaque or sometimes clear stones with intrusions are cut with a convex top and are called "cabochons". Even opaque stones can be valued highly due to properties such as Chatoyancy (cat's eye) eg- Chrysoberyl. and Asterism eg. Star saphire. Among so many varieties of stones the clear, faceted diamond is the most sought after.

The other factor that contributes to the value of a gemstone is its rarity. while gemstones are naturally rare, the demand for it creates an increase in value. However in some cases the rarity can be increased by the producers or traders of gemstones by stockpiling and controlling the release of gemstones to the market, like what De Beers did when they held the monopoly in the diamond business at a certain period of time. These practices however, rarely take place today. Hardness is the other key property of a gem quality material. A high hardness value means high durability and therefore it stands the test of time. Whether it's the case of beauty, rarity or hardness, the diamond clearly stands on top.

image from : wikipedia

The Evolution of Human Resource Management

Human Resource Management is a diverse field that aims to bring out the best in employees in order to accomplish organizational goals while facilitating personal development of the employees as well. Most organizations in various industries have embraced Human Resource Management as a core function of the organization and are reaping its benefits. Although field of HRM is a comparatively recent development, its roots can be traced back to the pre-industrial era.

During the pre-industrial era the closest thing to the employer-employee relationships was the relationship between landowners and slaves. Here the landowner had the slave/s at his disposal and had complete power over him/them. Although it is a violation of human rights according to present standards, slavery was commonplace until it was abolished in many parts of the world.

The industrial revolution resulted in the creation of the factory system. Now the relationship shifted to, owners of factories and workers. It was during this time that The theory of Scientific Management was put forward by Frederick Winslow Taylor. In Scientific management, ways in which efficiency of a factory could be increased were discussed. Although some of these methods included training of employees and selecting the employees with the right skills, even this was a long way from the modern HRM approach because among the basic assumptions in Scientific Management were the notions that, man is an "economic animal" and that money was the primary factor in motivating employees.

An improvement of Scientific Management came in the form of the "the Modern Management Theory" by Henry Fayol. In this theory fair treatment of all employees is argued while giving more consideration to the proper treatment of employees. In this theory Fayol also claims that people can be motivated by more than just money. This was a major milestone in the road towards modern Human Resource Management because employee motivation and fair treatment of employees are key areas in modern HRM.

After the modern management theory and its successors came into place, the Human relations movement began taking shape. With this came the labour movement and the state got involved in the protection of employee rights. This resulted in a tripartite relationship between the state, employer and employee that aims to bring stability to the industry while working for the benefit of all three parties.

Now with the state involved and legal matters involved in the field of employment, organizations felt the need of "Personnel Management". personnel management, as the name implies is meant to manage employees in an organization. It focused mainly on getting the right employees for the organization to perform a job while also fulfilling the legal requirements and ensuring that employee rights are not violated.

While Personnel Management was effective in the short term, it did not produce significant improvements for an organization in the long run. Thus organizations opted for another option that would be fruitful in the long term. This was the beginning of Human Resources Management. Like the name says, HRM considers employees as a "resource" to be developed. Therefore, a key area in HRM is providing development and career advancement opportunities to employees. In other words HRM aims not to provide just a job, but to provide a career to their employees. Human Resource Management aims to attain organizational objectives by simultaneously developing its employees, and this approach has been proven to be successful.