Sunday, November 19, 2017

The Laws Of Perspective

I started with the course “Lectures On Digital Photography” by Marc Levoy. It is a course which was initially taught at Stanford for interested on-campus students, and then later at Google. Now all the lectures are available for free completely on Google Sites. Here’s the link: https://sites.google.com/site/marclevoylectures/home

Fifteen minutes into the first lecture, Mr. Levoy talks about one of the most important aspects of art- perspective. He talks about perspective in a scientific way. When you capture an image of a real object on a plane, be it as a painting, one of the earliest forms, or photography, which came much later, there are two important ways to look at it.



One was the natural perspective that Euclid explained in his book on Optics. The natural perspective discusses the distance between the eye and the object, and the angle the object subtends to the eye.

In simple terms, the natural perspective tells you that farther objects subtend smaller angles.

The other type is the linear perspective theory created by Filippo Brunelleschi. This basically tells you that closer objects are projected larger on a picture plane.


Using this simple mathematics as derived from the linear perspective theory, the approximate size of the projection on the plane as compared to the actual size of the object can be determined. In the above picture: y is the height of the projection; h is the height of the object; x is the distance of object from the eye; and z is the distance of the picture plane from the eye.

This was of key importance in the paintings during the Renaissance as the painters attempted to produce or showcase depth on a plane sheet. It was generally concluded from the linear perspective theory that all objects away from the painter must converge at a farther point.

So, how is this theory of perspective related to photography? Well, for photographers to choose an optimum focal length for the right aperture that would capture the scene, the way they envision, it is necessary that they have a general sense of perspective. It is not required, and is not possible, to do mathematics every time. But it is necessary to rather have a ‘feel’ of the right perspective that they need for a particular shot.

There is a tamil saying that translates into “Your hand doesn’t measure what your eye doesn’t”, which sums up the the topic of discussion here: perspective.

Tuesday, August 29, 2017

Why I Did Not Get My Hogwarts Letter


I was introduced to Harry Potter, and the world of wizards and witches when I was eleven. And ever since, I’ve always waited for my Hogwarts letter- most sincerely. People thought it was fiction but I knew it wasn’t just that. What I couldn’t understand though was why I did not receive my Hogwarts letter. Years on end, I peeped through the window to see if I could spot an owl approaching. No such luck.

Now, while pursuing B. Sc., LL. B., I finally found a convincingly probable answer to the question that has bothered me for the last seven years.

This semester we have a paper on Microbiology and Genetics. And, today, while winding up with the genetics topic, our professor showed us a video by National Human Genome Research Institute- Harry Potter and the Genetics of Wizarding.

Thanks to Prof. Eric P. Spana's wonderful lecture in the video, I got the reason why I might not be the one. For all those out there wondering why you didn’t get your letter- read this! The answer lies in your genes.

Let’s look at it this way: Why does Hermione Granger get the letter, but not us?
Brief answer: de novo mutations.

Let ‘W’ be the representation for the alleles of wizards/witches.
Let ‘M’ be the representation for the alleles of muggles.

To be a wizard/witch you need to have at least one dominant wizard allele ‘W’ or a recessive allele ‘ww’ gene.
Mr. and Mrs. Granger both are pure muggles(non-magical human beings).
So, both Mr. and Mrs. Granger are homozygous muggles: MM

Doing the Mendelian Cross:

Parents:                                   MM            x            MM
                                             (muggle)                  (muggle)
Gametes:                                  M                             M

Filial Generation 1:                                  MM            -----------------------> (Muggle)

So, how did Hermione, who was supposed to have only MM genes and be a muggle, become a witch?

De novo mutations are mutations that occur in an egg or sperm cell before fertilization or immediately after fertilization. ‘De novo’ literally means ‘of new’ in latin and refers to such new mutations.


De novo mutations may explain genetic disorders in which an affected child has a mutation in every cell in the body but the parents do not, and there is no family history of the disorder. Thus, even if there is no hereditary history whatsoever of magic use, the offspring can have a mutated gene affecting it, thus making the progeny magical.

Hence, Hermione got through to Hogwarts thanks to the mutation in her genes. This answers why she’s a mudblood.

But why not us too?

Well, de novo mutations occur at a frequency of ~77 per generation but only one of them occurs in a gene. So, analysing the past year students of Hogwarts we find just one person who is a mudblood in a given year. So for a wizarding or magical trait the frequency of de novo mutation in that gene is approximately 1 in 750,000 (considering the population of UK since Hogwarts is in UK).

That is a really slim chance. And, most probably we aren’t that 1 in 750,000 if we still haven’t got our letter.

That is why Hermione is a witch and we aren’t.

To know that our seven years of faith can be broken in one class of genetics with a little help from pure statistics is terrible. I can’t still stop waiting for the letter even after knowing the harsh truth.

And to conclude, and console myself for the rest of my life, I just figured a new argument:
Maybe, my letter was tied to Errol.

Sunday, April 30, 2017

The 39 Steps

Title: The 39 Steps

Author: John Buchan

Richard Hannay is bored and disgusted with the city life in London. Initially, it had been a sort of Arabian-Nights-come-true to live in the Old Country. But the pleasures of London had worn off well before a single month. As if in answer to his growing boredom, one day, he finds a man named Scudder in his house, who seeks refuge from dangerous enemies in Hannay’s place.

Scudder tells Hannay an elaborate tale of how he was being followed and why his followers want to kill him. Hannay, happy that something exciting was happening to him, agrees to shelter Scudder till he was safe to leave. While coming back home from outside, a few days after, he finds Scudder murdered brutally in his house. When everybody assumes that he is the murderer, Hannay sets off on a escape-adventure posing as many different people and exploring the mountains and moors of Scottish terrain and fleeing from two different sets of pursuers- one, the London Police for whom he is a murderer on the run, and two, the Black Stone(the murderers of Scudder) for whom he is a man who knows the deadly secret that Scudder knew. Along the way, he unravels Scudder’s real mission with the help of Scudder’s black notebook full of coded clues. With the timely aid of many innocents such as a milkman, a literary innkeeper, a radical candidate and a spectacled roadman, he continues with his mission to accomplish Scudder’s job.

I loved the part where he first meets the bald archaeologist and realizes that he is the dangerous man that Scudder narrated in his story. Hannay's shock at the realization and the desperate attempt to conceal his shock is most entertaining.

The 39 steps is a fast-paced book and is unputdownable. It is packed with action, adventure and thrill. The roller-coaster ride from Hannay’s monotonous life to one packed with suspense and mystery, is an amazing read!