Elementary 2d rotation registration

Hopefully would prove useful for someone!

Representation of rotation is angle only; and optimisation is steepest decent. metric is the sum of squared difference metric. Shared purely for pedagogical purposes. Python code is horribly unoptimised.

import numpy, cv2
import scipy
from scipy import ndimage
import matplotlib
from matplotlib import pyplot
#def rotate_correct(fixed, moving, init_angle=0):
DATA_DIR = 'your_data_path_here';
FILE_NAME = 'fixed.png';
ROT_FILE_NAME = 'moving.png';
INIT_ANGLE = 0;
#
fixed = cv2.imread( DATA_DIR + FILE_NAME, cv2.IMREAD_GRAYSCALE);
moving = cv2.imread(DATA_DIR + ROT_FILE_NAME, cv2.IMREAD_GRAYSCALE);
#
fixed_im = numpy.float32(fixed);
moving_im = numpy.float32(moving);
registered_im = numpy.copy(moving_im);
#
NUM_ITER = 25;
STEP_SIZE = 0.00001;
BORDER = 70;
N = registered_im[BORDER:-BORDER, BORDER:-BORDER].shape[0]*registered_im[BORDER:-BORDER, BORDER:-BORDER].shape[1]
INIT_SSD_COST = registered_im[BORDER:-BORDER, BORDER:-BORDER] - fixed_im[BORDER:-BORDER, BORDER:-BORDER];

INIT_SSD_COST = numpy.sum(INIT_SSD_COST**2);
print('Initial_SSD: {0}'.format(INIT_SSD_COST))
estimated_angle = INIT_ANGLE;
D = numpy.gradient(registered_im);
D0 = D[0];
D1 = D[1];
term1 = numpy.zeros_like(fixed_im);
#
prevSSD = INIT_SSD_COST;
prev_angle = INIT_ANGLE;
for iter in range(NUM_ITER):
   
    term1[BORDER:-BORDER, BORDER:-BORDER] = registered_im[BORDER:-BORDER, BORDER:-BORDER] - fixed_im[BORDER:-BORDER, BORDER:-BORDER];
    update = 0.0;
    for x in range(BORDER,fixed_im.shape[1]-BORDER): #X direction
            for y in range(BORDER,fixed_im.shape[0]-BORDER): #Y Direction
#                 rotation_matrix = numpy.array( [ [numpy.cos(angle), -numpy.sin(angle)], [numpy.sin(angle), numpy.cos(angle)] ]);
                rotation_matrix_deriv = numpy.array( [ [-numpy.sin(estimated_angle), - numpy.cos(estimated_angle)], [numpy.cos(estimated_angle), -numpy.sin(estimated_angle)] ])
                x1 = x*rotation_matrix_deriv[0][0] + y*rotation_matrix_deriv[0][1];
                y1 = x*rotation_matrix_deriv[1][0] + y*rotation_matrix_deriv[1][1];
                term2 = D0[y,x]*x1 + D1[y,x]*y1;
                update = update + term1[y,x]*term2;
    update = STEP_SIZE*update/N;
    estimated_angle = estimated_angle - update;
    D0 = scipy.ndimage.rotate(D[0], estimated_angle*180.0/numpy.pi,reshape=False);
    D1 = scipy.ndimage.rotate(D[1], estimated_angle*180.0/numpy.pi,reshape=False);
    registered_im = scipy.ndimage.rotate(moving_im, estimated_angle*180.0/numpy.pi,reshape=False);
    SSD_COST = registered_im[BORDER:-BORDER, BORDER:-BORDER] - fixed_im[BORDER:-BORDER, BORDER:-BORDER];
    SSD_COST = numpy.sum(SSD_COST**2);
    currSSD = SSD_COST;
    if currSSD > prevSSD:
        estimated_angle = prev_angle;
        print('Minima reached. Exiting loop');
        break;
    else:
        prev_angle = estimated_angle;
        prevSSD = currSSD;
        print('Iter: {0}'.format(iter+1)),
        print('Step Update: {0} Estimated Angle: {1}'.format(update*180.0/numpy.pi, estimated_angle*180.0/numpy.pi)),

        print('SSD: {0}'.format(SSD_COST/INIT_SSD_COST))
    if iter == NUM_ITER - 1:
        print('Max iter reached. Exiting loop');
##
SSD_COST = registered_im[BORDER:-BORDER, BORDER:-BORDER] - fixed_im[BORDER:-BORDER, BORDER:-BORDER];
SSD_COST = numpy.sum(SSD_COST**2);
print('Final_SSD: {0}'.format(SSD_COST/INIT_SSD_COST))

print('Estimated_angle: {0}'.format(estimated_angle*180.0/numpy.pi))
##
DISPLAY = 0
BORDER  = 1;
if DISPLAY == True:
    #
    pyplot.subplot(131)
    pyplot.imshow(fixed_im[BORDER:-BORDER])
    pyplot.gray()
    pyplot.title('Before image difference')
    #
    pyplot.subplot(132)
    pyplot.imshow(moving_im[BORDER:-BORDER])
    pyplot.gray()
    pyplot.title('After difference ')
    #
    pyplot.subplot(133)
    pyplot.imshow(registered_im[BORDER:-BORDER])
    pyplot.title('Registered image')
    pyplot.gray()
    #
    pyplot.show()

Scary story about Monsanto in India

This is a very scary story. One can understand that there are various peculiar professions humans undertake so that they can make money. However, I cannot understand what kind of moneylust, lack of morals or ethics and shamelessness one must possess to work in such companies or the cola companies.

Vignettes:corporate life

We shall not take the names of the actual characters on whom the following short conversations are based, so as not to embarrass the organisations where the incidents or conversations actually happened. However, in order to give the reader, a summarisation of one aspect of the character or mental makeup of the the people involved; we shall use nicknames entirely.

Conversation Snippet 1:

Greenhorn: Dude, I saw you wagging your head consistently throughout the conversation you had in the cabin with the Manager. What gives? Have you been declared a Role Model?

The Wise Browser: Well, we know the Flight or Fight instinct in Living organisms.

Greenhorn: Yes, but are you going to launch into one of your analogies in mythology?

The Wise Browser: I apologise. 

Greenhorn: Alright, go on.

The Wise Browser: During conversations with Managers, one cannot fight. It is futile. Therefore, the other option is flight. Unfortunately, being enclosed in a glass cabin makes that impossible as well. But the body is crying to do something; then the involuntary response is what you observed.

Conversation Snippet 2:

Greenhorn: The new computers we ordered have arrived and the ITMS have delivered them to my desk. All of these assets are in my name. Why not I transfer these to your name, and you can allocate as per user request? Also I want to move all of those to your cabin.

The Leader(TL): Why do you want to do that? Just keep them. What do you have in your cupboard?

Greehorn: Books and papers.

TL: Well you can make some space. Look at it this way, you are more powerful now. You are the "owner" of all those machines. Haha..

Greenhorn: Haha.... Going by the same logic, the watchman of the warehouse is most powerful man in this centre then. haha...

TL: Well, lets not get flippant about this.

Conversation Snippet 3:
The Manager: You have used PCA for this project; PCA is 50 years old technology. We can have any Masters student do what you are doing; why would we have PhD people for this work?

Conversation Snippet 4:
The Browser: Sir, the Optimiser is getting scary.
Greehorn: Come on, dont whine as usual.
The Browser: No, it is true. I wrote C code for xxxx(some image processing algorithm). Now the Optimiser wants it in C++.
Greenhorn: First, for this deliverable, C or C++ makes no difference. Secondly, I think you have used some feature of C++; at least you have named some of the files as cpp. Maybe that is enough to convince the Optimiser...?
The Browser: Sir.... the Optimiser is asking , "where is class"? C++ must have class.

Few days later....
Greenhorn: Sir, did you re-write everything in pure C++ as demanded?
The Browser: Well, I wrote a class and put all the functions written earlier in this one class. The Optimiser is very happy..

Highly irritating song and fake lyrics

1. On the radio, a highly annoying song gets played all the time. The lyrics go 

"Tumne maari entry yaar" from movie Gunday. I think the music directors and the lyricists should be immediately executed for crimes against humanity.

2. There is one more irritating song; filled with poetic sounding urdu words. It is very clear to me that the writer has no sense of the language. The dunderhead came up with these words to sound cool or something. The moron is named Amithabh Bhattacharya and movie is Hasee to Phasee. I would not recommend outright execution, but deport the donkey to Pakistan. He can wax his Urdu there better. You may guess the song.

I feel better already!

Dell desktop pricing: scamming the customer

I was looking for a good desktop configuration from a well reputed seller. I checked out Dell India website. For the Dell Inspiron 3000 series, the model with 500GB disk costs, INR 37,290. The same configuration with upgraded hard disk costs 45,990/-. Dell must be very sure that there are lot of mugs in India. The price difference between 500GB & 1TB nowadays is barely 2000 or less. Even assuming that Dell will cream of some money, the difference of nearly 8000 is ridiculous. And then these desktop peddlers whine about falling PC market.

I had the misfortune to own an Inspiron laptop and now this.

Goodbye Dell

Minneapolis trip-part3

Eager readers who have been holding their breaths for the third installment of my travelogue to Minneapolis can slowly relax their thoracic muscles. 

Here is the link for the previous part. For those, who are not very keen on reading the earlier parts; here is a brief summarisation of the entire plot. In 2007, I had a paper accepted in a major conference in my domain; so much so that I took the trouble to apply for a visa to the United Corporations of America, also known as the USA or US. Possessing of a very dutiful and obliging nature, first the visa chappie put my visa on hold for further checking and secondly he told me that since my paper contained terms like "surveillance", he was duty bound to send it for this check. The information, he did not volunteer by himself; but told me curtly on being asked by me, the reason for the extra checkup. I would like to think that he was startled on being interrogated in turn; as low lives from 3rd world countries do not usually ask but accept these as their the fruits of their karma. He was also kind enough to inform me that since the conference was approximately 35 or so days off; he had some hope that my background checking would be done within that time. Otherwise, it was chop chop. Be as it may; i thought that the money was not completely wasted. However, days passed and I got no information from them. I thought that the money was wasted after all. But about 3-4 days before the conference began, I got a call or an email; i forget now saying that my visa was granted and i had to go to the embassy and submit my passport for stamping. I was annoyed, because the time was really gone. This was a Friday, next 2 days were holidays. Monday would be the day to collect the visa, and on the same night I would have to catch a plane. Logistical nightmare. I had no prior experience of phoren travel; but i was aware of thousands of papers or formalities. I did not have much money either. Anyway all these difficulties and my great reluctance to rush off to places unknown at short notices, were somehow surmounted by some active support by family and I was duly seen off at the airport by kith and kin.

In the rushing around for tickets, visa stamping, clothes packing and so on; I had no time to book an accommodation in Minneapolis. The conference organisers had made some arrangements at the University of Minnesota campus; but the cutoff date was long past. I had made some searches for cheap stay in Minneapolis, and had saved the link for the Minneapolis youth hostel. We never know when some little action of ours can save our skin. At the Heathrow terminal, I paid a lot of money and luckily was able to see the Hound from Hell online. I pinged him and to his everlasting credit, he quickly booked a room at the Minneapolis youth hostel from the link I had saved. However, my money ran out and I was left with no address or phone number of the hostel; or not even the knowledge of if the booking had gone through. OK, I am not likely to win Nobel prize; I know that. I landed in Mineeapolis at 9PM local time. As I said, people vanished in thin air. An India, scampered away from me; seeing that I had nowhere to stay.

Now the current stuff of this blog post

I pondered. What do I do? I tried looking at the telephone directories in hope of finding the number from there but I could not find any. I could not believe that an airport could be so desolate. I thought that it might not be a good idea to dawdle around; might get caught for  interrogation and what not. I did have the address of the university accommodation with me; i thought i would try my luck there. Surely, they could not turn away an international student at 9PM. Next day, I would find something or the other. OK, I go to travel stand, and see lots of taxis. OK, again I admit that I am not a very bright spark; I should have taken a metro or bus for cheaper travel; but in the rush of leaving from India, i never did those homework. I went to the booth; showed the address and the lady there shook her head. Never knew the place. Not her mistake completely; I had taken the name of the lane inside the "campus". One or two taxi drivers were tried to help me but they had no clue either. One driver was more persistent than the other; and he dug out some more information from the lady based on what I told him(university accommodation/hostel etc.). We started off. I had no clue where the hostel was and was trusting the driver. In India, it is expected that the driver will cheat you, either by rigging the meter, or going by the most circuitous rout and other tricks of the trade. I had mentally assured myself that I would be ripped off, and would tell the driver when I reached the end of my money to let me off. I was completely wrong.  After sometime, the driver started asking questions, from where I was, why was i in america. He heard I was a student and said he too was trying to study and do something. He was from Somalia, so he said. All very matey but then I saw the meter at 30$ or so, and we were still travelling. I told him at a signal that I was not cash rich, and he could let me down if he thought we were close enough. It was more than 11PM. He was also having trouble getting to the exact location; he was roughly in the correct area. He told me not to worry and he would give me a discount; being a student himself he knew we were all hardpressed for money. Soon enough, we did reach the hostel; and as promised he said that he would have to take whatever was there on the meter. The discount was 3 or 5 $ which he said he would have normally charged he had to pay the airport chappies for parking his vehicle there. I told him that, he should take all his money, meter and this extra surcharge, but I would not be able to give anything as tips, and beseeched him not to mind. He was ok with the deal. I got down my luggage and he drove off, receiving my thanks and money. Now, with luggage i entered the hostel/dorm, and said I was conference attendee and would there be a room please. I had not made a booking but if there was a room, single or shared, i would be grateful. The counter was manned by a white chappie and a chinese girl. The WC said no room. I then tried the name of the co-author who had reached earlier, and could I speak with him or get some information about him? They checked the visitor list and obviously no luck. I got a bit amxious. I requested that any accommodation is fine; the reason for this mess was that I got granted the visa the day i had to leave. No luck. OK. If it is full, noone can do anything; not even for outstation student travellers with no friends or family. OK. I then requested the use of the computer system; I wanted to see my email and get the address of the youth hostel in case the booking had been done there. The WC said no; computer use only for guests. The CG looked uneasy. I got annoyed and told that this mess was because the visa was issued late and not fully due to my stupidity. No dice. Then, I told him that I would give my password and login for GMail and he could type, check the email and give me the address. No, said the WC. CG looked more uneasy, and the WC moved aside a bit for checking on on something. The CG took the opportunity to slide the keyboard a bit, and turn the monitor to my side and said in a low voice to type. I did not; i did not want to get the CG in trouble, and there was no guarantee that the WC would not get annoyed and call police or something. I ignored the CG; I hope she understood that I was not being rude to her. I appreciate her today also.

Then in my nastiest voice, I asked if i could look at a telephone directory at least. That was given; and i searched for the hostel. I only knew it began with Minneapolis. I did not know the full name. After one or two false tries; I got the number and spoke to the "manager". He confirmed my booking, and told me I was late. I said OK. Now, I did have the address and did not know how to go there. I asked the manager, and he said to take a cab. I asked how much would it cost; and he said about 10$, he also said he knew a cab company; and i said alright. Send it. I do not remember if I thanked thr WC for the use of the phone at least; i must have. I also do not recall if i thanked the CG. I do thank her now and again.

The driver was a white chap(I am not hung up on the colour of the skin, I am just narrating). The ride was short and it came to 7.5$. The driver put the 10$ note in his pocket and said thanks. I got down and retrieved my own luggage. I had shelter.

Prof Casselles

Recently, I read about the demise of Prof. Vicent Casselles. It is very sad. I have of course skimmed through his papers; skimmed because his works are generally advanced than my poor knowledge will permit. In the early days of my phd work, while trying to understand geometric active contour models, I was going back reference after reference. I finally came across 3 papers or so of Prof. Vicent. The papers were quite old and I was not able to locate them online, and so emailed him, requesting a PDF. To my pleasant surprise, after a few days, I got a postal package not only containing those papers but a few others besides on the same topic, and a hand written note wishing the best. I have always felt thankful to him for taking this trouble.

huawei g300 failure and lesson: avoid like plague

i bought a huawei g300 about 5 months back; after going through a lot of reviews. I was not a smartphone fan; in fact I am more than happy with Nokia X2-02 and Samsung E2232.

I think it was bad karma which made me buy this stupid smartphone thingy, and that too from Huawei. The phone was a bit slow; expected because of limited memory. Apart from that, and very poor FM radio reception, the phone was ok. One morning, some day last week I woke to see the phone blanked out. I thought that maybe wifi had been left on, and the battery had drained out. I put the phone on charge, and tried to switch it on. No response from the phone. I let it charge for some more time, thinking that the phone had drained off completely. After sometime, the battery showed 10% in the battery icon itself; the phone was still not on. It was unusual; because usually by that duration battery is usually 30%. I removed the charger, pulled out the battery and put it back in and restarted. This time it went to 40%, I was satisfied and pressed the power button on top. The phone started; joy. But not so fast; it got stuck at the huawei logo. Internally, I felt that this was not good and something bad was happening. After multiple restarts, battery removals, the phone managed to go to the homescreen. But, no signal! It did not recognise any carrier. After lot of searches using Google; I saw that people in UK had suffered from the same problem; but some of them had the problem after the phone was unlocked from a carrier. In India, there is no such problem of tying to a carrier. So i thought that this was not my problem and tried to look for other reasons. At some point I did a complete wipe/factory reset; and lost all my apps as well. Some people had problems with "Airplane mode on"; i also had that icon creeping up occasionally. While the airplane icon was present; the great thing was that if I went to settings, the mode would be off.

After multplile and increasingly frustrating reboots, SIM changes; I saw that my IMEI number was unknown. It is baaaaad news. I had not rooted; not installed dodgy apps but my phone just dies on me! I sent an email outlining my frustration to the Huawei Indian website day before yesterday. Naturally, I got no response. Dodgy chinese company employing indians who on an average have no sense of pride in their work and have no self esteem being enslaved for millenia and now being low cost code monkeys; I do not expect anything from them.

I will have to travel 15 km to see if the phone can be salvaged by the service centre. Since there is warranty; I hope not to be charged any money. But I would rather junk the phone than pay a rupee to this junk company.