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Philadelphia City, A Gigapixel image ( Please visit the zoomable version.) by electron
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Philadelphia City, A Gigapixel image ( Please visit the zoomable version.) by 


The above image is just a snapshot of the entire image. This is a “small” section of the entire image. The actual Image is 290 degrees X 65 degrees and spans across, across two states, Philadelphia, Pennsylvania and Camden,New Jersey. These two cities are divided by the Delaware river and are connected by the Benjamin Franklin bridge that runs over the river.

REMEMBER to ZOOM IN !!!

Prints? Contact me:
engineers.perspective@gmail.com

I have attempted to write a few words, about my effort into making this image. Breaking the gigapixel barrier brings happiness to me. Before going to a detailed description, let me conclude it first !

Conclusion:
I believe I need to talk to 50 cent ASAP. I saw him filling up his Lamborghini’s trunk with stacks of 100$ bills. May be if he can spare a fraction of it, I could buy some proper equipment.
:D

Shooting:
Our team went up the top (location not disclosed) and set up out equipment by 7:30 am. It was a VERY cold day with 15 mph winds. With increasing altitude, it made it even colder. Since the tripod head we used was all manual, the number of degrees of field of view the number of rows and columns had to be determined after we went up there. After 45 minutes of calculations the number of rows and columns were determined based on a 35 % overlap. This was not done precisely. Well, the result turned out okay. HA !

The markings on the tripod head were limited to 2.5 degrees ( 20 degrees / 8 divisions ). Since we were shooting at 324 mm, based on a 1.3crop sensor, I had suspected the angle of rotation to go below the unit measurement. Yes, it went below the unit measurement and so was forced to approximate half of the unit measurement. i.e. ~ 1.25, along the horizontal. The vertical rotation of the head was limited to one degree which actually made our job very easy. Some days ago, out of curiosity I broke dismantled/broke a video camera and salvaged a lens out of it. It was an excellent magnifying lens and I used to approximately measure the field of rotation to 1.25 degrees. It was important to preciesy measure it, not to get stitching errors at the end.

The photo shoot started. Based upon our previous attempts I calculated the shooting time to be around 7 hours. One of the team members had to help measure the angle, the 2nd team member had to tight the screw on the tripod mount and the third had to keep track of what sector were we shooting at. We decided to take some relaxing chairs with beer cup holders. I guess that was a mistake. It turned out to be a slow start. We also had focusing problems with no color transitions in the sky and no DOF sensed by the camera when staring at the open sky. Guess what, I had to throw the camera into manual focus and shoot half of the first row. It proved to be extremely time consuming with direct light hitting the lcd screen making it even worse using live view. Using the view finder was risky because of the height at which we had placed our camera. A slight amount of leaning on the camera would drop me along with my dear camera 17 floors down. I had two standby laptops a 500gb harddisk and a 2 TB hard disk. Enabled tethered shooting and started manually focusing every shot for the first row using the utility.

Well, It turned out that the grid I made to indicate the row and the column number based on the rotation along the horizontal axis turned out to be faulty. There was no time to discus about where it went wrong. The sun was rapidly changing its direction and major changes in shadows will definitely hinder post processing and stitching process. This was a huge task. We had to believe our intuition.

I had live view relayed to my laptop. Inbetween we ran out of battery. We expected to run out of battery so, had a replacement battery ready but did not expect, the tethered shooting to start with a new serial number for storing the photos. This lost all of my hopes to expect the grid number based on the table I made. Now, I was on my own. Missing one photo in the grid can be grave mistake as it will run the stitch.

Shooting the first row was the toughest with the clouds being featureless and the not so awesome lens we used, canon 75-300mm, did not help very much. The slow focusing and not having image stabilization were the major drawbacks. I hid myself and my laptop under my jacket, which shunned sunlight from directly falling on the monitor screen.

We finished the first row. We were already exhausted because of the sun, and the cold wind. It was time to switch duties. We finished half of the second row, when one of my team members had to leave for some reason. At this point, we had lost control over the grid of photos planned, the numbering pattern of the photos, and one team member. Looking through that magnifying glass and measuring 1.25 degrees approximately on a circular head was definitely a very hard task. It was my turn to measure the degrees and take photos. It demanded complete attention as I dint want to miss taking one photo along the horizontal or the vertical axis. Me and my second team member finished 3 rows ! At this point, I was feeling dizzy. I also was on sugar rush from the jelly filled donuts from dunkin. My second team member was also exhausted at this point. I could clearly see the exhaustion / a little bit frustration.

I went back to measuring degrees and handed him the remote shutter. I after every time I fixed the tripod on a new location I instructed him to take a photo. WE completed the photo shoot. YES our team did it.

541 photographs later, we were done. Since the grid position was partially based on intuition, I believe we may have taken a few more photos, JUST to be sure.

Thanks Chris and Tahir for helping me out.

Post processing:

I did a primary stitch. A lot of mistakes because of the changing shadows, the clouds and the sun. The sky was a disaster as the LDR correction blew it out of proportions. Bad news. The color rendition was just awful and there were many mistakes. I made a macro which converted all the 541 photos into smart objects with +2 EV steps. With 1623 images, the secondary stitch was a success with almost no color imperfections. With the addition of a 512 gb SSD drive and a 2 TB hard disk for scratch space, the output turned out to be free from pattern mismatches.Additionally distortion was corrected at a few possible places. MANY color anchors were introduced throughout the image, to correct the colors. Additionally, I selectively retouched about 90 images of the featureless sky to aid the stitching software understand where the clouds go. I have inspected the entire image on a 27 inch imac and it was a pleasure seeing almost no imperfections. Guess what, I also spotted PETER GRIFFIN.

At 300 dpi, this picture measures 495 inches long and 32 inches wide !

Tags

philadelphia, sandeepsarma josyula, gigapan, gigapixel image, skyline, philadelphia city, philadelphia high resolution, new jersey

Comments

  • DavidIori
    DavidIoriover 3 years ago

    Great effort well done

  • Thanks very much David.

    – electron

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