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Quorten Blog 1

First blog for all Quorten's blog-like writings

More information on IR and UV pass/cut filters

quorten

2016-12-24

Categories: raspberry-pi   pentax-k-1-camera  
Tags: raspberry-pi   pentax-k-1-camera  

Okay, continue to search for filters. This time, IR pass. Guess what, I was able to find the a good IR pass filter from the same website.

20161223/http://www.pmoptics.com/filters.html
20161223/http://www.pmoptics.com/ir_filters.html

Okay, but what about UV pass filters? Judging from the text of the website above, I should just search for “UV filters,” apparently.

Oh wait, I should search for “UV pass filters.” Yeah, I think that should provide for broader results in my specific category of search.

20161223/https://en.wikipedia.org/wiki/UV_filters

Oh, but interesting. I’ve learned that sunscreens are a new class of environmental pollutants. One of the main problems is that wastewater treatment facilities are (for the most part) not capable of filtering out sunscreens from waste water.

20161223/http://www.globalspec.com/industrial-directory/uv_pass_filters

Those filters are too big. And, despite the IEEE logo, I think the selection of products is too limited.

20161223/http://www.naturfotograf.com/UV_IR_rev04.html

Read on →

On computer user growth, and Raspberry Pi's competitors

quorten

2016-12-23

Categories: raspberry-pi  
Tags: raspberry-pi  

Oh yeah, and notes on the computer user growth. Nowadays, the largest computer user growth is in smartphones. But, don’t be fooled. Obviously, you can’t do as much with a smartphone as you can with a laptop or desktop PC. So let’s put it this way. We have reached a certain inertial point in the number of people who use desktop and laptop computers. We could say that they have reached the limits of human capabilities, and humans are not capable of doing any more with such machines. BUT, note that people still must program computers, and for that, one needs some sort of convenient development environment, hence desktop and laptop computers. And, computation inside of data centers is scaling up significantly. So there you go. Back-end servers where they cannot be seen or heard, there mainly to fuel the demands of smartphones that cannot compute on their own.

Anyways, here we take a look at some of Raspberry Pi’s competitors.

20161222/https://getchip.com/
20161222/https://en.wikipedia.org/wiki/CHIP_%28computer%29
20161222/https://en.wikipedia.org/wiki/Comparison_of_single-board_computers
20161222/https://en.wikipedia.org/wiki/Banana_Pi
20161222/http://www.pcworld.com/article/3138886/computers/the-orange-pi-zero-single-board-computer-ships-for-699.html

Finally found ideal filter for Raspberry Pi NoIR camera

quorten

2016-12-23

Categories: raspberry-pi  
Tags: raspberry-pi  

Further searching on Raspberry Pi NoIR filters. If DuckDuckGo doesn’t give me good results, why don’t I try Google?

20161222/Google raspberry pi noir camera filters

Indeed, I’m getting some actual results now!

20161222/https://tinkererblog.wordpress.com/2016/03/08/raspberry-pi-noir-with-ir-cut-switch/

Only $3! Much better than my previous $15 find!

20161222/https://www.aliexpress.com/item/CCTV-IP-module-dedicated-IR-CUT/32323006210.html
20161222/https://www.raspberrypi.org/forums/viewtopic.php?f=37&t=96997&p=673996#p673996

UPDATE 2019-11-28: The AliExpress link is no longer valid, the manufacturer discontinued the item.

Oh, so this is the story behind the included blue gel filter that comes with the Raspberry Pi NoIR camera.

20161222/https://publiclab.org/notes/warren/10-29-2013/raspberry-pi-infrared-camera-ships-with-public-lab-s-infragram-filter

Here is an instructable that recommends tweaking the focus on the Raspberry Pi Camera by breaking the glue. Also, it comments that the IR illuminators are probably designed for security cameras, thus taking 12 V rather than 5 V.

Read on →

Raspberry Pi remote monitoring, Raspberry Pi Zero

quorten

2016-12-22

Categories: raspberry-pi  
Tags: raspberry-pi  

20161221/https://lifehacker.com/remotely-monitor-a-raspberry-pi-to-see-whats-running-an-1790194857
20161221/https://github.com/initialstate/pi-process-dashboard/wiki

^ Pictures a Raspberry Pi Zero ($5), now that they’re starting to become more available. Partially due to the fact that competitors are kicking in to help reduce the demand for Raspberry Pi Zero.

20161221/http://lifehacker.com/create-a-multiple-camera-motion-sensor-controlled-surv-1753841433
20161221/http://www.pyimagesearch.com/2016/01/18/multiple-cameras-with-the-raspberry-pi-and-opencv/

^ Well, that’s a little bit dated, as it makes no mention of just buying multiple Raspberry Pi Zeros and Raspberry Pi cameras, which is now a viable option. Yeah, with the older Raspberry Pi modules, you’d definitely be concerned about the cost of all those Raspberry Pis.

OR, alternatively, you can use print statements in your program to print debugging information to the log files. And that’s something that works adequately with modern C programming environments.

The perils of working with film

quorten

2016-12-21

Categories: pentax-k-1-camera  
Tags: pentax-k-1-camera  

The perils of working with film. Yeah, sometimes when you take the pictures, they might not turn out. But, what’s most shocking. There were some times when Dad took the film to target to get it developed, and when he got it back, none of the pictures turned out due to poor development. “Hey, you did an awful job developing my film!” “Too bad, already developed.” “I demand a refund.” [Sorry, we’re mafia.]

So, beyond the other inconveniences of handling film, that was another issue at hand.

More news and methods of 3D scanning

quorten

2016-12-20

Categories: 3d-scanning   3d-scanner  
Tags: 3d-scanning   3d-scanner  

What? News of a possible 3D sensor? Sort of. Here’s the deal.

20161219/https://youtu.be/0QNiZfSsPc0
20161219/https://atap.google.com/soli/

The video touts the radar as “very high positional accuracy,” which is more vague than deserved, so here is an accurate number computed from the specification on the Project Soli website. 60 GHz electromagnetic radiation has a 5 mm wavelength, so being optimistic about sub-wavelength detail recovery algorithms, “very high positional accuracy” is measuring details within 1 mm of accuracy.

Also note that the portion of the video displaying the reflected waves off of the hand to the sensor was drawn to spatial scale, given the wavelength of the radar signal. Time scale, of course, was greatly exaggerated.

Before you go too far “imagining the possibilities,” you still have to remember the limits.

This is in fact “microwave” radiation.

20161219/https://en.wikipedia.org/wiki/Microwave

Read on →

More reviews and info on Pentax K-1, and lots other info on photography

quorten

2016-12-17

Categories: pentax-k-1-camera  
Tags: pentax-k-1-camera  

Okay, so now you’re calling even more into question reviews on the Pentax K-1. Now, you’re asking, what about the professional review articles? Well, I’m going to look into those.

20161216/https://www.dpreview.com/reviews/pentax-k-1
20161216/https://www.cnet.com/products/pentax-k-1-review/
20161216/http://imaging-resource.com/PRODS/pentax-k1/pentax-k1A.HTM
20161216/http://imaging-resource.com/PRODS/pentax-k1/pentax-k1TECH.HTM
20161216/http://imaging-resource.com/PRODS/pentax-k1/pentax-k1-field-test.htm

  • Let’s look at some of the impressive showcases of how high the resolution of the Pentax K-1 goes.

    20161216/http://216.18.212.226/PRODS/pentax-k1/FULLRES/YIMGP1253.JPG
    20161216/http://216.18.212.226/PRODS/pentax-k1/FULLRES/YIMGP1254-psr-no-mcomp.JPG

    Indeed, I must admit, those are pretty good pictures. Oh yeah, and I really wonder about this. Well, concede. Do you really need high resolution for video? Oh sure, it always looks nicer with high resolution, it’s just that my concern is that, well, the purpose of high resolution still photographs is to be able to look around almost as if you were there yourself. You know, you have the freedom to explore, pan, well, in 3D, look around! But that’s not really the purpose of video. Video, instead, is to show you a directed stream of images as seen from a camera, possibly as scheduled by a movie director. That is a very different motive than still photography.

Read on →

airbnb discrimination and hoverboards battery safety certification

quorten

2016-12-17

Categories: random  
Tags: random  

Off-topic.

Interesting.

20161216/https://www.cnet.com/news/airbnb-discrimination-black-and-latino-neighborhoods-report-hotel/

Oh, interesting. Hoverboards. UL 2272 certification was created in response to all the hoverboard hazards. It certifies the safety of the electrical and battery systems for a hoverboard. Particularly interesting is the language on the site that refers to “high energy density batteries.” Indeed, these have become a new hazard similar to the hazard of gasoline, only they are even more dangerous.

20161216/https://www.cnet.com/how-to/buy-a-hoverboard/
20161216/http://www.ul.com/hoverboards/

DSLR cameras with 4K video available? And other camera information

quorten

2016-12-16

Categories: pentax-k-1-camera  
Tags: pentax-k-1-camera  

Wait, wait, wait, there are DSLR cameras with 4K video support available? Indeed, there are, and they were released early this year, just like the Pentax K-1. But Pentax doesn’t have any such offerings.

The difference? They tend to have lower density image sensors, and they cost a lot more. They increased cost is probably due to the use of more expensive internal electronics to shuttle around that kind of extra bandwidth, along with needing to pay for additional patent royalties to distribute software that encodes compressed 4K video. Yikes, ouch, that’s too bad for the patent royalty issue at hand.

20161215/https://en.wikipedia.org/wiki/4K_resolution#Recording
20161215/https://en.wikipedia.org/wiki/File:Taipei_IT_Month_Sony_FDR-AX1_20131130_2.jpg
20161215/https://en.wikipedia.org/wiki/List_of_4K_video_recording_devices
20161215/https://en.wikipedia.org/wiki/Canon_EOS-1D_X_Mark_II
20161215/https://en.wikipedia.org/wiki/Canon_EOS_5D_Mark_IV
20161215/https://en.wikipedia.org/wiki/Nikon_D5
20161215/https://en.wikipedia.org/wiki/Nikon_D500
20161215/https://en.wikipedia.org/wiki/Sony_Alpha_7#.CE.B17S

And you ask, what about Sony’s cameras? They use a myriad number of different lens mounts. Ouch. And I thought the purpose of interchangable lenses was to eliminate the issue of needing to buy new lenses of every different type for different cameras! Well, in some sense, it is.

20161215/https://www.dpreview.com/reviews/sony-alpha-a7r

Read on →

Choice of 3D scanning technology continued

quorten

2016-12-16

Categories: 3d-scanning   3d-scanner  
Tags: 3d-scanning   3d-scanner  

Choice of technology continued. Photogrammetry provides a practical way to make 3D scans of landscapes and other large objects where it is impractical to project structured light onto the surface.

  • Like Mount Chiginaugua.

Alternatively, structured light can be used to assist in scanning objects that do not have enough texture of their own for photogrammetry.

Also, another technique with similar characteristics is depth-of-field 3D scanning, using the contrast of a large depth-of-field lens to compute depth. However, this is another technique that requires surface texture in order to work well, so the same rule applies with structured light.

Another idea for 3D scanning. Rather than sweeping a laser across an object, you entirely use contrast thresholding and sweeping the camera focus with a narrow depth-of-field lens to determine depth. Advantage: faster photography is possible with a wider aperture, and there is better noise stabilization in the recorded images. Disadvantage: it might not be possible to increment the focus of your camera lens in as small increments as are the case with a low-cost, continuous sweep DC motor.

Again, note that you may need to project a light pattern onto your object in order to get sufficient surface texture.

Read on →