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Category: Computer Vision

FFMpeg Side by Side and Tiling Video

FFMpeg Side by Side and Tiling Video

FFMpeg has an interesting ability to join multiple video feeds together. In the past, I had use other video editors to do this. They were limited to 2 camera views. In addition, the second camera screen was scaled down and much smaller than the first video. With FFMpeg, we can join more than 2 camera feeds without resizing. I’ll be quick and to the point in this post so try not to blink. In this example I have 4 cameras…

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FFMpeg Video Sharpening

FFMpeg Video Sharpening

It can seem magical when blurry and low detail video is refocused. Unsharpen masks are the wizard behind the curtain and FFMpeg has this feature. In this post I’ll give some examples of the unsharpen mask. I won’t go into the details or mechanics of how the filter works. This will merely be a quick how to. I’m going to be working with a 30 second clip of video that was shot during the 2012 STP bicycle classic. It was…

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FFMpeg Video Splitting and Splicing

FFMpeg Video Splitting and Splicing

In the last post I mentioned that I used a 5 second clip from a larger video. More often that not, large videos will contain fluff that will need to be trimmed before they are published. There are several media editor that will do this. I’ve used OpenShot Video Editor on my system with good results. However, if you had tens if not hundreds of these trim functions to do, using a GUI like OpenShot would be time consuming. Fortunately,…

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FFMpeg Video Stabilization

FFMpeg Video Stabilization

FFMpeg is a command line video processing tool that has granular, if not sub atomic controls to process audio and video data. It will do a high degree of processing and since it uses the CLI, this allows its use in the background for bulk jobs. This ability puts FFMpeg out front of other processing tools. I’ve used GUI tools like vReveal, VirtualDub, and ProDAD. vReveal was an impressive tool that allowed me to leverage CUDA which used GPUs from…

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Bicycle Helmet Embedded Electronics

Bicycle Helmet Embedded Electronics

Several years ago I purchased a small video camera that was shaped like a flashlight for $50.  It had VGA 640 x 480 30 fps video quality and would record up to 2 hours on a single charge.  I used it to record several bike rides around the county on numerous bike trails.  The videos provided a way to recall the conditions and experiences which I used to plan future trips. A couple of years later I purchased some 808…

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Instantiating the Invisible

Instantiating the Invisible

My initial intent for this post was to elaborate on a concept that I found inspiring. Jörn Loviscach (http://www.j3l7h.de/about.html) had posted a demonstration of a “Poor Man’s Thermographic Camera” that consisted of low cost parts. It scans a scene and processes the visual data to create a thermographic image. The thermo cam consists of a pyrometer sensor (aka non contact ir thermometer), two servos that tilt mirrors, and mounting hardware. It acquires images from the reflection of heat by tilting…

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Netpbm – The Portable Anymap Format

Netpbm – The Portable Anymap Format

Presenting visual data readings into an image file can seem challenging. It need not be thanks to the Netpbm (https://en.wikipedia.org/wiki/Netpbm_format) file formats. First developed by Jef Poskanzer (https://en.wikipedia.org/wiki/Jef_Poskanzer) as a means of sending image data via email. The early adaptations of email did not work well with data other than ASCII. Messages would become corrupt if binary data was included in messages. Today, this is not an issue. However, the work around for this was to use one of the…

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Field Scanning

Field Scanning

Here I’ll cover how sensors can collect readings from an environment and represent those readings in a practical way.  The most common field scanning devices are flat bed scanners and cameras.  These devices either have a line of sensors or an array of them to take readings quickly.  Flat bed scanners typically have a line of sensors that detect light and color.  As the sensors move along the surface of an object, typically paper, they buffer the readings into memory. …

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FOV – Field of View

FOV – Field of View

How can measurements be made when you can’t directly measure them? Measuring the height of a building could be done by someone hanging a string from the rooftop and then measuring the string. What if you can’t get access to the rooftop? What if you needed to measure the span of a lake or height of a mountain? Good luck using that string. Here is how FOV can be used as a measurement tool for objects in pictures, videos, etc….

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SV – Creating Spherical 360 Video

SV – Creating Spherical 360 Video

I had first seen spherical 360 video, which I’ll refer as SV, made by Jim Watters, http://photocreations.ca/3D/mobius_camera_rig.html. It was an accidental on line find. My intent was to research a way to use 2 cameras to create 3D video. He had used a device that he created called a multi camera panoramic video rig. It was a cluster of inexpensive Mobius HD 1080p key chain cameras that were mounted and pointed at various angles. The rig used a total of…

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