high frame rate, motion detection

High Frame Rate (fps) Motion Detection and Picture Capture

While video surveillance/security/monitoring apps capture video at 30 frames per second (fps), Gotya photo surveillance can capture up to 15 fps when set to high-speed motion detection. This means that you will not miss anything and be able to capture a detailed record of a motion triggered event, while realizing the benefits of photo survellance namely low upstream bandwidth usage, ability to operate on slower speed mobile data networks (2.5/3G) or slower WiFi, if high-speed WiFi is not available or is too costly, and capturing only the frames that contain motion.

And as mobile devices (smartphones and tablets) track Moore’s Law and continuously get faster CPUs, more RAM, and faster network chips,  Gotya leverages that into ever faster picture capture frame rates – 15 fps may not be the maximum.

To illustrate Gotya in high-speed (high frame rate / fps)  motion detection mode, we used a Nokia Lumia 820 Windows Phone 8 which is a 1 year and 8 months old device (began shipping in September 2012). This device has a Qualcomm Snapdragon S4 CPU (Dual-core 1.5 GHz ) and 1024 MB RAM. One of Gotya’s core benefits is enabling consumers to use their old smartphones and tablets as motion detection cameras.  A 20-month old device is representative of a real world use case, where smartphones are typically updated after 18-24 months (and often times even  faster with upgrade programs like T-Mobile JUMP).

To set Gotya for high-speed motion detection, go into Camera->Advanced Settings and set Object motion all the way to fast (20) as shown below.

motion detection speed

Object motion set to 20 (fast)

Then aim and calibrate the Gotya motion detection camera as usual – the setup for this example is shown below. The important thing to note about calibration and how it affects motion detection / frame capture speed is that the smaller the active window, the faster the motion detection gets. In this example, we’ve set the active window to about 80% of the camera viewfinder to cover the path to detect anyone walking on it and to ignore motion outside of the active window. If the active window was say 50%, motion detection speed would increase proportionally.

motion detection camera calibration

Active windows size (orange frame) ~ 80% of viewfinder

The GIF  below shows 32 frames captured in 4 seconds by Gotya with the above settings.  Included below the GIF are the first and last picture in the sequence from the Gotya Web Gallery, with timestamp in the top left corner. The first timestamp is 11:16:38 and the last timestamp is 11:16:42 = total of 4 seconds.

This means Gotya running in fast motion detection mode on a 20-month old device captured 8 frames/second.

motion detection app, fps, photo surveillance app

32 frames captured in 4 seconds on an 20-month old smartphone (Lumia 820)

 

motion detection app

Frame 1 of 32

motion detection camera app

Frame 32 of 32

 

In a future post when Gotya for Android is released (in the coming weeks), we’ll compare the frame rate capture of the 18-month old Lumia 820 to a Google-Asus Nexus 7 (2013) Android tablet which is 10 months old as of the date of this post, and has a quad-core 1.5 GHz Snapdragon S4 Pro CPU and 2GB RAM. After that we’ll benchmark a  a current device that started shipping in 2014. This will illustrate the effect of Moore’s law on Gotya’s maximum frame rate capture and we expect to be approaching or exceeding 15 fps as claimed at the top of this post.

(Featured Image courtesy of www.empirecinemas.co.uk )

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