High fps motion detection and picture capture with Nexus 7

In the first post about how to capture high frame rate / high # pictures per second with Gotya, we used a 20 month old Lumia 820 that captured 8 fps and said that we’d update this post series with a Nexus 7 (2013) to show how Moore’s Law – that is, the continuous improvement in price/performance of computers including tablets and smartphones over time – both in terms of hardware like CPU and GPU and software such as O/S – means that Gotya will also continuously improve it’s maximum fps picture capture as new, more powerful devices come out.

Now that Gotya for Android is out, we’d like to share the update on how the Nexus 7 (2013) performed. This is now an 11 month old device (started shipping July 2013) and it’s successor, the Nexus 8, is already expected to be announced at Google I/O on June 25th and will be another big step in performance , less than a year since the previous generation device started shipping. So the pace of performance improvements is only increasing.

The Nexus 7 (2013) captured 10 fps in our like-for-like test in terms of camera calibration and settings, at the same location and action sequence (somebody walking at normal pace). In fact this time the active window was slightly larger (which decreases the fps) and there are six times more pixels to scan and analyze in order to perform the motion detection  (1920 x 1200 = 2.3M on the Nexus 7  vs  800 x 480 = 384K on the Lumia 820). Even still, we observed a 25% fps performance increase over the 8 fps captured by the Lumia 820 Windows Phone.


motion detection camera, Android security camera app

Nexus 7 Gotya motion detection camera calibration from Nexus S remote controller


Here’s the GIF of the 40 frames captured in 4 seconds

Gotya motion detection app for Android, Android security camera app

10 fps captured by Nexus 7 (2013)

And here’s the first and last frames of the GIF with the timestamps in the top left showing the 4 second duration.

android security app, nexus 7 motion detection camera

Frame 1 captured by Gotya on Nexus 7



android security camera app, nexus 7 motion detection camera app

Frame 40 captured by Gotya on Nexus 7


It’s important to highlight that these are real-world settings designed to capture pictures of a person walking at normal speed in a specific area (active window) – the path leading up to the entrance.

Gotya’s ability to capture high fps means that the details of an incident will be captured and you won’t miss a thing even when using devices 1 year old and more, making Gotya a perfect use for that old Android, Windows Phone, or Symbian device sitting around in your drawer. It also means that you don’t need a video surveillance app to capture high fps. Video apps capture 30 fps and we’ve just shown that Gotya on a one year old device captures 10 fps which is quite respectable given Gotya’s dramatically lower price and bandwidth requirementsas compared to video surveillance apps.

How does Gotya do this? With high performance native code and clever optimizations where the platform would otherwise slow down picture capture. No cross-platform IDEs or SDKS here.

We’ll provide an update with a 2014 device, maybe even the Nexus 8 or a newer spec Windows Phone 8.1 (or both),  and see how many fps Gotya captures with that new high performance device. We wouldn’t be surprised to see it real close to 15 fps.

Download Gotya Security Camera for Android now and see for yourself.


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)


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Frame 1 of 32

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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 )

video surveillance, photo surveillance, home monitoring, security camera

Photo vs Video Surveillance App Costs [INFOGRAPHIC]

Video surveillance apps like Dropcam are great. They have awesome features (720p HD video, live streaming, night vision, 2-way audio, digital zoom, wide angle lens, motion and sound-triggered alerts).  And kudos to Dropcam for having such an awesome feature set and enabling folks to set up their own home video surveillance/monitoring system that they can control from their smartphone,  bypassing the big incumbent security companies with their $50 for 36-month (that’s $1,800) monitoring contracts and $99-$300 for installation charges.

However, even though Dropcam eliminates those expensive “professional” installation charges and monitoring contracts from companies like ADT Pulse,  those awesome video surveillance features listed in the opening paragraph above come at a correspondingly awesome (translation: high) price.

Total cost of ownership (TCO) to the consumer for an independent (aka Over-The-Top) smartphone based photo or video surveillance app and cloud service can be broken out into three main categories:

1) Camera

2) Cloud Service for monitoring, alerts, and picture storage or video recording

3) Upstream Internet connection

In the case of Dropcam video surveillance, continuous (up)streaming of video is required for motion detection (which is done in the Dropcam cloud) and video recording. So if you want any record or evidence (i.e. recording) of what happened, you’ll need to sign up for the Dropcam Cloud Recording (CVR) service. You can get motion alerts and view live video without the service, but to save any video footage you’ll need the CVR service.

The Infographic below compares these three cost categories and feature sets for  a  photo surveillance app (Gotya) and a video surveillance app (Dropcam). If you can afford the camera and monthly service fees and have access to affordable high-speed Internet, it’s clear that video surveillance offers a richer feature set than photo surveillance.

However, if you’re on a tight budget, don’t have high-speed WiFi at home (or it’s very expensive) or only have 3G Internet access, and are looking for a way to build your own low-cost security/surveillance system, you might want to take a look at Gotya.

(Note: Internet access charges are based on $110/month for a 50Mbps/down and 5Mbps/up Internet connection in Sao Paulo).

Check out the Infographic below for a comparison of the costs and features of photo (Gotya) vs video (Dropcam) surveillance apps.

photo surveillance, video surveillance, app, security camera, home monitoring