MetRec Homepage


What is MetRec?

MetRec (Meteor Recognizer) is a software package for the automatic detection and analysis of video meteors. In can be used both to inspect video tapes / DVD offline, and to do online recognition for an automated video system.

MetRec analyses half resolution grey scale PAL (384x288 pixel, 8 bit) or NTSC (320x240 pixel, 8 bit) video frames at rates up to 25/30 frames per second. It stores the appearance time of meteors and optionally a number of frames and a sum image from each event. MetRec is able to compute the meteor brightness, its velocity and equatorial coordinates. The software calculates the limiting magnitude and the size of the field of view covered by the camera. It is able to determine the meteor shower on the fly, and the flux density for each meteor shower.

The software is highly flexible - it can be adapted to each individual system with a number of parameters to be set in a configuration file. All output is written into a logfile. During recognition, the current input signal, preliminary results of the recognition process (e.g. mean subtracted image, regions of interest, segmented and identified stars, ...) and the system state are displayed at the monitor.

How does MetRec work?

MetRec uses a complex algorithm to detect even faint meteors and minimize the false detection rate. Here only a short overview is given. Please, refer to the ReadMe file for a more detailed description.

The program digitizes video frames and subtracts a mean image at first. This way all stationary objects like stars and terrestrial light sources are removed, and only noise and fast moving objects remain. Next the noise variance is normalized ("flatfielding") to ensure constant meteor detection probability in the full field of view.

MetRec then looks for bright elongated spots in the resulting image. If their brightness is above a certain threshold a meteor is hypothesized. The software compares the position of these spot(s) in the current frame with those of similar objects in the previous frame(s) in order to track the meteor. If an object has the right velocity for a meteor and was found in at least a prespecified minimum number of video frames, a meteor is detected.

After the meteor disappeared, MetRec computes the equatorial coordinates of its position in the individual video frames, derives a mean meteor trail, and calculates the velocity and brightness of the meteor. The software checks whether it belonged to one of the showers from IMO's working list. Finally a logfile entry, a sum image of the meteor, a short animation, and a PosDat file entry can be generated and saved.

In parallel, MetRec determines the exact size of the field of view and each minute the limiting magnitude. Based on the figures, the effective collection area of the camera and the flux density of meteor showers is computed. These values can be uploaded to the VMO server for online meteor shower activity graphs.

Hard- and software requirements

To run MetRec you need a PC with a special frame grabber card.

The program is designed for the Matrox Meteor (DOS only) / Meteor II / Meteor II MC frame grabber family. Under Windows, you can install up to four framegrabbers and run four instances of MetRec in parallel on one computer, given that sufficient CPU power, RAM and PCI bus bandwidth is available. Drivers or additional software from Matrox are not required.
MetRec neither works with TV cards or any frame grabber from a different vendor, nor is it able to read AVI or other video files.

The program expects a PAL or NTSC video signal at the frame grabber input. The PC should have a CPU with 700 MHz (DOS/Win98) resp. 1 GHz (Win XP/7) or more. The program will run on slower machines, too. However, this will result in a reduced frame inspection rate causing seriously degraded recognition performance.

MetRec requires at least 32 MB (DOS/Win98) resp. 256 MB (Win XP/7/8/10) of RAM (recommended: 256/1024 MB). The software runs at a graphics resolution of 1024x768 pixels and therefore requires a graphics card with at least 1 MB memory installed. You should have at least 500 MB of free harddisk space (recommended: >10 GB).

The program was originally designed for DOS. Today it comes in three versions: The DOS version runs both under plain DOS or in the DOS mode of Win 95/98. The two Windows versions runs on Windows XP and Win7/8/10 (all 32 bit only). There are only marginal differences with respect to functionality under DOS and Windows.

MetRec does NOT run under 64 bit Windows versions or other operating systems because there is no driver for the Matrox framegrabber available for these OS. Note that Win7 and later requires that a Matrox framegrabber is installed on the same computer. So you cannot run the Win7 version on a notebook, for example, even if it is only used for data post-processing where not framegrabber is required, for example

How does an observation with MetRec look like?

If you setup your camera for the first time or changed the field of view, you need to grab a reference image and measure the position of a number of reference stars to allow for the equatorial coordinate conversion. With the help of the RefStars tool this takes about 10 minutes.

Next you copy and old MetRec configuration file, update a few entries if necessary and start MetRec. The detection software runs autonomous, but you can interactively check the current recognition status and detection results. The program displays both the raw video data stream and different phases of the detection process in real time.

At the end of observation the PostProc tool helps you to browse through the list of detected meteors and to delete false detections in a comfortable way. This takes usually another 5 to 10 minutes.

There are further screen shots for the different programs available which give an idea of the appearance of the software. A description of these shots can be found in the ReadMe file.

Is there other meteor detection software?

MetRec is unique in a number of aspects, but there are at least two other software packages that are comparable and in some aspects even superiour to MetRec.

UFOCapture by the Japanese programmer SonotaCo is a program to detect different types of moving object in the night sky (meteors, satellites, sprites, etc.). It runs on PCs under Windows and comes with additional tools for detailed meteor analysis up to orbit determination from multi-station observations.

CAMS by NASA contractor Pete Gural is an automated video surveillance software to search for meteor showers in the night sky and validate the IAU Working List of Meteor Showers.

Where do I get MetRec?

MetRec is freeware. You may copy, use, and redistribute the software free of charge. However, the author would like to get a short message from everybody using MetRec to know, which versions of the software are used where.

For research purposes, you may obtain the documented C source code of MetRec at request from the author.

MetRec can be downloaded from this site or from IMO's ftp server. You have to choice to download the individual program files for DOS, Win XP, and Win7 or ZIP archives (16.1 MB) / (8.2 MB) / (192 MB) which include the full software package in compressed format. The history file informs you about the latest software changes.

MetRec mailing list

There is a mailing list for questions and announcements (bug reports, software updates) regarding MetRec, as well as for general discussions on video meteor observation. You can subscribe/unsubscribe to that list and browse the list archive at

MetRec Wiki

There is plenty of information about video meteor observation and MetRec available in the Internet. However, there is even more information in the heads of dozens skilled video observers around the world. To capture and share their knowledge and experience, we started a MetRec Wiki as a knowledge base for video observers. You are kindly invited to use the information provided there, or register and contribute further information yourself.

IMO Video Meteor Network

A number of video observers using MetRec have joined forced in the Video Meteor Network. Their aim is to create a large database of high quality single station video meteor observations world-wide.

Copyright and contact address

MetRec is copyright by the author

Sirko Molau

Abenstalstr. 13b

D-84072 Seysdorf


phone : +49/8752/869437

e-mail:; last change: March 6, 2017