Wageningen, 2 April 1997 - Noldus Information Technology today announced a new version of EthoVision, its video tracking, motion analysis and behavior recognition system. EthoVision 1.90 offers several important new functions relative to version 1.80. 

This major new addition to the software allows you to perform keyboard event recording during a video tracking session. You can use this to score any behaviors of animals which cannot be recognized automatically by EthoVision (e.g. grooming, feeding, sexual behavior), or to fine-tune a parameter for the automatic detection of individual or social behavior (e.g. rearing). The event recorder in EthoVision is comparable to that in The Observer, but of course not as comprehensive. You can define up to 30 behaviors and assign those to keys of the keyboard. Behaviors of different animals (in the same or in different arenas) can be mapped to different keys. During a tracking session, behaviors can be recorded in a press-and-hold-down fashion, or by pressing separate start and stop keys, or as mutually exclusive states. The behavioral events are stored together with the track data. After a session, EthoVision will calculate frequency of occurence, latency, duration, and various other statistics. Of course you can also export the recorded behaviors to The Observer for further analysis (lag sequential analysis, time-event plots, etc.).  

Prior to analyzing a track, EthoVision converts the coordinates in the digitized images (in pixels) to real-world coordinates of the observed scene (in centimeters). In order to obtain correct distances, the system must be calibrated. The calibration method present in older versions uses a simple model based on a linear relationship between distances in the real world and distances in the digitized image. To let EthoVision compute the calibration parameters, all you needed to do is enter the real-world distance between two user-selectable points within the digitized image. This calibration method works fine for many setups or if absolute distance measures are not critical, but it falls short if you use a camera lens with a short focal length (wide-angle or fish-eye lens). The effect is clearly visible in the figures. The magnitude of the distortion varies with the position in the image. This distortion can cause systematic errors in vector-based measurements. To minimize the effect of non-linear distortion, EthoVision 1.90 offers an advanced calibration method (besides the standard method). The advanced method uses a complex model that compensates for both differences in aspect ratio and lens distortion. The parameters of the model are calculated by EthoVision on the basis of a set of user-specified data. During analysis, the model is used to reconstruct the original, real-world coordinates. 

EthoVision 1.90 offers video tracking at high image resolutions, with a maximum of 512 x 512 pixels. This means that the maximum arena-to-object size ratio has doubled in both directions compared to version 1.80. You can now reliably track objects which are 150 times as small as the diameter of the arena. This is good news for entomologists! 

For more information, please contact the product manager of EthoVision.