LED Chaser Display

Measure time-related performance parameters

Isolight chart holder, LED chaser display
Isolight includes a 100 LED chaser display.  Simple in operation, the LED chaser lights each LED in sequence.  Each LED stays on for a user-settable time period.  The LED chaser can be used to measure a wide range of time-related imaging parameters.

Measure from Milliseconds to Minutes

The LED chaser step time is programmable from 0.1ms per step to 1.0 second per step. The total display cycle time is from 10.0 ms to 100 seconds. You can easily measure the fastest single frame exposures all the way to minute-long exposures or video clips.

Emphasis LEDs for Easier Counting

Counting a lot of LEDs is tedious.  To make the process faster and more accurate, Isolight features an optional LED emphasis mode.  The emphasis mode makes every fifth, tenth, or 33rd LED noticeably brighter, so that it stands out.  The emphasis LEDs let you quickly count blocks of LEDs the same way tick marks on a ruler make measurements easier.

Auto LED Brightness

Similar to other Isolight components, the LED chaser LED brightness can be set either manually or automatically adapt to ambient light levels.  The “auto” mode adjusts the LED brightness so that the LEDs are clearly visible at any light level but not so bright as to introduce light pollution.

Audio Output for Audio/Video Testing

Isolight can also generate audio markers (beeps) synchronized with the LED chaser operation. Audio markers can be generated at the start of the line, for every emphasis LED, or for every LED.

Measuring Still Image Time Parameters

  • Exposure Time – the most basic measurement.  Set the LED chaser at an appropriate step rate and capture an image.  By counting the number of lit LEDs, you can measure the image’s exposure time.

Measuring Video Image Time Parameters

  • Frame Rate – Set the LED chaser so that several LEDs are visible in each image.  The frame rate is the number of LEDs from the start of the bar in one image to the start of the bar in a second image
  • Frame Rate Jitter – the frame time from one image to the next should be constant.  If the frame rate varies more than one LED, there is significant frame rate jitter in your system
  • Dropped Frames – Every LED should be visible in at least one video frame.  If any LEDs are missing from the sequence, your system is dropping frames.  You can estimate the drop-out period as well
  • Audio/Video Synchronization – Audio/video track synchronization can be measured by capturing video with audio markers enabled for emphasis LEDs. Each audio marker should sound during the associated video frame. The amount of leading or lagging indicates the audio track desynchronization
  • Auto-Exposure Behavior – Using the auto LED brightness mode, you can watch the exposure time change from frame to frame as you adjust the light level.  This is very useful for measuring and auto exposure convergence time, stability, and over/undershoot