Tip #42Kinesense LE

How to stabilise shaky video and clean up noisy frames

Steady body-worn and phone footage with Stabilize, and combine frames with Temporal Median to recover plates and logos from dark, noisy video.

Patricia McCabeSoftware Engineer

Greeting my fellow Kinenerds and welcome to the first of 2019’s tips and tricks blogs. To ease us back into the new year we’re once again going to tackle clarifications. We’ve covered most of the other clarifications in blog #34, #35, #36, #37, #38, #39 and #40 (there are a lot of them!). Today we’ll be dealing with stabilize and temporal median.

Stabilize Stabilize button

Body-worn footage of police officers with four stabilisation points marked, and the stabilised result.

When you get video from bodyworn cameras or phones you often want to stabilise them. This function allows you to correct the camera shake, rotation and changes in angle and zoom level. It woks similarly to Perspective Crop but allows you to fine tune the selection for each frame. You should select some clear features in the video and click on them to assign stabilzation points, four points in total. These points should, if possible, be visible throughout the video segment to be stabilised. The stabilisation points may be fine tuned for a number of frames as required.

Temporal Median Temporal median button

A dark, noisy night frame before and after temporal median filtering.

Temporal Median combines many video frames to filter out high gain noise. This filter, in combination with Histogram Edit, can be useful for recovering licence plates or logos in dark and noisy videos. It works by statically modelling the scene and finding the median value of each pixel over time. This process naturally cleans up non-moving objects and filters out any changing pixels or moving objects. This works best when the video dark, but there is some light present. Completely dark videos cannot be clarified using this method.

To recover a logo or licence plate in this way, go to the forensics tab and find a section of video in which the object to be clarified is non-moving. In the clarification tab, select the clip and add the Temporal Median clarification. The default settings are Median and a Combine Frame number of 30. This is usually optimal.

The temporal median options: Median, Max or Min mode and the number of frames to combine.

The default settings are Median and a Combine Frame number of 30. This is usually optimal. The mode options refer to the pixels. So the max value will return the brightest pixels from all the frames. The combine frames sets the number of frames taken.

Format support

3000+ video formats

Anything playable in Windows Media Player, VLC or FFmpeg is supported, without the manufacturer's original player. Have a format that isn't listed? Our engineers have 17 years experience of dealing with difficult formats.