Photogram - Time evolution in one frame

Desktop application for time-slice photography

A time-slice is a fixed picture that visually represents a scene throughout time. See examples below.

The input is the series of time-lapse images, showing for instance a sunset. After very short process, the time-lapse is transformed into a time-slice. By scanning the time-slice horizontally, the viewer can appreciate several extracts from different moments in time.

The aim of this page is to explain how the Photogram app works and thus how anyone can create their own time-slice in a few simple steps.

Transforming a time-lapse into a time-slice:

The input is a conventional time-lapse.

After choosing your preferred settings, hit the render button and get your result :

Time evolves within the time-slice: in the same result we see moments from before sunset and from after.

Settings to tweak :

1. Choose the range of pictures

Within the whole time-lapse, set the left and right cursors in order to fix the start and stop points in time for your time-slice.

2. Choose the number of desired stripes

This slider sets how many pictures will be used; they will appear as vertical stripes.

3. Choose the direction of the time-lapse within the time-slice

Time can flow from left to right, right to left, inside out, or outside in. For instance when choosing left to right, the beginning of your time-lapse (or chosen range) will appear at the left of the time-slice, and the end of the time-lapse (or range) will appear at the right.

Notice how I already render and easily change some parameters to get a better result.

4. Save your file

After finding a satisfying render, click on save to export your time-slice.

An "open folder" button is available in the export settings at the left.

The main process is finished ! The next steps are related to specific and non mandatory settings.

5. Shift the center

In the centered modes inside-out and outside-in, you may have seen a yellow stripe appearing during the configuration. It marks the point where the time-lapse transitions from progressing forward, like from 7pm to 8pm, to reversing direction, moving back from 8pm to 7pm in this example.

These settings allow to shift this center, in order to emphasize a point of interest which is not directly located in the center of the image composition.

6. Local variations

Initially, time evolves in a linear manner (constant step in time between two pictures). This tool, based on a Gaussian distribution, allows to amplify or diminish a specific period of the time-lapse.

Notice how the purple tints of the sky appear in the first photogram and vanish in the second one.

Thanks to local variations, you can smoothly but strongly emphasize a specific period of your time-lapse, for instance some nice colors in the sky, or to diminish one where the lighting would not be especially interesting.

7. Add timestamps (new)

This table enables to print the original picture timestamps on each stripe.

This option is especially useful to help the understanding of what a time-slice is.

To test the App you can use the following image samples :

This desktop application is a personal project created during my year of Erasmus exchange at the Technical University Dresden, Germany. For any suggestion or critic please contact me.

C++

OpenCV

Qt

Ubuntu

To see more examples of time-slices, click on "Time-lapse" below.

error: