minFilter.md

Min Filter

Introduction

Given an image, we'll replace each pixel intensity with minimum value from its neighbouring pixels, where order of neighbourhood can be variable X ( > 0).

Performance

• Prior to this writing, I wrote concurrent MinFilter implementation where each pixel was getting processed in different worker thread ( depending upon availability in thread pool ).
• Now implementation has been improved by processing each row of image matrix concurrently.
• Previously each thread was doing little work, but for large images ( & for higher order filtering ) communication cost ( work distribution ) was too high due to presence of large number of pixels in image.
• So, I considered reducing number of works created, by processing each row concurrently on possibly different worker threads.
• Check below for performance improvement, due to updating implementation

Sample

I applied both MinFilter implementations on sample of dimension 2560 x 1440, with order value set to 5.

Source	Sink

Before

After

Results

All filters applied on order-0 image.

Order	Image
0
1
2
3
4
5

Thanking you 😊