Strain Calculation by Image Processing
The experimental setup is mentioned to calculate area strain with image processing technique has been mentioned in the previous page. Actuation images of the DE film are taken at 0.5V interval on regulated DC supply which translates to 1KV at DE sample. For every DE sample the actuation experiment is carried out and the images are obtained. Image processing techniques have been used to process the actuation images of different sample. The basic idea in calculating the strain is to find the area of the DE film in terms of number of pixels and then to multiply it with the area of a pixel. The camera used for taking the images must be having high resolution so as to decrease the error in the determination of strain.
The Specifications of the image used are as follows:
a) Camera: Sony DSC-W620
b) Exposure time - 0.2 second.
c) Focal length - 12 mm.
d) Resolution - 4320 x 3240.
e) Colour representation - RGB.
Steps followed to calculate the area strain of a dielectric elastomer using image processing technique
The steps followed for the determination of area are as follows:
1. Cropping and converting the image to gray-scale to reduce computations.
2. Converting gray-scale to binary by keeping threshold.
3. Removing the unclear part inside the actuation area which is formed due to reflection of light while taking image.
4. Determining the number of pixels in the actuation area.
5. Calculating strain from the number of pixels.
6. Once initial area and final area are known area strain could be calculated easily.
The steps are described in detail in next page.