Whether you’re new to high-speed technology, or want to add to your existing set of skills, the Photron FASTCAM Viewer 4 (PFV4) software has something for everyone. In the following blog, we highlight the PFV4 functions that serve to enhance Image Processing in a variety of ways; let’s take a look!
As seen in the image above, the “Adjustment” menu at the top of the PFV4 User Interface includes LUT (Look Up Table), Color Correction, Filters, HDR and Binning Functions that can be used to enhance both LIVE and SAVED Images from the Photron cameras. These functions are detailed in the next sections.
LUT – Look Up Table
The graph in the LUT menu (Figure 1, right-hand column), represents the Default linear response of the Photron CMOS sensors in PFV4. The user can modify settings for Gain, Gamma, Contrast and Brightness as needed through the selection of several Presets (DEF 1, DEF2, DEF 3, DEF5, DEF6 and USER). Any changes can be applied to the entire image or to a user-selectable area. Color images also allow the user to select adjustments to Red, Green and Blue channels “globally” or individually.
Notice the change in the appearance of the images in Figure 1 & Figure 2, as well as the graphical representations, when the Mode is changed from DEF 1 to DEF 3. Many additional details of the equipment being studied are now clearly visible to the viewers. The “User” setting is generated by modifying the settings of the (4) individual tools (Gain, Gamma, Contrast and Brightness). These custom settings can also be SAVED to the camera as a new Default at boot up.
Color correction is defined as “a technical process that fixes color issues and makes footage appear as naturalistic as possible”. Settings for Daylight, Tungsten and custom User conditions are available in PFV4. The saturation of color can also be adjusted as desired.
The “Filters” menu provides the following options:
- Median Filter: This filter has the effect of removing “salt and pepper noise”.
- Gaussian Filter: This filter has the effect of smoothing an edge.
- Edge Enhancement Filter: This filter has the effect of sharpening an edge.
- Spot Noise Reducer: This filter removes the specified pixel size of noise.
- Zoom Interpolation: This filter allows the user to select the interpolation method to be used when digitally zooming an image (Saved OR Live).
HDR (High Dynamic Range)
In images that contain bright AND dark subjects, HDR can be used to enhance the dark section of the image while reducing the contrast of the bright section allowing both to be seen more clearly. Visually, this provides added dynamic range to the image which can be applied within LIVE and SAVED images.
Figure 3 displays the raw image, while Figure 4 displays this same image with HDR Level 3 applied. Now you can see the details on the springs surrounding the main subject of this video.
Binning allows the user to increase the brightness of the image by combining pixels, which reduces the image resolution. By selecting “2 x 2” binning, the vertical and horizontal resolutions will be reduced by one half but the brightness will increase by a factor of (4). Essentially, four pixels become one. The benefit is that noise floor characteristics for this new “super pixel” remain the same while luminance increases. As you can see in Figure 5 above, the Field of View is not impacted by the use of binning.
We hope that this breakdown makes the process of adjusting images easier, and creates a better end result for your project!
(If you’re looking for additional PFV4 functions, check out our blog: High-Speed Video: PFV4 Features and Functions.)