The following is an overview of the Filter tab of captureOEM.
captureOEM includes Preview Filters, which can be selected from the drop down menu. An explanation of these filters can be found below.
| Callback | Effect |
Negative | Used to invert the colors of an image. This filter is useful for turning a positive image into a negative, or to make a positive from a scanned negative. |
Grayscale | This filter converts an image to grayscale. The red, green and blue colors in each pixels are averaged. Then the resulting color is set to grey scale with the average intensity. |
Histogram Equalization | Improves the contrast of "muddy" images by detecting the minimum and maximum pixel values in the input range calculating a linear conversion that maps the minimum intensity value to full black and the maximum intensity value to full white creating an enhanced image by converting all of the pixels of the input image accordingly. |
Saturated and black | Displays areas of saturated pixels and pure black pixels, thereby highlighting areas that have lost detail because it is too dark or too bright. |
Threshold (50%) | The filter does image binarization using specified threshold value. All pixels with intensities equal or higher than threshold value are converted to white pixels. All other pixels with intensities below threshold value are converted to black pixels. |
Low Pass | Smoothes image and reduces random noise, based weighting of local pixel values. |
Median | Reduces random noise, particularly "shot noise" (extreme values of individual pixels), based on median brightness level of local pixel values. |
High Pass | Sharpens image and reduces gradual variations based on weighting of local pixel values. |
Sobel Filter | Detects edges based on gradients (differences) in local pixel values. |
Temporal Threshold | A very simple temporal filter that attempts to remove a bit of noise from images by comparing the current image to the previous image. |
Motion Detector | Given a stream of images, pixel values that are consistent from one image to the next, are shown as black. Similarly, pixels that change from one image to the next, are shown as saturated. |
ASCII | The pixel dN values are mapped to the ASCII character set. |
Bitmap Overlay | Adds a bitmap, such as company logo or a time stamp, on the image. Enter the name and location of the bitmap in the "File Name Box", or use the "Browse" button to locate the file. Notes: The bitmap must be a .bmp file in 24-bit RGB format. The overlay image is placed in the upper left corner of the frame. An overlay image will not be resized if the size of the ROI is changed. |
Crosshair Overlay | Adds a centered crosshair overtop of the display. |