How to use Pixcavator

How to use Pixcavator

Load image

Start at the Analysis tab. Select an image file from your hard disk by using the Choose file. button on the right. Most popular formats are supported. The image will appear on the left. Select simplification settings

First, choose the threshold for Area. For example, if you choose 100, every object containing less than 100 pixels will be removed from the image. Second, choose the threshold for Contrast. For example, if you choose 20, every object surrounded by an area with gray level that differs from that of the object by less than 20 will be removed from the image. There are 256 levels of gray. If all you want is to sim 19419l1110t plify a photograph, keep these numbers low at first, e.g., 100 and 20. Select also the threshold for Compactness which is a measure of roundness of objects. The last setting is Saliency, which is a smart combination of area and contrast. Other simplification options located under Advanced. are currently disabled but can be introduced by means of the SDK. Select the gray scale option (optional)

Decide if you want the image to be processed as a gray scale (only the blue channel
will be used). The program will run faster. Mark the check box Gray scale in the right lower corner.

Enhance image (optional)

Whether you are interested in analysis or special effects, you may try to enhance the image with some standard image processing tools. Go to the Tools tab. You can adjust Brightness and Contrast by using sliders on the left. On the right, there are some Filters. Erosion thins dark areas and Dilation thickens them. These operations may sometimes improve the accuracy of analysis by eliminating scratches and other imperfections. The image enhanced this way may appear blurred.

Analyze image

Process the image by pressing Run in the Analysis tab. The estimated processing time (2.4 GHz, Pentium 4) for gray scale images is evaluated by the formula: (size of the image)/10,000 seconds. For color images, the time is tripled. Thus it will take about 25 seconds to process a gray scale 512×512 image, 1.5 minutes if it's in color. Simpler images take less time, complex more. The output is the number of dark objects and the number of light objects that appear on the right.

View simplified image

The simplified image is displayed on the right in the Analysis tab. Keep in mind that the displayed numbers are not the numbers of objects in the simplified image. It is the number of objects in the original image that satisfy the simplification restrictions. The updated image serves as an illustration. In fact, some objects may be so small or of so low contrast that they are not visible with a naked eye. You can use the magnification option by right clicking on either image. By default, the program also produces squares placed around the objects - red for dark objects and green for light ones. The center of each square is placed at the center of mass of the object and its area is equal to that of the object. Keep in mind that if the object is very thin and curved, such as a road, its square may miss it. You can remove the squares by unmarking the Show squares box.

View output data

For more output, go to the Output tab. It contains the original image on the left. On the right, it displays the table of all objects in the image satisfying the simplification settings. Locations, areas, etc are displayed for each object. If an object is marked on the right, a square appears around it on the left. The number of objects listed is currently limited by 200. You can mark and unmark groups of images with Mark all, Mark dark, Mark light, Unmark all. Only the blue channel is analyzed. You can save the image with squares by pressing Save image and you can save the data by pressing Export to Excel.

Repeat analysis

The simplification sliders are also provided in the Output tab. The table and the squares are updated as you move the sliders. This way, if you want to process the original image with different settings, you don't have to run analysis again.

Enhance output image (optional)

If you want to enhance the simplified image before saving it, go again to the Tools tab. Adjust the brightness and contrast by using sliders on the left.

Save simplified image

To save the output, press Save File. Most popular formats are supported. You will be prompted with the name of the original image followed by the first two simplification settings. If you want instead to process the simplified image, press Make original.

For the updated version of this guide, visit https://www.pixcavator.com/howtouseit.html.