# Approach to Automated Visual Inspection of Objects Based on Artificial Intelligence
## 2 Materials and Methods
### Image Acquisition Hardware  
In order to test and select a suitable combination of camera, lens and lighting to solve the selected tasks, technical equipment from the company Balluff was used. Specifically, two cameras--one monochrome 12 Mpx and one colour (RGB--red, green and blue) 5 Mpx and their as associated lenses and lights of various types were selected. Due to the need to illuminate the scene as well as possible, line 100 mm and 200 mm red, white and infrared (IR) lights, circular 100 mm IR light, dome light, surface 200 mm \(\times\) 150 mm lighting and spot light with a diameter of about 30 mm were tested. When scanning the entire surface of the tire at once, light tubes were used, but they are not primarily intended for the given use, therefore constant homogeneity and lighting intensity is not guaranteed when using them. The equipment used in the tests can be seen in Figure 3.  
As part of testing and capturing test images, a monochrome 12 Mpx industrial camera BVS CA-M4112Z00-35-000 from Balluff was used on the basis of preliminary analysis, the basic parameters and image. The selected camera was based on the analysis of the object and external conditions data acquisition supplemented by a Tamr  
Figure 3: Equipment used for image acquisition. Figure 2: Testing elements (defects) [9,26]. 5018-C lens. In contrast to the use of line scanners, it is necessary to ensure optimal lighting when using the camera in order to achieve the desired results, and so the industrial linear LED lights BAE LX-VS-LR200-S26 red were also used. The chosen method of image data acquisition was the use of a monochrome area camera. The research used a sensor from Balluff, namely BVS CA-M4112Z00-35-000 in combination with a BAM lens LS-VS-007-C1/1-5018-C and two red line lights BAE LX-VS-LR200-S26. Choosing appropriate lighting was based on an analysis of possibilities and suitability in various conditions. Particular experiments were performed on an object (Figure 4) which contained multiple surfaces differing in shape, colour and material compared to the tire. The aforementioned figure was captured by a 5 MP colour camera Balluff type BVS CA-C2464Z00-35-000. On this sample was tested IR, red lights for demonstrating impact-specific lighting to capture the image. The first tests were performed with a 200 mm line red light, where the position was experimented with in order to improve the quality of the acquired image and highlight features. Based on this experiment, the impact of colour light to capture the image is clearly recognizable. A label with a red symbol and white background is displayed. The positions of lights markedly change the quality of the captured image. Figure 5 illustrates light above the object, where illuminated top surfaces are significantly lighter in comparison with Figure 5, where light below the object illuminated lower surfaces. For further experiments adapted to a tire, it is expected that we will use a low angle position of lightning to the surface of the tire in order to capture the edges of the text and geometric abnormalities due to very small geometric differences occurring in the range of 0.5-3 mm. The impact of IR light is displayed in Figure 6, where it is compared to 200 mm line red light with a similar position of the lights. Reproduction of experimental conditions as in the previous experiment is not possible due to circular design od IR light. Application of a circular IR light conditionally suppresses geometric edges and focuses on edges generated  
Figure 4: Object for testing of lighting. Figure 5: Demonstrating impact of position line 200 mm red light: ((**a**) light source placed above, (**b**) light source placed below). by different types of material. In Figure 6b there are clear differences in imaging of materials compared to red light Figure 6a. This property is suitable for highlighting abnormalities based on different materials from rubber occur on surface for instance bead wire, polyester casing, metallic belts etc.