# Distance Assessment by Object Detection--For Visually Impaired Assistive Mechatronic System
## 6 Conclusions  
Measuring the distance to an object in addition to the detection and recognition of objects stands as a real advantage for any assistive device used by visually impaired personsin their everyday life. Many devices use video cameras, but few use additional systems to give complementary and accurate information. The processing of digital images captured by cameras, respectively the analysis at the pixel level and the interpretation of significant information, leads to the knowledge of the mechatronic system environment. The two new proposed methods (procedures) for distance assessment using object detection have proved to be useful for the motion strategy of the robotic arm--a component in the assistive mechatronic system for visually impaired persons. Considering the low-cost camera subsystem, the authors' main conclusions and targets for further research development are as follows. * Good results are obtained when the direction of the camera has a small deviation from the normal direction of the object plane (focused tissues or objects, signs, etc.). An improved method for object detection could use the stereoscopic capability of the low-cost cameras. * The maximum errors in the distance evaluation (by sign detection with low-cost cameras) exceeds the recommended 10 mm allowable error. This can be managed from the iterative inverse kinematics procedure, because the best results in the distance evaluation are obtained at approx. 250 mm value for SET-11 images when the error is 1.64% (4.1 mm). The error value also depends on the video camera focusing on the object. The focus is not always the same for the left and the right camera. * The errors in the distance evaluation method also depend on the camera resolution. The mathematical function between the real size of an object and the pixels of the object in a photo is not easy to manage and can lead to errors. However, because this idea is at the early stage of development and almost everyone can now use a simple smartphone with low-cost photo/video cameras included, this method will receive attention from many researchers in the future. When considering the RPLIDAR--HQ camera subsystem, the authors point out that at the date of this research, no study was identified in the literature that included the combination of a Raspberry Pi HQ IMX477 camera and a RPLIDAR A3 laser scanner. The multi-sensor conceptual approach is classic, but the combination of equipment is new; the results of their collaboration were unknown prior to this study. Basically, this paper presents the research and results obtained in the concept development and testing phase for a new visually impaired assistive device (VIPs-Walker). This device aims to be of real help to people with visual impairments, but also to people with other associated/multiple disabilities (as, unfortunately, happens many times). Because people with disabilities are of relatively poor social condition and their living resources are limited (especially in our country of Romania), this device is intended to be available at a price that many of these people could afford. As previously mentioned in the paper, this research is based both on the real experience of one of the authors as well as on previous research (on target groups) for identifying the needs and requirements that the device would meet. The target groups included young people with mild cognitive disabilities associated with visual impairment, aged between 14 and 28, and attending vocational school, high school, or post-secondary courses in an educational institution for people with special educational needs (SEN). This research pointed out that there are differences in the adaptation to and perception of surrounding objects, recognizing simple 3D objects used in math classes (sphere, pyramids, parallelepipeds, etc. ), and, not least, spatial orientation in the halls of the institution. In fact, the virtual simulation of the robotic arm motion to grab the object resulted from the urgent need for some people in the group to take a glass from a shelf.