This depth of field is directly correlated with the depth resolution of the 3D reconstruction.3.?Acquisition SystemThe 2D image stack is performed by a displacement of the depth of field in order to scan the considered scene. According to Figure 1, the displacement can be obtained in several ways:�C Displacement of optical system�C Displacement of object�C Displacement of lens (zoom)The last kind of displacement has the drawback of changing the depth of field, which must be constant between each acquisition, and leads to a non-constant magnification. These magnification effects are explained in details in [6].Therefore, there remains the possibility of moving the optical system or the object but the latter solution is not possible for crops. We selected the displacement of the acquisition system to vary the focal plane.
As explained in [7], by varying the dco distance following a constant step and keeping the optical parameters fixed (aperture and focal length), a constant magnification appears during the acquisition.In order to perform displacement of the optical unit, we use the system of Figure 2. The optical unit is centered on the desired field of view and two power LEDs are used to illuminate the scene. A stepper motor is coupled to a linear displacement with trapezoid screw and allows moving the optical unit incrementally and precisely. The motor control is carried out by a micro-controller associated with a power card. Both this card and the LEDs are powered by a 12 V battery with a 12 V/5 V supply for the micro-controller card.
The acquisition system is transportable and self-powered, which allows acquisitions in the field. The camera and the micro-controller are both connect
Each pathological change modifies the chemical composition of the human body, including biological fluids. This fact is utilized in medicine in the diagnosis of various diseases [1]. Chemical analysis of the biological fluids such as blood, urine, saliva, sweat, and exhaled air may allow early recognition of many diseases such as lung cancer, breast cancer, prostate cancer, asthma, tuberculosis, bacterial and viral infections or it may help to monitor blood dialysis processes [2�C19]. Unfortunately, the performance of currently applied medical apparatus is limited. They do not allow identification and determination of the concentrations of all the chemical compounds present in the human body, which are critical from a pathological effect standpoint [20].
On the other hand, recently there have been many literature reports on the applications of electronic noses in biomedicine [1�C19,21�C29]. The electronic nose is a device equipped with a set of non-selective chemical sensors, the response signal of which is correlated Dacomitinib with the holistic information obtained from a smell profile of a gas sample or headspace phase of a liquid sample [30�C36].