## 6 Methods for Reconnaissance Support
The transition of the image on the sensor into the image in the preview consists of the software cropping the top and bottom of this image: \(\frac{H_{obj}^{p}}{H^{p}}=\frac{H_{obj}^{p}}{HP+H^{H}}\), where \(H^{S}\) denotes the height of the sensor, \(H_{obj}^{p}\) denotes the object height in the preview of the mCOP application, \(H^{p}\) denotes the height of this preview, and \(H^{d}\) denotes the difference in height between format 4:3 and format 16:9. The formula after calculating the described transitions, \(D=\frac{f+H_{obj}^{s}\left(H^{p}+H^{H}\right)}{H^{S}H_{obj}^{s}}\), considers image sensor height. This is rarely specified in the documentation provided by the smartphone producer. Android version 5.0 (API 21) [21] (and above) delivers a new version of Camera API (Camera2), providing information about camera sensor size. However, on Android devices with software below API 21, the sensor size must be entered manually or calculated. The crop factor parameter describes a camera sensor size compared to a reference format. This concept refers to digital cameras (located in smartphones) relative to a 35-mm film format (43.3-mm diagonal) and is an important parameterin the calculations, as it describes the size of projected pictures. The most commonly used definition of a crop factor is the ratio of a 35-mm frame: \(CF=\frac{d_{3 mm}}{d_{s}}\), where \(CF\) denotes the crop factor, \(d_{35 mm}\) denotes the diagonal of a 35-mm film format, and \(d_{s}\) denotes the diagonal size of the sensor. Another definition of CF is \(CF=\frac{E_{sf}^{35 mm}}{f}\), where \(Eq_{f}^{35 mm}\) denotes the 35-mm equivalent focal length. From the relation between the focal length and the 35-mm equivalent focal length, we can obtain the CF value. As a result of previous assumptions, we can obtain a diagonal measure of the image camera sensor: \(d_{s}=\frac{d_{3 mm}}{CF}\). In order to calculate sensor dimensions (format 4:3), we apply given relationships, \(\left(4x\right)^{2}+\left(3x\right)^{2}=d_{s}^{2}\), \(W^{\text{S}}=4\frac{d_{s}}{5}\), \(H^{\text{S}}=3\frac{d_{s}}{5}\), where \(W^{\text{S}}\) denotes the width of a sensor. Information about the camera angle of the view is located in the Camera API parameters. The angle of a view can be computed from the effective focal length and chosen dimension, and thus we obtain the height of the sensor: \(\alpha=2 arctan\Big{(}\frac{S}{2f}\Big{)}\), \(H_{s}=tan\Big{(}\frac{AOV_{\text{bar}}}{2}\Big{)}*2*f\). The proposed alternative Method B uses the additional measurement of the object and the distance taken from a location where the distance is known or has been previously evaluated. In the case where the height of the object cannot be determined, there are methods to utilize the proportion or relative size comparison. As a result, Method B requires two separate measurements (surveys) taken from two different locations (distance from each other more than 5 m). The proportion between heights of an object on a sensor and the distance difference obtained from these two measurements is equivalent. Thus, Method B calculations determine that \(\frac{A}{f}=\tan\theta_{1}=\frac{B}{f}\), \(\frac{B}{f}=\tan\theta_{2}=\frac{H}{D-m}\), \(\frac{m}{D}=1-\frac{A}{B}\), \(D=\frac{m}{1-\frac{A}{B}}\), where \(m\) denotes the distance difference between two measurements, \(A\) denotes the object height on the sensor from the first measurement, and \(B\) denotes the object height on the sensor from the second measurement.