Night photography and video shooting devices.
VOLKOV Viktor Genrikhovich, PhD in Engineering, Associate Professor
NIGHT PHOTO AND VIDEO SHOOTING DEVICES
At present, night photography and video shooting are widely used in special equipment. This is necessary for forensics, for preparing special operations and documenting their implementation, ensuring the work of the Ministry of Emergency Situations services in eliminating the consequences of disasters, documenting various events at low light levels, etc.
To solve all these problems, night photography and video shooting devices are needed.
These include, first of all, night vision devices (NVD) based on image intensifier tubes (IIT). Using special adapters, the IIT screen can be optically coupled with the film of a photo (movie) camera or with the CCD matrix of a TV video camera. In the first case, this is achieved either by using image transfer optics or by pressing the photo (movie) film directly to the IIT screen using a special mechanism. Transfer optics introduce losses in resolution, contrast transfer, and energy. In addition, it increases the dimensions of the device. Instead of such optics, a ring adapter can be used that allows photo and video shooting using a standard lens directly from the IIT screen, but this will lead to deterioration in image quality and additional energy losses. The contact method of photographing eliminates these losses, but requires the IIT to operate in a pulsed mode, since film exposure is provided by applying a voltage pulse that unlocks the IIT for the required exposure time. This requires the use of a corresponding pulse control unit for the image intensifier tube, which will lead to an increase in the mass and power consumption of the device.
A more advanced method is to couple the NVG with a digital camera or video camera. This allows you to obtain images on electronic media, simplifies and speeds up the process of creating images, replicating them, and allows them to be processed in real time or with the accumulation of information. In this case, the NVG is made in the form of a small-sized attachment for a photo or video camera. In order to transfer the image from the NVG EOP screen to the photo- or video camera's light-sensitive element, lens adapters, which are included with the NVG, are most often used. A typical optical diagram of such an adapter is shown in Fig. 1 [1]. Adapters are called Rayleigh lenses. They can transfer the image at a scale of 1:1, or with an increase of 1.5 — 2.5x, or with a reduction to 0.5x. Reduction is often necessary to match the linear fields of view of the EOP screen and the CCD matrix, as well as to increase its illumination. The relative aperture of the adapter can be from 1:1.5 to 1:6, the focal length from 15 to 40 mm.
Fig. 1. Optical circuits of adapters for connecting NVGs with a photo or video camera
Most often, such NVDs are small-sized night monoculars (“pocketscopes”). The main parameters of NVDs used for photo and video shooting are given in Table 1. The appearance of typical samples of such NVDs is shown in the following photos. In particular, the ORT 3153 pocketscope from Ortec Ltd. (Israel) is shown in photo 1a, and the nature of its docking with a video and photo camera is shown in photo 1b, c, respectively. The NVD consists of interchangeable modules and has corresponding adapters of various types (Fig. 2). The ORT 3152 NVD has a focusing range of 0.25 m – Ґ, a built-in LED illumination source with an emission power of 2 mW at a wavelength of 0.84 μm. The working diameter of the EOP photocathode is 18 mm [2].
Table 1. Main parameters of night vision devices used for photo and video shooting (according to company brochures).
a)
b)
c)
Photo 1 NVD ORT 3152 (a), the nature of its docking with a video camera (b) and a photo camera (c)
Fig. 2. Modular design principle of the ORT 3152 night vision device:
1 – its body; 2, 3, 4 – lenses of different types; 5 eyepiece with eyecup; 6 – adapter for coupling with a photo camera; 7, 8 – adapters for coupling with a video camera 9; 10 – adapter for coupling with a TV camera 11, connected to a TV monitor 12; 13 strap for hanging the device on the hand; 14 tripod
The Javelin Electronics company (USA) offered the Model 222 NVG (photo 2) with a resolution of up to 30 lines/mm and a brightness gain of up to 45×103. The first generation image intensifier has a photocathode diameter of 18 mm [3]. The Model 226 NVG from the same company with a longer range has a resolution of up to 40 lines/mm and a brightness gain of up to 105. The image intensifier has a working photocathode diameter of 40 mm [3] (photo 3). Replacement accessories for the NVG are shown in photo 4. Photo 5 shows a typical view of images from photographs taken through the Javelin Electronics NVG.
Photo 2. Model 222 NVG, docked with a camera
Photo 3. Model 226 NVG with the adapter unit with a removable camera and eyepiece folded aside
a) 1 — stand for the NVG telephoto lens, pistol grip, 3 — Rayleigh lens for coupling the NVG with a TV camera, 4 — strap for hanging on the hand, 5,6 — power batteries, 7 adapter for coupling the NVG with a photo, film and video camera, 8 — Rayleigh lens for coupling the NVG with a TV camera, 9 — biocular magnifier, 10 — NVG mount to the car window, 11 — NVG mount to small arms;
b) 12 — high-resolution biocular magnifier (designed, in particular, for observation from a helicopter), 13 lightweight biocular magnifier, 14 — 17 — lens adapters for coupling NVGs with cameras of various types, 18 — camera, 19 universal Rayleigh lens for coupling NVGs with photo and TV cameras, 20 — type «C» adapter, 21 adapter for coupling NVGs with a movie camera, 22 converter with 2x magnification for NVG lens, 23 — stand for NVGs with a camera for their installation on a tripod, 24 — 29 — ring adapters for coupling NVGs with cameras of various types
Photo 4. Accessories for Javelin NVGs, designed for night photo and video shooting [3]:
a)
б)
Photo 5. Typical view of photos taken through Javelin night vision devices using 35 mm Pentax and SLR Cameras, shutter speed 1/60 sec with relative aperture 1:1.4, Kodak Tri-X film. Photos were taken: on a city street at 10 p.m. (a), on an unlit street at midnight (b)
The most advanced models of NVDs were developed by Intevac (USA) based on the Generation III image intensifier tube [4, 5]. The Nite MateTM 1305/1306 NVD models have a resolution of 450 TV lines in starlight (10-4 lux) [4]. Model 1305 is designed for coupling with a 2/3-inch TV camera, model 1306 with a 1/2-inch format. The power consumption of the NVD together with the TV camera is 6 W, the dynamic range of operation is from 10-4 to 103 lux.
The VNVA-311 SCOUT model by the same company has a focusing range of 0.254 m – Ґ. The NVD can be coupled with a 35-mm photo camera or a video camera using a Rayleigh lens.
Ortek Ltd. (Israel) has developed the TS-5 NVG, which can be coupled with a 1/2-inch TV camera [6]. The EOP photocathode has a diameter of 25 mm. The NVG has a focusing range of 0.25 m – Ґ.
The M944 NVG from Litton (USA) can be used with interchangeable lenses with a focal length of 25 and 75 mm. Accordingly, the NVG has different magnifications and fields of view (table 1), as well as a resolution of 1.81 and 0.68 lines/mrad, respectively. The NVD can be connected to virtually any photo or video camera using a system of interchangeable adapters [7].
NVDs from Night Vision Equipment Company Inc. (USA) models 500A, 520A, 600A are based on an image intensifier with a photocathode diameter of 18 mm [8]. NVDs from the same company (models 400, 400НР, 450) are based on an image intensifier with a photocathode diameter of 25 mm [8]. The NVD can be connected to a 35 mm SLR camera using an adapter.
The Nite-eye night vision device from Varo Inc. Electron Devices (USA) [9] can use a lens with a focal length of 26.8 or 72 mm and, accordingly, have different magnifications and fields of view, as well as focusing ranges of 0.15 m – Ґ and 10 m – Ґ, a resolution of 2.16 and 0.8 lp/mrad.
The NVS-100 night vision device from Optic Electronic Corp. (USA) [10] has a resolution of 28 lp/mm, a focusing range of 2 m – Ґ, and uses an image intensifier with a photocathode diameter of 25 mm.
The MODULUX-225 NVD from Davin Optical Ltd. (UK) uses a reversing lens system with a magnification of G = 1.54x for coupling with a 35 mm camera, and G = 0.66x for coupling with a TV camera. The weight of such a system is 0.64 kg, and the relative aperture is 1:1.1 [11].
Photos 6 – 7 show the appearance of a number of foreign NVDs for joint operation with photo or video cameras [12 – 15], and photo 8 shows photos taken at night through them. Photo 9The external appearance of domestic night vision devices of similar purpose is shown [16 – 17]. The long-range night vision device PDN-K from the company GUP PO NPZ (RF) with the help of adapters allows connection of a video camera with a mounting thread on the lens M37x0.75 (photo 9b) and a TV camera with a lens having a focal length of 12.5 mm and a thread for a filter M40.5×0.5 [16]. The night vision device is mounted on a tripod with a limb allowing a horizontal view within 3600, and a vertical view within ±180. The division value of the night vision device grid is 5 thousand. The angular resolution of the night vision device is 50″.
a)
b)
Photo 6. ORION 80B NVG (a) – on the left and its accessories (on the right, from top to bottom): biocular magnifier, adapter for docking the NVG with a camera, eyepiece; Star-TRONTM NVG docked with a camera (b)
a)
b)
v )
Photo 7. Noctron IV NVG (a) [14]; RF-100 NVG [15] coupled to Ralleflex 3003 SLR camera (b); NSS NVG (c) [8]
Photo 8. Typical photo of images obtained at night through NVGs from photos 6, 7
a)
б)
Photo 9. Night vision device of the “Gelios” series (a); Night vision device PDN-K, docked with a video camera (b)
To ensure night video shooting in low atmospheric transparency (haze, fog, rain, etc.), an active-pulse night video camera M2001 from International Technologies (Lasers) Ltd. (Israel) is used [18] (photo 10). The active-pulse mode of operation allows night video recording in the specified conditions and under the influence of light interference [19]. The M2001 video camera has a sensitivity of 10-4 lux, a field of view angle smoothly adjustable within the range of 4 — 400. The radiation power of the pulse laser illuminator is 10 mW at a wavelength of 0.85 μm. The supply voltage of the device is = 10 — 16 V, the consumption current is 1.5 A (at a supply voltage of = 12 V), weight is 9.5 kg, dimensions are 585x280x240 mm. The range of night video recording in difficult visibility conditions is 100 m.
Photo 10. Active-pulse video camera M2001
All the above mentioned devices operate in the spectrum range of 0.4 – 0.9 µm. However, in recent years there has been interest in the ultraviolet (UV) spectrum range. Until now, the use of UV systems was hindered by strong absorption of UV radiation in the atmosphere, low brightness coefficients in this spectrum range of typical observation objects, and the complexity of manufacturing UV lenses. However, the UV spectrum range also has an advantage: under the influence of UV radiation, fluorescence is observed in the visible spectrum range, in particular, of oil products on water and on land [20]. To implement this advantage, the work [20] reported the creation of the KTV-14 UV TV camera. It included a second-generation image intensifier with a CsTe photocathode, coupled with a CCD matrix. The system includes a TV monitor and a video recorder. The TV camera operates in the spectrum range of 0.26 – 0.38 µm, has a resolution of 400 TV lines, a field of view of 40, a sensitivity limit of 10-16 W/El, a supply voltage of 27 V, a weight of 2.8 kg, and dimensions of W130x210 mm. Flight tests of the system on an An-30 aircraft showed the potential of video filming in the UV spectrum for indicating oil spills on water and land, and objects of anthropogenic origin [20]. However, the greatest effect should be expected from the use of UV devices for photo and video filming in forensics [21]. In particular, the company SPEX Forensics (USA) has developed the RUVIS (Reflective Ultra Violet Imaging System) device, a system for converting UV images into visible ones [21]. The main application of the RUVIS device is the detection of latent (hidden) fingerprints on smooth non-porous surfaces without processing or damaging the evidence (plastic bags, credit cards, photos, glossy magazine surfaces, vinyl and linoleum coverings, etc.). The RUVIS device is also used to detect bite marks, bruises, and shoe sole prints that are not visible when illuminated with ordinary white light. The RUVIS device allows you to remotely inspect a room upon entering it, and detect blood when used together with Luminol. The device intensifies the chemiluminescence of Luminol, making it possible to visualize even the smallest traces of blood. At the same time, the device does not cause fatigue and does not pose a danger to the operator. The SC-VIEWER device consists of an objective/EOP with a UV photocathode and an eyepiece. But with the help of an adapter the device is connected to a 35-mm SLR camera (photo 11a), to a digital video camera SC-DIG and to a TV camera SC-CCD. The video signal of the latter can be output to a video projector, to a computer with digital data processing, to a video monitor, and instead of it – to video glasses (head-mounted display) – SC-GOGGLESSC. To ensure dynamic photography in the UV region of the spectrum with high resolution, the SC-FM2 device is used together with the SC-VIEWER (photo 11b) [21].
a)
б)
Photo 11. Connecting a 35 mm SLR camera to a SceneScope device (a), the SC-FM2 system together with a SceneScope device for direct photography in UV light (b)
NPO GIPO (Tatarstan) has developed an optical-electronic device “Korona” [22] for detecting faults in high-voltage power lines in the UV region of the spectrum. The device has a detection range of 5–150 m, a spectral operating range of 0.25–0.35 μm, magnification G = 5x, a field of view of 100, supply voltage = 3.5 V, a weight of 0.9 kg, and dimensions of 300x110x150 mm. If necessary, the device can be coupled with a photo or video camera.
MNPO «Spectr» (RF) has developed a combined device PK-1 for checking documents, securities and banknotes in the UV and IR spectral ranges [23]. When using UV radiation, the authenticity of documents is determined by the glow of luminescent dye marks. In the reflected IR radiation, IR images of documents are visualized, changes are detected in them and authenticity is checked. The IR illuminator operates in the spectrum range of 0.8 — 0.95 μm, the UV illuminator — 0.3 — 0.4 μm. The supply voltage of the PK-1 device is = 2 — 2.5 V, weight — 1.2 kg, dimensions 250x110x85 mm.
IR illuminators have been discussed in sufficient detail in [24, 25]. Therefore, it makes sense to focus here only on small-sized UV illuminators. MNPO Spektr has developed small-sized UV illuminators Grif-1, Grif-2, UFO-1, operating in the spectral range of 0.3 – 0.4 µm and using two UV lamps with a radiation power of 9.4 and 4 W each, respectively, with a weight of 3.4; 1.1; 0.5 kg, dimensions of 280x185x165 mm, 286x190x40 mm, 170x30x70 mm, supply voltage of ~220 V 50 Hz, and for UFO-1 – =4 – 5 V [26]. JSC PANATEST has developed the ZB-100F UV lighting system, which creates a UV irradiance of 4000 μW/cm2 at a distance of 325 mm from the illuminator with a lamp power of 100 W and a weight of 7 kg (the lamp itself is 1.3 kg) [27]. All of the above devices contain an image intensifier tube with a UV photocathode based on Cs2Te. An example of such an image converter is the second-generation image intensifier tube from Hamamatsu (Japan) (model V2697U with a photocathode diameter of 18 mm, V3346U with a photocathode diameter of 25 mm, V5180U with a photocathode diameter of 40 mm). The image intensifier has a spectral sensitivity of 20 mA/W at a wavelength of 0.23 µm, a brightness gain of 2.6×103, and a resolution of 40 lines/mm [28].
Thermal imaging equipment is widely used in night photography and video shooting. During its operation, it is possible to take photos from the thermal imaging device indicator screen (LED indicator or TV monitor) or direct video shooting in the IR (thermal) spectrum region. In photo 12The thermal imaging device AGA Thermovision 110 by AGEMA (Sweden) is shown, the LED indicator of which (green glow) is connected to a 35-mm camera using an adapter [28]. The device operates in the spectral range of 3 – 5 µm, has a field of view of 6×120, a geometric resolution of 3 mrad, a temperature resolution of 0.10 C, a range of measured temperatures of (-30) – (+880)0 C, a supply voltage of = 6 V or ~220 V 60 Hz, a weight of 3 kg, and dimensions of 240x140x84 mm. The device is based on a 48-element photodetector based on PbS with thermoelectric cooling (TEC) [28].
Photo 12. Thermal imaging device AGA Thermovision 110,
docked with a 35-mm camera
Thermal imaging device Thermovision 470 from the same company [29] (photo 13) is based on a single-element cadmium-mercury-tellurium (CMT) photodetector operating in the 2–5 µm spectral range. The temperature resolution of the device is 0.20 C at +300 C, power consumption is 30 W, weight is 5.9 kg, dimensions are 154x140x475 mm, the range of measured temperatures is (-20) (+2000)0 C, the field of view angle (depending on the lens) is from 7×70 to 40×400. The built-in 3.5×70; disk drive provides recording on one 3.5×70; diskette. The device allows storing and performing frame-by-frame selection of previously recorded images for the purpose of their analysis or comparison with current images of the same observation object directly in the field. The image processing is provided — both black and white halftone and color in any of the six color sets in order to improve the image quality and their analysis associated with the construction of profiles and histograms. The multi-frame display function supports viewing several thermograms on the screen simultaneously.
Photo 13. Thermovision 470 thermal imaging device
FLIR Systems (USA) offers a range of compact third-generation thermal imaging devices [30 – 32] (photo 14 – 16). Model Therma CAMTM P60 (photo 14) [30] has a field of view of 24×180, geometric resolution of 1.3 mrad, temperature resolution of 0.080 C at +300 C, frame rate of 50/60 Hz. The device is based on an uncooled focal plane microbolometer matrix with a pixel count of 320×240, operating in the spectral range of 7.5 – 13 μm. The device measures temperatures in the range of (-40) – (+2000)0 C with an accuracy of ±20 C. The device weighs 2 kg, dimensions are 100x120x220 mm. The image is displayed on a 4-inch liquid crystal display. The device is powered by =12 V or from a network of ~110/220 V.
Photo 14. Thermal imaging device Therma CAMTM P60
Model Therma CAMTM E2 [31] (photo 15) has a field of view of 25×190, a temperature resolution of 0.120 C at +250 C, and a frame rate of 50/60 Hz. The device is based on the same microbolometer matrix, but with a pixel count of 160×120. The device measures temperatures in the range of (-20) – (+900)0 C with an accuracy of ±20C. The device weighs 0.7 kg, its dimensions are 264x80x105 mm, and it is powered by =12 V. The image is displayed on a 2.5-inch liquid crystal display.
Photo 15. Therma CAMTM E2 thermal imaging device
Model Thermo VisionTM A20 M (V) [32] (photo 16) has a field of view of 25×190, a geometric resolution of 2.7 mrad, and a temperature resolution of 0.120 C. The device is based on an uncooled microbolometer matrix operating in the spectral range of 7.5–13 μm. The device weighs 0.8 kg, its dimensions are 157x75x80 mm, and its power consumption does not exceed 6 W when powered by =12 V. The device measures temperatures within the range of (-20) – (+250)0 C or (+120) – (+900)0 C with an accuracy of ±20 C.
Photo 16. Thermal imaging device Thermo VisionTM A20 M
When using a thermal imaging device with a TV monitor based on a cathode-ray tube, a special attachment to the TV monitor is used to take photographs from its screen, which allows the image to be transmitted to a 35 mm Polaroid camera (photo 17).
Photo 17. Attaching a thermal imaging device to a TV monitor
for taking photographs from the screen
For taking photographs with a conventional camera, you can use standard black-and-white or color film [33] (fig. 3). In case increased sensitivity is required for photographing low-brightness images from the EOP screen, high-sensitivity photographic films can be used [34].
Fig. 3. Graph of dependence of the logarithm of spectral sensitivity
of photographic film (o/e) of different types on wavelength (nm) [33]
Let us now consider a number of issues of optimal matching of photographic film and CCD matrix in spectrum and energy with the screen of an image intensifier tube or TV monitor.
Fig. 4 shows the spectral characteristics of typical image intensifier tube screens, and Fig. 5 their inertial characteristics. Comparison of the curves Fig. 3 and 4 showed that optimal matching in spectrum with photographic film is provided by blue and yellow-green image intensifier tube screens. From the point of view of photographing pulsed light images, the blue screen has an advantage (Fig. 5). The red screen has some advantage in spectrum matching with the matrix of the CCD “Exwave HAD” (Fig. 6) of a digital photo or video camera. However, its light output is significantly lower than that of the other screens mentioned above. In addition, an image intensifier with a red screen is completely unsuitable for direct night vision, since such a screen does not spectrum match the eye. In this regard, such image intensifiers have not become widespread for photo and video shooting. From Fig. 6It follows that a standard image intensifier tube with a yellow-green screen is quite suitable for these purposes. For photo and video shooting from a black-and-white TV monitor screen (Fig. 7), acceptable spectrum matching with a black-and-white film (Fig. 3) and a CCD matrix (Fig. 6) is ensured. There are also no problems with spectrum matching of a color TV monitor screen with a color film (Fig. 8) and a CCD matrix (Fig. 6).
Fig. 4. Curves of dependence of luminous efficiency g (o/e) of image intensifier tube screens on wavelength l (nm) [35]: a – blue (Z-47), b – yellow-green (P-20), c – red (P-25), d – yellow-green (P-43) for “holographic” night vision goggles [39]
Fig. 5. Inertial characteristics of the EOP screens for different durations of light pulses acting on the EOP photocathode [35]: 1 – screen P-20; 2, 3 – screen P-20 and, accordingly, screen P-43 when exposed to continuous light; 4 – screen P-47; a – duration of light pulse tи = 100 ns; b – ti = 1 ms
Fig. 6. Spectral characteristics of CCD matrices: a for a black-and-white TV camera [36], b for a color TV camera [40]
Fig. 7. Spectral characteristics of a white light screen for black-and-white television
Fig. 8. Spectral sensitivity curves of color negative film:
a – blue-sensitive layer,
b – green-sensitive layer,
c – red-sensitive layer [33]
To calculate the required sensitivity S of photographic film according to the diagram Fig. 11, we use the formula:
S = 10 H-1, (1)
where H is the exposure, lx•s.
H = E t, (2)
where E is the film illumination, lx;
t is the exposure time, s.
E = p L top Sin2U’, (3)
where L is the brightness of the image on the film, cd/m2,
tоп is the transmittance of the transfer optics
U’ is half the aperture angle in the image space, deg.
Н = 0.25 p L tоп Гоп-2 О2 t, (4)
where Гоп is the magnification of the transfer optics, times,
О is its relative aperture.
When photographing pulse signals
Н = Еср F-1, (5)
then
Н = 0.25 p Lср tоп Гоп-2 О2 t F-1, (6)
where Eср, Lср are the average illumination and average brightness of the image on the screen, respectively.
Fig. 9. Characteristic curve of black-and-white photographic film, determination of the sensitivity numbers of negative films; D is the light sensitivity, H is the exposure [33]
Fig. 10. Characteristic curves of negative multilayer color photographic material: S is the light sensitivity, L is the photographic latitude [33]
Fig. 11. Scheme for calculating the required film sensitivity when photographing from the screen of the image intensifier tube: 1 – image intensifier tube, 2 – transfer optics, 3 – photographic film, U, U? – half the aperture angle in the object space and in the image space, respectively
In this case, as usual, we use the characteristic curve of the photographic material to enter the normal exposure mode [33].
In practice, there is a problem of photographing a small laser illumination spot on the terrain observed in a night vision device. The optimal exposure on the film for the midpoint of the characteristic curve within the normal exposure is determined by formula (1). From it we find E, given by the value t. Then the brightness of the backlight spot image on the EOP screen is determined by the formula:
where e(l) is the spectral density of radiation of source “A”, o/e,
V(l) is the spectral sensitivity of the eye, o/e,
S(l) is the spectral sensitivity of the film, o/e,
l1, l2 are the spectral working range of the EOP screen, µm.
The brightness L of the spot image on the EOP screen is equal to:
L = L1 + L2 + L3, (8)
where L1, L2, L3 are the brightness of the image spot created by the laser illuminator, the brightness of the image of the terrain, the brightness of the dark background of the EOP, respectively, cd/m2.
L2 = hA E1 Ge-2 p-1, (9)
where hA is the passport value of the EOP conversion coefficient,
Ge is the electron-optical magnification of the EOP, fold.
E1 = 0.25 rф Em Oo2 tо tа, (10)
tа = exp (-aD), (11)
where E1 is the illumination on the photocathode of the image intensifier tube in the backlight spot image, lx,
rф is the background brightness coefficient,
Em is the illumination on the ground, lx,
Оо is the relative aperture of the NVD lens,
tа is the atmospheric transmittance,
a is the radiation attenuation coefficient in the atmosphere, 1/m,
D is the range from the NVD to the backlight spot, m.
L1 = L – (L2 +L3), (12)
E1 = L1 Гэ2 p hА-1, (13)
Knowing E1, we find the required luminous intensity I of the laser illuminator using the formula:
I = 4 D2 Sp E1 exp (aD) (p dвх2 tо)-1, (14)
where Sp is the area of the image on the photocathode of the illumination spot, m2,
dвх is the diameter of the entrance pupil of the lens, m.
These formulas are also valid for video shooting, but then you should tie them to the sensitivity of the CCD matrix.
In conclusion, a few words should be said about photography in several spectral ranges, in particular, in the spectral region of 0.4 – 0.9 μm and 8 – 12.5 μm. The device for work in these spectral regions was created for remote digital aerial photography of ground objects and the underlying surface at any time of the day [36]. Such a small-sized scanning device consists of optical-mechanical, electronic and hardware-software units. The dihedral scanning mirror of the device provided a field of view of up to 1200. In this case, the weight and dimensions of the optical-mechanical unit are equal to 6 kg and Ж200х250 mm, respectively. The power consumption of the device did not exceed 30 W when powered by a voltage of =27 V. The thermal imaging channel contained an 8-element photodetector based on CMT, cooled to 77 K with a specific detection capacity of 4х1010 cm Hz1/2 W-1. The detected temperature difference was 0.1 K. The TV channel was based on a TV camera with a PD3798 CCD matrix with 5348 elements in a line. The hardware and software unit provided shooting modes, processing, recording and displaying in real time of the images being formed and recording additional service information. The operating program of this unit provided joint processing of images from both channels with the construction of a synthesized image in the form of a map of correlation coefficient estimates. Digital images in the visible and IR ranges of the spectrum can be formed in the form of a topographic map tied to coordinates. As a result of testing the device, integrated images were obtained, which in fact represent a map of the area taking into account the information features created in both channels (photo 18).
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Photo 18. Images of the underlying surface obtained using a two-channel device [36]: visible range (a), IR range (b), correlation image – map (c)
Thus, there is a significant number of various devices for night photography and video shooting, providing wide possibilities for various applications.
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