Naked truth about the IR cameras

Probably everybody, who deals with monitoring, has noticed in the last few years the noticeable increase in offers for cameras with infrared illuminators.

There are cameras, called "day/night", with two converters. The cameras called "dual", that is reacting for the visible light and the infrared radiation. The cameras with mechanical infrared filters. The cameras with built-in LED illuminators, often called IR diodes.

The interest in infrared cameras results from the simple fact, that the monitoring is often required during bight, when there is the natural visible light shortage, required for the normal cameras operation. The possibility of watching in such conditions, using the infrared waves, is very tempting. It does not matter, that the image qulaity is significantly worse. The user assumes, that it is better to see the object in worse quality, than not to see it at all.

Buying the camera with built-in illuminator and lens we have the psychic comfort, that the responsibility for selection of three elements: camera converter, lens and IR illuminator is born by the producer, and we do not have to think about the illuminators vawe length, or if the particular lens has the infrared filter or not.

We also hope, that the diodes lighting angle is correctly selected for the lens viewing angle.

The variety of types, offered by almost every producer, may make everyone feel dizzy. To compare them, we look at the declared technical para,eters, and the small consternation takes place. The sensitivity of all cameras is given as 0 lux.

The converter sensitivity for the visible light is given very rarely.

The 0 lux parameter is however true, because in zero scene lighting (by the visible light), we have in the camera the visible image, lighted by the infrared light. So how can we compare the cameras with the same converter? The image quality depends in such cases either on the very converter sensitivity, as well as on the illuminator power.

Some producers give the number of installed LED diodes. Of course it has nothing to do with the image quality, as there are diodes with various power of emitted light.

But now here comes something in the camera technical parameters - the mysterious "range" parameter (expressed in meters).

Let's think, what range are we talking about. There is no such parameter in technical standards. It cannot be the maximum distance of the camera observation, because we can direct it to the moon and observe that great celestial body, so the range would equal thousands of kilometers. We may guess, that it is the range of illuminator, installed in the camera.

We may assume, that it is the distance, in which in the darkness the image with the vision signal quality 100, 50, or 30 IRE has been achieved. Here comes the question, what value it is, at what signal to noise ratio, and what scene reflection coefficient? (It is doubtful, that the tests have been performed in perfectly white room, and it is the basis of "range")

We may only guess, that it is the range in the room, as the infrared light dispersion outside is several times bigger. Very rarely the enigmatic range outside the building is given.

The modern marketing (not only for the cameras) consists in such technical data clouding, that the customer cannot compare them, so he relies on the producer opinion, who of course recognizes his own product as the best.

None of the producers of tested cameras placed the measurement conditions in the catalogue sheet.

So how that "range" has been measured? When trying to answer, many questions appear, regarding the range definition. If the camera has the range of 5 m, it does not mean, that the illuminator radiation ends in that distance. Most of the radiation decreases with the distance square, and may be detected with the infrared detector in the distance tens times bigger.

By intuition, the range would rather mean the ability to recognize the object in the distance of 5 m in total darkness. But here comes the question, what object is it, and on what background it is viewed.

To tell the truth, in our considerations and speculations about the mysterious "range" definition we are wandering in darkness. But let's go further, maybe there is some light at the end of the tunnel.

As most of the cameras are used in the monitoring, which in turn is most often directed to human or vehicle monitoring (rarely the production process), we may assume, that we are talking about the distance, in which we can see the human body. (It is doubtful, that it would be the vehicle visibility assessment)

So, using the elimination, we have come to the conclusion, that it is probably the human body observation. Here comes the next question. What are the conditions of observation, and is it the face recognition, or the presence detection, e.g. any intruder in the camera visual field? As far as in the interphones the face recognition may take place, in the wide angle cameras (most of the cameras with infrared illuminators) the face recognition is rather impossible. We can only presume, that it is the distance, in which we can detect the person, lighted by the built-in diodes. In such conditions the best results would of course be obtained for the big Negro, moving in front of white wall. We, however, have gone another way.

Because naitger in literature, nor in Internet there are no information, regarding the IR cameras, we have decided to make the first, timid step in that direction.

The basic advantage and purpose of such test is that all cameras will be tested in the same conditions. It does not matter, if the test room will have the scene reflection coefficient 0.5 or 0.8, wahat matters, is that all cameras will be tested in identical environment, which allows for comparing them with each other.

But first, a few words about the test conditions.

For the test purposes we have prepared few test screens.

One of them is the panoramic screen with the approximate dimensions 315x80 cm, hanged about 180 cm above the ground, and placed on the circle with diameter of 2 m. The camera is placed on the tripod in the middle of that circle, and directed to the screen centre, which allows for visual angle and the infrared radiation uniformity measurement.

The central location of the camera causes, that the light emitted by the diodes returns to the lens at the same angle, and is less dispersed, than in case of flat screen.

The panoramic screen dimensions allowed for testing the cameras with the angle up to 90⁰, which was enough. The 2 m radius allows also for the focus adjustment assessment, as for such distance all cameras had the depth of focus (or it was possible to adjust it).

Other measurement screens are the male body outline in the natural size, 180 cm high, located in the distance of 4, 6, 8, 10 and 12 m from the camera.

Under each silhouettes there are large digits in A4 format, informing about the screen distance from the camera. For the higher contrast the screens have been placed on the black background.

In the presented results the backgound has been removed, to compare the measurement screens only.

The test field arrangement and dimensions are shown below.

To compare the quality of each camera, we have made two screen dumps for each camera, using the laptop and built-in capturing card. One of them is the image directed to the panoramic screen, where we can say, if the illuminator angle equals the camera viewing angle. The second dump is the camera directed to the male silhouette screen, located 8 m from the tripod. Both directions are marked with red colour. The screens are located as close to each other as possible, but they do not mask each other. Such arrangement has caused, that the angle between left screen (12 m) nad right screen (4 m) equals 23 degrees. As most of lenses have the angle bigger than 23⁰, almost each screen dump included all screens.

The distances, declared by the producers, were of course larger than 12 m (the further screen, due to our technical conditions), but the image quality in 12 m is great for showing the possibilities of particular cameras.

The tests included several cameras, and the results are presented below in the alphabetical order with the short comment.

To enlarge the screen dump to the natural size just click the image.

B3622 camera	The B3622 camera has rather good illuminator, but the disqualifying element is the shade, put on the camera. We have tested three, randomly selected cameras, and unfortunately in each one the quality is definitely impaired after putting on the shade. Another negative element is the infrared light penetration into the camera. After putting on the shade the internal electronics reflection is visible. The camera without the shade operates correctly. During the day, when the LED diodes are turned off, the image with the shade is rather correct.
	Some shades were so badly manufactured, that the camera image was totally out of focus.

C-3132/IRD camera	The range of 15 m, given by the producer, is rather doubtful. Practically, in the dstance of 12 m the human silhouette distinguishing was impossible.

C-3134/IRD camera	This camera is slightly better than C-3132/IRD, however the given range of 30 m is strongly exaggerated.

C-3532/IRD camera	This camera was slightly better in the tests than smilar C-3132/IRD and C-3134/IRD, probably because it has the 6 mm lens, so the smaller visual angle. The LED diodes give definitely more uniform illumination for this lens.

Grand-IP camera	The illuminator in this camera is for the marketing purposes only. The panoramic screen (2 m distance) is almost invisible, and the male silhouette screens are totally invisible. We may assume, that the camera located next to the computer would see the human face during the night in 1 m distance, e.g. during the teleconference. But there is the question, if there are teleconferences, which take place in total darkness? We must admit, that in the daylight the camera had the correct image for its quality.

IRD-2330L camera	We must admit, that as for the camera with the wide viewing angle, it has rather uniform lighting and quite high power of emitted light.

IRD-2331L camera	Similarly as the IRD-2330L camera, it has the same illuminator, and the image from the cameras in this price range is really good.

SG-678HC/IRD camera	In spite of narrow viewing angle (4.3mm for ¼") the declared range of 15 m is rather doubtful.

SN-IR141DC camera	The wide angle camera with not too strong illuminator, however the test screens quality was good.

WPH-2320L camera	The camera with very uniform lighting. However, there would be some trouble with the declared 15-20 meters.

WPH-2331L camera	Very strong illuminator as for the camera of this class. With the wide angle of 720 the image may be consider good.

YC-27/IRD camera	The camera with good infrared illuminator. The low number of diodes (20) is characterized with strong radiation emission. Very narrow rays angle makes use of wide ange lenses impossible. Below we present the measurements, performed with 8 mm and 16 mm lenses. Due to dimensions of our room it was not possible to test the declared range of 60 m, but the quality of image, achieved in our conditions, allows to count this camera as the "long range" device.
	View for the camera with 8 mm lens. View for the camera with 16mm lens.

YC-28U/IRD camera	Among the tested cameras the YC-28U/IRD definitely takes the first place. The camera has the viewing angle adjustment in range from 250 to 600. Very well selected high power illuminator has covered the extreme lens settings. We award it the first place.

This was the end of our tests. I think that the presented results will help You in getting familiar with the infrared cameras subject, and will contribute in better equipment selection during the night monitoring system designing.

NEW CAMERAS MODELS:

C-3393/IRD camera	The camera equipped with variable focal length lens, from 3.9 mm to 85.8 mm. The visual field ranges from 50o to 2o.

C-3338/IRD-3 camera	The camera equipped with variable focal length lens, from 3,5mm to 8mm. The visual field ranges from 54o to 25o. Very good solution with the focal length and lens focus change. The IR illuminator very well selected for the lens. Very low current consumption (160mA)! No power supply unit included.

C-3131S/IRD camera	Small camera, but equipped with the infrared illuminator of rather good range. The camera is fully hermetic.

CC-400S/IRD-2DC camera	Quite interesting illuminator solution allows to select any lens with the automatic iris for vary good SONY converter. Such solution allows for achieving great image at night, even with rather weak, built-in illuminator.

CC-403/IRD-1 camera	Practcally the cheaptest camera with infrared illuminator on the market. It is quite good for the few meters of observation.

CC-403S/IRD-2 camera	The most willingly bought camera for the indoor observation. The wide viewing angle has very important role.

CC-508S/IRD-6 camera	Very good illuminator with long range and wide angle. The SONY converter with high resolution gives really good image. We honesty recommend it.

CC-606S/IRD-4 camera	The camera with resolution of 520 lines and the approximate illuminator range 50 m. The rather wide viewing angle deserves attention, it equals approximately 45°, which decides of its universal use. Another advantage is durable, metal housing and small dimensions.

CCD-406S/IRD-2 camera	Attractive price as for the camera with SONY converter and infrared illuminator.

DP-950C/IRD camera	Easy visual field change due to mobile head. Lower infrared illuminator range, than declared by the producer.

CCM-5025S/IRD-8 camera	Miltary camera, which has no competitors on the market. It is the best camera for uses outside the buildings. Fantastic illuminator with long range and wide angle. The high resolution SONY converter gives very good image during the day and at night. High weight. Below we present the authentic screen dumps from the construction site observation, made from the same place with two different cameras. The first one is the ordinary colour TC-3804/01A1 camera. The second one is CCM-5025S/IRD-8.
TC-3804/01A1 CCM-5025S/IRD-8 No focus in the left photo is caused by too short distance between the camera and the test screen (2 m) in relation with the used lens (focal length 25 mm).	CCM-5025S/IRD-8 CCM-5025S/IRD-8

CCM-5025S/IRD-10 camera	Fantastic illuminator with long range, but we must admit, that its angle is quite narrow, which is visible in the photos. The SONY converter with high resolution gives very good image. High weight.
No focus in the left photo is caused by too short distance between the camera and the test screen (2 m) in relation with the used lens (focal length 25 mm).

CCM-5099MAFS/IRD-8M camera	The camera equipped with variable focal length lens, from 3.9 mm to 85.8 mm. The visual field ranges from 47o to 3o. Easy visual field change due to mobile head. Lower infrared illuminator range, than declared by the producer.

CCM-6099S/IRD-5 camera	The camera equipped with variable focal length lens, from 5mm to 50mm. The visual field ranges from 51o to 5o. Durable manufacturing, possibility of many camera parameters modification. Very durable wall bracket. Great zoom in the lens and the best SONY converter, used in the industrial cameras. The lens focal length and focus adjustmet requires the protective glass disassembly.

The current procedure for testing the infrared cameras is a little different. The test results are placed directly with product description on its website at http://shop.delta.poznan.pl.