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  1. Stanislav

    Camera positioning sugestions

    Fast reverse gear:) It is good illustration of uneducated designers who trust in your approach "easy intuitive design" with "easy to use simplified 3D design software” you promote. Their projects look glamorous with girls and boys but make laugh and angry installers in the field. It is also good illustration that inspection on real place is obligatory. Design software is an auxiliary tool. Project quality depends on designer skill and work. It is very good illustration of your approach, Maxim.
  2. Good way to find the best positions for your cameras is modeling in special CCTV design software. You should draw your building in 3D quickly and roughly without detailing. But you must keep accurate dimensions. It will not take much time. Then you should place cameras at possible places, enter camera heights and basic camera parameters: Lens focal length, Image sensor format, Resolution in pixels on horizontal and vertical. After these actions you will be able to play with cameras, change places and camera parameters and see 3D models of images from your cameras. Thus you will select cameras and position fit your needs. In this way you can achieve better result than by following advices from other persons who did not visit your place. Real dimensions are great important. Your pictures can not contain all dimentions. Other persons have not information you have. Any demo version from VideoCAD Starter to VideoCAD Lite will be suitable. You can use demo versions for free within 30 days. VideoCAD Professional demo version is not suitable for such tasks. Professional version allows much more but its demo version has considerable restriction (it does not allow to change lens focal length). VideoCAD Professional is intended for professional using. VideoCAD Lite demo version is good free choice for such amateur tasks.
  3. IVk-RgLR0jI
  4. Today, all Lens calculators and CCTV design software (except VideoCAD Professional 8.1) calculate view angles of wide angle lenses with errors, because they do not take into account the Lens distortion. About Lens Distortion Additional errors are expected in calculating the view angles of modern cameras because of the image sensor size is considered in inches from the time of vidicons not taking into account existence of the modern image sensors with aspect ratios different from 4:3 and/or using not whole pixel area for scanning. See Specifying active area size of the image sensor
  5. What do you think about such Fields of view? What lens calculator can calculate them correctly?
  6. Stanislav

    Fisheye Camera Coverage

    VideoCAD 8 Professional can simulate panoramic cameras. See details http://cctvcad.com/videocad_help/index.html?prim_fisheye.htm You can also model wide-angle cameras with strong lens distortion. See Modeling lens distortion
  7. Here is an idea of choosing frame rates based on the desired frequency of getting in the frame objects with the known positions and velocity. http://cctvcad.com/videocad_help/index.html?prim20_framerate.htm
  8. Thank you, MaxIcon Here are several images for better understanding sharpening. Level of one line from the images is shown as a curve. Normal image with a little noise. No blurring and no sharpening. Pay attention on vertical curve without overshots at the line drop point. Blurring. Line at the drop point is not vertical. Any lens has limited resolution. If the lens resolution is unsufficient, it adds blurring. But lens blurring doesn't reduce noise because of the noise is added on the image sensor. Little oversharpening. Line at the drop point is strictly vertical as on the normal image. But overshots appear. There is optimal sharpening level which can correct lens blur and approximate normal image. It allows manufacturers to use cheaper lenses. Images with little oversharpening look better. But sharpening as any other image processing can't restore detail lost because of limited lens resolution, it can make images which will look like a normal image but this corrected image will not contain all details. Pay attention also on increased noise level in comparison with normal image. It is unnoticeable on image but it is visible on line curve. Noisy image without sharpening. The same noisy image with the same little oversharpening. With noisy image oversharpening corrupts it. To prevent this effect, many cameras turn off sharpening automatically when the image becomes noisy.
  9. Noise reduction and sharpening are not contrary each other. They are different procedures. There are a lot of noise reduction algorithms including 3D noise reduction. It is not simple blurring, but image blurring is a side effect of NR. General advantage of NR inside camera is traffic reduction in low light conditions. Sharpening is image processing which can correct low resolution of lens in some degree. But noise increasing is a side effect of sharpening. Thus you should try to use sharpening if you use a lens with not enough resolution in good light conditions. But you should not use sharpening with low light noise images. It makes the image more noise. If your camera works in low light condition, using noise reduction can decrease traffic and disk space requirements. In case of limited bandwidth or disk space using noise reduction can increase image quality in whole.
  10. Here is expected difference between f=2.8mm/F2.0 and f=.3.6mm/F1.8 in low light. When the light is sufficient there will be no difference in contrast and noise. f=2.8mm/F2.0 f=.3.6mm/F1.8
  11. Stanislav

    IP Video System Design Tool Pro

    Cheaper tool with less capabilities - VideoCAD Starter ($85) Cheaper tool with more capabilities - VideoCAD Starter II KIt ($198)
  12. Stanislav

    More light?

    Please see my article Illumination and camera sensitivity in CCTV. Therein is some information how these images are simulated. *IR illuminators can be modeled too.
  13. Stanislav

    camera placement help please

    You need not a tester. Just download VideoCAD Starter, you can use it for free in 30 days and model your situation in details. There is a full free software - CCTV Design Lens Calculator, it can help you too.
  14. Stanislav

    More light?

    The difference between F1.2 and F1.4 depends of current light level and camera sensitivity. If there is a bright region on the scene then current camera exposure can be limited by this region and changing lens will not improve image at all. If the scene is low illuminated uniformly, you can expect theoretically difference as shown on the images. But real difference can be a little more because varifocal lens probably transmits less light than equivalent fixed F1.4, it has more complicated construction and more optical losses than fixed lens. Also the F1.4 value in varifocal lens spec F1.4, 3.5-8mm can be applied to 3.5mm focal length. With 8mm focal length the F number can be worse.
  15. Of course I should write "The thinner your cable is - the more its resistance " Thank you for this correction. Thinner cables have worse quality and less price. They have more losses in hight frequences, than thick cables. Actually thin cables have more losses in direct current too, but in hight frequences their losses are much more. Thin cables have worse amplitude-frequency characteristic. Not exact. Loss in high frequance is caused by resistance too. "Shunt capacitance per unit length, in farads per metre." and "Series inductance per unit length, in henrys per metre" don't lead to losses. These parameters determine "Characteristic impedance in ohms (Ω).". Losses are caused by "Series resistance per unit length, in ohms per metre" and "Shunt conductance per unit length, in siemens per metre.". "Series resistance per unit length, in ohms per metre- The resistance per unit length is just the resistance of inner conductor and the shield at low frequencies. At higher frequencies, skin effect increases the effective resistance by confining the conduction to a thin layer of each conductor." "Shunt conductance per unit length, in siemens per metre. The shunt conductance is usually very small because insulators with good dielectric properties are used (a very low loss tangent). At high frequencies, a dielectric can have a significant resistive loss." See details: http://en.wikipedia.org/wiki/Coaxial_cable#Fundamental_electrical_parameters Thus the Series resistance and Shunt conductance are raised on hight frequences. Because of thinner cables have more "Series resistance per unit length" and "Shunt conductance per unit length" than thick cables, they have more losses in high frequences.