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The specifications of C mount camera always include “image size” and “image sensor size”.

In addition, this size is the value needed to calculate the field of view (when selecting the lens).

(To calculation of field of view, please refer to “f value of lens”.)

 

 

The use of “image sensor size”

 

 

You can also calculate the size of one pixel.

For example: The image sensor of 1 / 2.5 inch of 1.3 million pixels (1280 X 1024) is:

Horizontal  5.6 mm / 1280 pixels = 0.0044 mm / dot

Vertical    4.2 mm / 1024 pixels = 0.0041 mm / dot.

 

Image Sensor Size Meaning

 

Typically, when referring to monitor sizes, it indicates the diagonal length. However, the size of an image sensor is not measured diagonally.

For instance, in the case of a previously mentioned 1/2.5-inch sensor with 1.3 megapixels, the horizontal dimension is 5.6mm and the vertical is 4.2mm, resulting in a diagonal length of approximately 7mm.

 

However, the actual 1/2.5-inch sensor measures 10.16mm diagonally. This discrepancy originates from the historical representation of imaging tubes using vacuum tubes, where the size indication was based on the diameter of these tubes. Consequently, the size representation of image sensors has been aligned with this convention.

 

The Actual image sensor size 

 

 

 

 

 

 

 

The practical use of imaging sensor size

The actual utilization of imaging sensor size pertains to the selection of the requisite lens and the calculation of the distance to the subject.

 

(1) In the case of CCTV lenses (fixed focal length lenses)

 

We shall calculate the required lens based on the desired dimensions of the subject to be captured. At this juncture, the essential factors are the “imaging sensor size of the camera” and the “distance to the subject (W.D.).”

 

 

 

 

 

If we aim to ensure a vertical field of view of 300mm at a distance (W.D.) of 1 meter, what focal length lens should be selected? Assuming the use of a 1/2-inch camera sensor, the dimensions are as follows:

Imaging sensor size for a 1/2-inch camera:

 

 

 

The formula for the f-value is as follows:

f-value = (Distance to the subject (mm) × Vertical size of the imaging sensor (mm)) / Vertical field of view

By substituting the values:

f-value = (1000mm × 4.8mm) / 300mm = 16mm

By selecting a lens with a focal length of 16mm, the desired vertical field of view can be achieved.

The calculation for the horizontal field of view can be done in a similar manner.

By the way, if either the vertical or horizontal field of view is known, the other can be easily calculated without additional computations.

For a square-shaped imaging sensor with a 4:3 aspect ratio, as in this case, the horizontal field of view would be 300mm × 4/3 = 400mm.

 

(2) In the case of macro lenses 

In the case of macro lenses used for capturing magnified images of subjects, the focal length is typically predetermined. In such instances, the f-value alone does not adequately represent the lens characteristics. Instead, the optical magnification is used as a measure.

For macro lenses, the optical magnification expresses the desired level of enlargement. With a lens at 1x (1:1 magnification), the observed field of view matches the size of the imaging sensor.

For example:
– For a 1/3-inch sensor, the dimensions are 4.8mm × 3.6mm.
– For a 1/2-inch sensor, the dimensions are 6.4mm × 4.8mm.

Considering these specifications, I recommend referring to our company’s macro lens specification sheet for more detailed information.

 

 

 

Additionally, when using a macro lens, the imaging sensor size is also utilized in calculating the overall magnification (the final magnification displayed on the monitor). The imaging sensor size plays a crucial role in determining the effective magnification of the captured image.

 

For more detailed information, I recommend referring to the concept of magnification in microscopes, as mentioned in the “Concept of Magnification in Microscopes” resource.

 

USB Camera CS series	USB Camera DN series	GigE Camera
1/1.1 inch	CS1200-GC（12MP・color） ／ CS1200-GB（12MP・monochrome）		EG1200-GC（12MP・monochrome）／ EG1200-GB（12MP・monochrome）
1/1.7 inch	CS1200-C（12MP・color） ／ CS1200-B（12MP・monochrome）		EG1200-C（12MP・color） ／ EG1200-B（12MP・monochrome）
1/1.8 inch		DN3RG-130（1.3MP・color） ／ DN3RG-130BU（1.3MP monochrome）   DN3RG-200（2MP color ） ／ DN3RG-200BU 2MP – monochrome	EG320-C（3.2MP color） ／ EG320-B（3.2MP monochrome）   EG600U-C（6MP color）／ EG600U-B（6MP monochrome）
1/2.3 inch		DN3R-1000（10MP color）
1/2.5 inch	CS500-C（5MP color） ／ CS500-B（5MP monochrome ）	DN3R-500（5MP color）
1/2.9 inch	CS41-C（0,04MP・color） ／ CS41-B（0,04MP・monochrome）		EG41-C（0,04MP・color） ／ EG41-B（0,04MP・monochrome）
1/2 inch	CS130U-C（1,3MP・color） ／ CS130U-B（1,3MP・monochrome）   CS500U-GC（5MP・color） ／ CS500U-GB（5MP・monochrome）		EG130U-C（1,3MP・color） ／ EG130-B（1,3MP・monochrome）
1 inch	CS2000-C（20MP・color） ／ CS2000-B（20MP・monochrome）		EG2000-C（20MP・color） ／ EG2000-B（20MP・monochrome）
2/3 inch			EG501-C（5MP・color） ／ EG500-B（5MP・monochrome）

Summary:

The imaging sensor size is a crucial value required for calculations such as “field of view” and “lens selection.” In the case of CCTV lenses, the f-value can be computed as follows to determine a lens that can achieve the desired vertical field of view:

f-value = (distance to the subject (mm) × vertical size of the imaging sensor (mm)) / vertical field of view.

For macro lenses, the imaging sensor size is utilized in calculating the overall magnification (the final magnification displayed on the monitor).

 

The phenomenon of flickering” refers to irregularities observed in footage captured by a camera, such as “repeated variations in brightness” and “shifts in color tone,” which are not perceptible to the naked eye.

In this article, we will provide an overview of “flickering phenomenon” and discuss methods to prevent it.

 

(1) WHAT IS FLICKERING?

 

 

The phenomenon known as “flickering” occurs with certain lighting devices that either flicker in sync with the power frequency or pulse in a dimming system.

Although the human eye cannot perceive the flickering of light, when the camera’s shutter speed is faster than the frequency of the flicker, it results in irregularities in the captured footage, such as “repeated variations in brightness” and “shifts in color tone.” This is referred to as the flickering phenomenon.

Flickering occurs under lighting conditions that involve periodic flashes, such as fluorescent lights, while it does not occur with direct current lighting.

There are two types of symptoms associated with flickering phenomenon:

1. In cameras with a global shutter, the entire image experiences cyclic changes in brightness.
2. In cameras with a rolling shutter, the image exhibits horizontal stripes of brightness variations, and these stripes may appear to flow vertically.

 

 

The phenomenon of “flickering” in cameras with a rolling shutter results in the appearance of horizontal stripes of brightness variations. 

 

 

 

 

Methods to prevent the phenomenon of flickering can be categorized into three primary approaches:

1. Utilize lighting devices employing direct current illumination.
2. Adjust the shutter speed to a pace slower than the flicker frequency.
3. Employ a camera equipped with the “flicker-free feature.”

 

 

1. Utilize lighting devices employing direct current illumination.

Flickering occurs in the presence of lighting sources that exhibit periodic emissions, while it does not occur when using lighting fixtures that operate on direct current illumination.

2. Adjust the shutter speed to a pace slower than the flicker frequency. 

 

The phenomenon of flickering can be somewhat mitigated by adjusting the exposure time or shutter speed settings of the camera, but it cannot be completely eliminated.

Even if it appears to have disappeared, there are still variations in brightness occurring at intervals of several tens of seconds or longer.

In particular, when capturing images with a high-speed camera under fluorescent lighting, significant flickering phenomena occur.

* If it is not possible to adjust the shutter speed on the camera, one can compensate for the reduced illumination by narrowing the aperture of the lens and using lighting fixtures with direct current illumination. This helps to comparatively reduce the impact of pulse lighting.

 

 

3. Employ a camera equipped with the “flicker-free feature.”

 

 The “flicker-free feature” enables the camera to automatically detect the flickering of the light source and capture images at optimal moments with minimal impact on brightness and color tones.

To avoid flickering phenomena, it is recommended to use lighting for high-speed cameras that either operate on direct current illumination or synchronize with the camera shutter, such as strobe lighting.

At our company, we offer a range of products including high-speed cameras, lighting specifically designed for high-speed cameras, and strobe lighting. If you are experiencing difficulties with flickering phenomena, please don’t hesitate to contact us for assistance.

Resolution means a numerical value indicating of pixels in a bitmap image. It is the fineness of the grid that expresses the image and it is represented how many pixels are divided in 1 inch.

For microscope, each camera, lens and monitor has different resolution.

1. Cameras and lens resolution are the detail of grid that represents the image.

It is a term that expresses the details of objects (screen, printed result, photographic film, etc.) that can define the size of the physical image.

Therefore, the physical resolution means the minimum unit that can be distinguished from the image (pixel, in the case of a printing result or photographic film, a line / space where the image can be resolved by a resolution chart) is determined per unit length of the object. It is expressed by the number that can be included and represents the definition level not the total number.

Camera and len resolution is very important in selecting resolution.

For example: If camera resolution is high and lens resolution is low, the image will be poor in resolution. Please be careful

2. What is monitor resolution?

Have a look at this. “about monitor resolution“

We will also select cameras and lenses. Please feel free to contact our Technical Advisor.

GigE camera is connected by LAN port.

However, there is no power supply line in LAN port attached to normal PC.

(Of course, power is necessary to operate the camera.)

 

There are two ways to use GigE camera.

1. Prepare individual separate power supply for camera.

2. Prepare NIC for PoE (Power over Ethernet) interface (LAN port with power supply line).

1.

There is no problem if an AC adapter is attached to the camera. But in order to connect between PC and camera, power support equipment is very necessary. It is called PoE injector. It can be obtained easily around 10,000 yen. It is possible to purchase with PC peripherals manufacturer (Elecom, Sanwa Supply, Buffalo etc.).

2.

NIC is short of Network interface card. NIC has the same meaning as the LAN board and indicates an expansion board. As mentioned above, there is no power supply line in the standard LAN port of a normal PC. Therefore, you need to add such an expansion board (card) to the PC.

 

When taking pictures by the camera, there are some cases which the part is too bright (halation / overexposed), and the part is too dark (blackened).

Dynamic range is called the range of contrast difference (defense range) which can be concealed at the same time to the edge before the halation (white jump) from black collapse (too dark to nothing). The unit is db (decibel).

The larger dynamic range number, the better camera.

However, when comparing human eyes and cameras, naked eyes are superior even with excellent cameras.

For example, even if you can see it with naked eyes, shooting with a camera may cause halation (white overexposure) or may not be visible.

It is a technique to express a wider dynamic range than normal image.

Reducing the contrast of the original image with large contrast and take a wide dynamic range.

Even with images with differences in brightness and darkness, it is possible to reduce blackout and whiteout.

The following is an excerpt from cameras specifications made by other companies, but WDR (wide dynamic range) has the same function.

 

There is what is called a dynamic range in the camera vocabulary. The dynamic range is the range of the brightest part and the dark part that the imaging element can feel.

 

If it exceeds this range on the bright side, it becomes halation (white jump).

The screen becomes black when exceeding this range in the dark.

 

HDR and WDR are functions that widen this range and reduce the difference between bright and dark areas. It is used for remove halation.

(However, if you use this function, the contrast will be lowered.)

 

For example: If you shoot a picture with differences in light and darkness, it will be like the picture below.

 

Normal function shooting	HDR function shooting

 

Our HDTV camera has HDR function.

By applying this, you can shoot images with reduced halation.

(It is an effect of widening the dynamic range. Although it does not make infinite, it can not be removed completely)

 

Normal function shooting	HDR function shooting
Normal function shooting	HDR function shooting

 

If this HDR function is combined with a filter and V character block, the performance will be further improved.

<HDR function + polarization filter>

<HDR function + White V character block (background)>

The size of the imaging element written in the specification etc. is not the actual diagonal dimension in notation following the “tube diameter” of the imaging tube age.

For example, 1/2 inch CCD means 「A CCD with the same image size as the image size produced by a 1/2-inch imaging tube」

However, the size will be confirmed with this notation.

If it is a 4: 3 elements, the size will be identified as below.

“CCD Camera image size”

GigE camera is short of Gigabit Ethernet camera.

Expensive dedicated board is not required, general-purpose Ethernet cable can be used for the cable.

The connection port is also LAN port.

However, a power supply for driving the camera is necessary. (See “LAN port connecting GigE camera”)

 

 

 

 

 

The cable can be extended up to 100 m.

Because it is cheap and can communicate at high speed, it is a user-friendly camera that can construct an inexpensive image processing system.

 

The price is equivalent to USB cameras, but the feature of this product is the ability to extend the cable up to 100 meters. Additionally, it offers stable communication.

 

The initial setup (environment configuration) is slightly more complex than USB cameras, but once connected, the communication stability surpasses that of USB.

 

Cマウントカメラの仕様書にはかならず、「イメージサイズ」、「撮像素子サイズ」が記載されています。
同じレンズを装着した場合、素子サイズが小さい方が視野が狭くなります。
また、このサイズは、視野の計算（レンズの選択）時に必要な値となります。
（視野の計算方法は「レンズのｆ値」を御参照ください。）

1画素のサイズもこれで計算できます。
例えば、130万画素（1280 X 1024）の1/2.5インチの撮像素子であれば
水平方向　　5.6mm／1280画素＝0.0044mm/dot
垂直方向　　4.2mm／1024画素＝0.0041mm/dot　　　となります。

ちなみに、レンズ側の仕様書にも、「1/2インチカメラ対応」等の記載があります。
この場合、「1/2インチカメラだけに対応している」という意味ではなく、「1/2インチ以下のカメラならば使える」という意味です。
但し、上にも記載したとおり、視野は変わってしまいます。

弊社が主に使っている　　1/2インチ、1/2.5インチ、1/3インチ　撮像素子のサイズは下記の通りです。

不思議なことに気が付きませんか？
例えば1/2インチ素子の場合、対角が8mmになっています。
1/2インチは12.7mmであるにも関わらず8mmです。
これは撮像素子の特殊な事情で、撮像管時代の基準がそのまま使われているためです。

S-Mount với kích thước nhỏ và giá thành thấp.

There is no regulation of flange back.

S-mount are used for compact cameras and board cameras. Currently, there are many lenses with small size and low price.

（例）

 

S → C mount conversion ring is also on sale.

 

C mount has provisions of flange back, whereas S mount does not have flange back specification.

Therefore, even if the aperture is changed, It doesn’t mean that C mount lenses can be used.

When using the C mount lens, I think that it is necessary to try it.