Telecentric lens

Telecentric lenses allow you to obtain images with less distortion.

I experimented with our telecentric lenses RT3 and RT5.

Telecentric lens RT3, RT5 Attach it to the USB camera. I took a photo of the glass scale.

Photographed with telecentric lens RT3	Photographed with telecentric lens RT5
You can see that there is no distortion in the four corners of the screen. This is the feature of telecentric lenses.

CCTV lens

If you are using a CCTV lens, a telephoto lens will have less distortion than a wide-angle lens.
I experimented with a 6mm fixed focus lens and a 25mm fixed focus lens.

	I attached an 8mm fixed-focus lens to a USB camera and took a picture of graph paper.
	It is evident that the four corners of the graph paper are distorted.

	“I attached a 25mm fixed-focus lens to a USB camera and took a picture of graph paper.”
	There isn’t much distortion observed at the four corners of the graph paper

If it’s a macro lens, some lenses have less distortion depending on their performance, but they tend to be more expensive as a result.

Summary:

Main features of telecentric lenses

1. There is no expansion or contraction of the image within the depth of focus.
→It is possible to reduce measurement errors when measuring dimensions.
2. Less image distortion due to parallax
3. When used in conjunction with coaxial lighting, the brightness of the object is less uneven.
There are two main types of lenses: bilateral telecentric lenses and unilateral telecentric lenses.
We also handle both double-sided and single-sided telecentric lenses.

The characteristics of each are as follows.

Bilateral telecentric lens

A feature of this camera is that the projected size of the subject remains the same regardless of the distance between the camera sensor and the subject.
In other words, by changing the distance on the camera sensor side using a close-up ring, etc., you can change only the distance between the lens and the subject without changing the magnification.
However, the diameter of the lens is physically larger than the area to be projected, so the lower the magnification, the larger the lens size and the higher the price.
Used in precision measuring equipment and projectors.

両側テレセントリックレンズ RT1 RT3 RT5

Unilateral telecentric lens

This lens has a telecentric lens structure only on the subject side.
Unlike a double-sided telecentric lens, when the distance to the camera sensor side changes, the size of the subject will change, just like a non-telecentric lens.
The lens is smaller and less expensive than a double-telecentric lens.
If changing the magnification like a macro zoom lens is not necessary for dimension measurement purposes, it may be used as a fixed magnification replacement.

(In addition to the subject-side telecentric lenses that we handle, there are also image-side telecentric lenses that have a telecentric lens structure only on the camera sensor side.
This is rarely used when photographing workpieces using a regular camera. )

		テレセントリックレンズ（W.D.65mmタイプ）   テレセントリックレンズ（W.D.110mmタイプ）
		テレセントリックレンズ（同軸照明対応・W.D.65mmタイプ）   テレセントリックレンズ（同軸照明対応・W.D.110mmタイプ）
		メガピクセル対応テレセントリックレンズ（W.D.65mmタイプ）   メガピクセル対応テレセントリックレンズ（W.D.110mmタイプ）
		メガピクセル対応テレセントリックレンズ（同軸照明対応・W.D.65mmタイプ）   メガピクセル対応テレセントリックレンズ（同軸照明対応・W.D.110mmタイプ）

Special telecentric lens

■Long distance telecentric lens

A distance of 170 mm can be secured from the tip of the lens to the object.

At this level of magnification, there is not much difference in resolution compared to our zoom lens.

This is effective if you really want to make the lens and camera smaller.

telecentric lens   （Working distance：170ｍｍ）	TG lens + 0.5x auxiliary lens (focal length: 170mm)

■Space-saving, high-magnification telecentric lens

The lens is small and the focal length is short at 40mm, making it convenient for installation in tight spaces.

Although the magnification is high, the resolution is lower compared to our zoom lens.

Space-saving, high-magnification telecentric lens	FZ lens + 2x auxiliary lens
(⇓Enlarge the red frame above)	(⇓Enlarge the red frame above)

2Kigou pitch discrimination and number discrimination are not possible with a telecentric lens.

(Reference) When viewed with our highest resolution lens, it looks like the following.

Summary

The main features of telecentric lenses are

1. Since there is no expansion or contraction of the image within the depth of focus, measurement errors can be reduced when measuring dimensions.
2. Less image distortion due to parallax
3. When used in conjunction with coaxial lighting, the brightness of the object is less uneven.

And so on.

Double-sided telecentric lenses used in precision measurement equipment and projectors.
There are single-sided telecentric lenses, which have a telecentric lens structure only on the subject side.
Double-sided telecentric lenses are large and expensive, while single-sided telecentric lenses are small and relatively inexpensive.

Q: What is back focus

A: Back focus refers to the distance from the rear end of the lens to the focal plane (the imaging sensor of the camera).

If the back focus is misaligned, it will result in a focus shift.

Q: What is flange back?

There can be confusion between flange back and back focus, but they are distinct concepts.

The distance from the camera’s C-mount to the imaging sensor surface (flange back) may vary slightly depending on the camera. Therefore, when changing lenses or cameras, it may be necessary to adjust the back focus.
(We ship products that combine cameras and lenses with precise adjustments.)
Additionally, for lenses with a back focus adjustment mechanism, customers can also make fine adjustments themselves.

We also offer lenses with a back focus adjustment mechanism as optional accessories.

Back focus mechanism lens SDS-M19

For detailed product information, please contact our technical support.

There is an option called the ‘0.5x auxiliary lens’ that approximately doubles the operating distance. (Please note that some models may not have the option of auxiliary lenses available.)

0.5x Auxiliary Lens for Standard Lens: TG-0.5

<Changes in Operating Distance>
* With the optional 0.5x auxiliary lens (TG-0.5) for the standard lens:

When using the 0.5x auxiliary lens, the operating distance becomes longer, and the distance between the lighting and the object also increases. Therefore, it is necessary to use the lighting LED angle (bottom: LED-A2) to fix the lighting near the object.

LED angle（LED-A2）	Mounting Example

If you have any questions, please feel free to contact technical support.”

Chromatic aberration refers to the displacement (color shift) of an image created by a lens due to the wavelength of light. Even when using the same lens, the refractive index of the lens varies depending on the wavelength of light, causing differences in focal length based on color. As a result, when looking through the lens, the position where the image is focused shifts, causing blurring.

In a state where chromatic aberration is occurring: Blue, red, and green light are not focused together, but are dispersed separately.

To mitigate chromatic aberration, there are compound lenses such as achromatic lenses, which are made by bonding several types of lenses together. While using these lenses can minimize chromatic aberration as much as possible, it cannot be completely eliminated.

If you don’t mind sacrificing magnification, use a 0.5x auxiliary lens to increase W.D.

標準レンズ専用0.5倍補助レンズ TG-0.5   <Example> When a 0.5x auxiliary lens is attached to the TG500PC2, the standard 23x to 140x becomes 11x to 70x, and the standard focal length of 90mm increases. Changes to 160mm.

However, in this case, the position of the LED ring light attached to the tip of the lens will be moved away from the object and the light will become dark, so it is necessary to improve the lighting by changing to a higher brightness light or removing the diffuser plate. will become necessary.

	高輝度80灯LEDリング照明 GR-80N2
	With removable diffuser plate

It is possible to change the position of the lighting using the LED angle, but this will interfere with the extended W.D., so use twin arm lighting (SPF-D2), LED spot lighting (SPF-FL3), etc. We recommend.

	Even though I used a 0.5x auxiliary lens to extend the W.D. If you lower the position of the lighting using an LED angle This will interfere with the W.D. that you have worked so hard to develop.
Therefore, we recommend using twin arm lighting (SPF-D2), LED spot lighting (SPF-FL3), etc.
	ツインアームLED照明　SPF-D2   Stationary type dimmable LED twin arm lighting.

Please contact technical support for details.

A lens designed for close-up photography is called a macro lens.
A macro zoom lens is one in which the magnification can be changed continuously and the focal length is constant (does not change).

The following two methods are typical for deepening the depth of field.

(1) Increase the depth of field distance.

(2) Narrow down the optical path *For information on aperture, please refer to “What is depth of focus/depth of field?”

This time I will explain (1).

■ Relationship between depth of field and working distance

Below is a spec table for lenses of the same manufacturer, same series, and same magnification (X4).
The longer the W.D., the deeper the depth of field.

■Actual measurement of depth of field due to differences in working distance

Comparative imaging using lenses from the same manufacturer and series but with differing working distances, observing a glass scale with a 0.2mm pitch tilted at a 45-degree angle and viewed from directly above.

(1) Observation using a lens with an optical magnification of 6x and a working distance of 40mm.

If you determine that the focus is aligned with one increment (0.2mm), then the depth of field can be calculated as 0.2mm x (1/√2) = 0.14mm.

(2) Verification using a lens with an optical magnification of 6x and a working distance of 110mm.

If you determine that the focus is aligned with two increments (0.4mm), then the depth of field can be calculated as 0.4mm x (1/√2) = 0.28mm.

1.What is graphite nodularity rate?

Metal materials are used in all fields, and there are many types of metals.
Appropriate materials must be selected according to the application and purpose.
Cast iron is one of those metal materials.

Cast iron is a composite material in which graphite (nonmetal) is dispersed three-dimensionally within steel.
Depending on which form of graphite exists, mechanical properties such as tensile strength and elongation, and physical properties such as thermal conductivity vary.
In particular, mechanical properties such as tensile strength and elongation require an average graphite spheroidization rate of 80% or more when observed under a microscope (100x magnification).
Therefore, graphite nodularity is an important evaluation criterion to guarantee tensile strength and elongation.

2. Method of graphite nodularity analysis

To analyze the graphite nodularity rate, follow the steps below.

① Pre-treatment process: Rough cutting for large samples
②Pre-treatment process Resin embedding
③Pre-treatment process: Cutting the sample
④Pre-treatment process: Rough polishing of the cut surface
⑤Pre-treatment process Fine polishing of the cut surface
⑥ Pre-treatment process Buff polishing of the cut surface to a mirror finish
⑦ Pre-treatment process Etching treatment with chemicals (burning the surface with chemicals)
⑧ Microscope observation
⑨Classification, counting, calculation

There are many pre-processing steps and it takes a lot of time.
For observation, microscopic observation (100x magnification) is performed using a metallurgical microscope.
“We use classification based on roundness coefficients standardized by JIS industrial standards and numbers based on size.”
These are used to calculate the graphite nodularity rate, such as area calculation and counting.

Calculation of graphite nodularity in microscopic structure
① In principle, the magnification is 100x, and the test is performed on 5 fields of view, and the average value is calculated.
② Graphite and inclusions smaller than 2mm (actual size 20μm) are not covered.
③ Compare and classify with the classification table.
④ Find the ratio (%) of the number of graphite grains with shapes V and VI to the total number of graphite grains and use it as the graphite nodularity rate.
I will do it.
It is an analog method and requires complicated work and is time consuming.
Including the pretreatment process, the work requires a considerable amount of time and effort, is prone to human error, and is difficult to evaluate.

3.Improving the efficiency of graphite nodularity analysis

Therefore, we would like to propose a method using graphite spheroidization software.
This is a method of clearly photographing spherical graphite magnified with a microscope and analyzing it using software.
This is done through image analysis processing according to the calculation method described above.
The image shows graphite spheroidized into various shapes and sizes.
In addition, it is possible to automatically measure the area and count graphite from the high-definition image.
Additionally, still images and accurate values ​​can be output in Excel format, streamlining the entire process leading up to report creation.

Click here for details on graphite nodularity measurement software

黒鉛球状化率測定ソフト（日鉄テクノロジー株式会社製）　KKS04

4. What is the set that can efficiently analyze graphite nodularity rate?

Recommended for those who want to analyze large cast iron, carry it around, and easily measure graphite nodularity!
●Set of small and simple metallurgical microscope (with camera) and graphite nodularity measurement software

小型簡易金属顕微鏡　KKKI-STD6-130DN     Easy to observe large cast iron A small and portable metallurgical microscope

	黒鉛球状化率測定ソフト（日鉄テクノロジー株式会社製）

Recommended for those who want to seriously measure graphite spheroidization rate!

●Set of metallurgical microscope, microscope camera, graphite nodularity measurement software

	倒立型金属顕微鏡 （超高倍率顕微鏡）　GR-29J-C3J
	顕微鏡用USB3.0カメラ（500万画素）　HDCT-500DN3
	黒鉛球状化率測定ソフト（日鉄テクノロジー株式会社製）

5.Summary

It is efficient to use software to measure graphite nodularity.
We have convenient simple sets and full-scale sets available.

Visual inspection from microscope to microscope

Three important points for replacement

①Choose a model with a high frame rate

②Choose a model with good color reproduction

③Choose a model with a wide dynamic range

The recommended model

Fluorescence is a weak amount of light emission and requires a highly sensitive camera.

Therefore, the camera used for fluorescence microscopy is usually a cooled CCD camera (monochrome).

Recently, there is also fluorescence emission in the visible light range, and if there is an amount of fluorescence emission at the visible light level (a level that can be seen with the naked eye), fluorescence observation can be performed with a single color camera.

In that case, there are some things to keep in mind, so please check the following.

・Sensitivity

Sensitivity is the ability to distinguish between noise and signal.

Noise occurs when the original signal cannot be distinguished from the signal emitted by the equipment.

Camera shooting under low light usually produces noise.

There is one more thing, another noise.

Noise occurs during fluorescence observation when “dark current” is generated due to an increase in exposure time.

Dark current is the leakage of electrons during camera exposure, and dark current has the property of doubling for every 7°C rise in temperature.

Sensor temperature has a large effect on dark current, but especially when shooting under low light and the exposure time is long, it can lead to a decline in the signal-to-noise ratio and image quality.

To prevent this, the camera usually has to be cooled. Therefore, a cooled CCD is used.

However, depending on the fluorescence conditions, this may not be necessary.

Generally, cooled CCD cameras are often expensive, and as long as the fluorescence reaction is strong enough, there is no problem even if the camera is forced to cool using a fan or Peltier device.

・Check wavelength sensitivity

Is the camera sensitive to fluorescence wavelength?

Light has wavelengths, and we need a camera sensor that can detect the fluorescent wavelengths. Although it depends on the conditions, fluorescence emission is generally a very weak amount of light.

First, we need to make sure that the camera can detect and is sensitive to that fluorescence wavelength.

You can tell whether a camera has a sensitivity characteristic by looking at its spectral sensitivity characteristic diagram.

・dynamic range

A camera sensor converts light into a signal with a “dynamic range” (the ratio of the maximum to minimum required amount of charge), which determines the camera’s light detection performance.

・Is the camera sensor CCD or CMOS?

Although CCD sensors are still installed in high-end cameras, they are becoming less common due to the rise of CMOS sensors.

In particular, recent CMOS sensors have almost the same performance as CCD sensors in terms of cost, number of pixels, speed, noise, power consumption, etc., so I don’t think you need to worry about that.

・Is the shutter method global shutter or rolling shutter?

CCD sensors only have a global shutter method.

For CMOS sensors, you can choose between global shutter method and rolling shutter method.

If the subject is moving, this difference in shutter method will greatly affect the image quality.

Rolling shutter has poor ability to follow movement. This method sequentially exposes each sensor row at a time, so if the subject moves, the image will be distorted.

On the other hand, global shutter has good ability to follow movement. This is because the sensor is exposed all at once, so there is no difference in exposure time.

However, if you are photographing while the object is still under microscope observation, there is often no problem with the rolling shutter method.

・Monochrome camera or color camera?

For general fluorescence observation, monochrome cameras are preferred due to their high sensitivity.

Color cameras have lower sensitivity than monochrome cameras. The cause is the Bayer filter.

This filter is necessary to capture the color information of the image, but it only allows light of certain wavelengths to pass through, reducing the amount of incoming light.

Furthermore, the use of an IR cut filter in front of the camera sensor that cuts out infrared light is another factor contributing to the decrease in sensitivity.

Therefore, when analyzing coexisting molecules using multiple fluorescent substances, it is generally necessary to combine light sources and filters according to their respective excitation and fluorescence wavelengths, and to take images with multiple monochrome cameras.

Recently, there is also fluorescence emission in the visible light range, and as long as the amount of fluorescence emission is at the visible light level (a level that can be seen with the naked eye), fluorescence observation is often performed with a single color camera.

・Number of pixels

You can choose a camera with the number of pixels that suits your purpose.

If you want to shoot with a high pixel count, you tend to choose a camera with a high pixel count, but if you have a high pixel count, the sensor size (number of sensor inches) will generally be larger, making it more likely that vignetting will occur when taking pictures with a microscope. Caution is required.

Therefore, it is necessary to select a camera with the optimal number of pixels that suits the purpose and microscope.

・Summary

A cooled CCD is not absolutely necessary for fluorescence photography.

There is also fluorescence emission in the visible light range, and if the amount of fluorescence emission is at the visible light level (a level that can be seen with the naked eye), fluorescence observation is often performed with a single color camera.

Although we do not handle cooled CCD cameras, we do have color cameras that emit fluorescent light in the visible light range, and that emit fluorescent light at the visible light level (a level that can be seen with the naked eye).

Please see below for product details.

1. What is pretreatment for observing and measuring metal structure?

Pretreatment is required to observe the metallographic structure using a microscope.
Broadly speaking, the following four types of pretreatment are common.

2. Each pretreatment method

①Sample cutting
A large sample specimen is cut into small pieces using a cutting machine.

②Resin embedding
The cut sample is hardened with resin.

The reasons and purposes for embedding it in resin are as follows.

・Maintenance of sample edge shape
・Holds the shape of the sample so that it does not deform.
・Create a flat shape that is easy to observe

<Representative resins>

·acrylic resin
・Bakelite resin
·Epoxy resin
・Melamine resin

Each resin has different properties and colors, as well as different curing methods.
There are various types such as thermoplastic, thermosetting, natural curing, UV light irradiation curing, and two-component mixture curing.

The sample is placed in a cylindrical case and hardened with resin.
For heat curing, use a heating embedder, and for UV light curing, use UV light.

It may be omitted depending on the observation target.

③ Grinding and Mirror Finishing

The surface of the metal sample specimen is polished.
Generally, a grinding machine is used.
There are manual and automatic types of grinding machines, with the former being suitable for experts and the latter for beginners.
The manual type is prone to uneven polishing due to the force applied by hand to hold the sample, making it suitable for experts.
The automatic type, when the sample specimen is fixed to the sample fixing fixture, automatically polishes it, making it less prone to uneven polishing and suitable for beginners.

Rough polishing to precision polishing of the sample specimen is done using waterproof abrasive paper.
Polishing is done in wet conditions (while dripping water) from coarse to fine.
In precision polishing, the sample is finished to a mirror surface using cloth or buff polishing, diamond slurry, alumina powder, etc.
Therefore, it is necessary to change the grit of the waterproof abrasive paper many times.
There are single-layer and double-layer types of grinding machines, with the double-layer type being more expensive but convenient.

Once the mirror surface is achieved, the specimen surface is washed with flowing water.
After washing, it is dried using a dryer or similar equipment.

④ Etching Treatment (Surface Corrosion)

The polished surface of the sample specimen is immersed in etching solution (corrosive solution) suitable for the material and properties of the sample.
Etching treatment is performed for a duration that corresponds to the concentration of the etching solution and the material and properties of the sample specimen.

Example: For graphite spheroidization, a 3% nitric acid alcohol solution (Nital solution) is used.

After etching, rinse the sample specimen with water to remove the etching solution, then clean with ethyl alcohol or similar solvent before drying with a dryer or similar equipment.

3. Microscopic observation of metal structure

After undergoing the aforementioned pre-treatment processes, the metal structure can finally be observed. The polished mirror surface of properly pre-treated sample specimens is observed under a microscope. By enlarging the structure and adjusting the focus, the metal structure is observed.

At our company, we offer “metal microscopes,” “microscope USB cameras,” and “sets combining metal microscopes and cameras.” Please refer to the following for product details.

However, for advanced measurements such as observing non-metallic inclusions, measuring graphite spheroidization rates, and analyzing grain sizes (ferrite grain size, austenite grain size), specific measurement methods and counting techniques are utilized.

Observing metal structures requires appropriate pre-treatment processes, which can be time-consuming and labor-intensive. Therefore, it is recommended to efficiently perform these tasks in a shorter time frame using dedicated software.

Shodensha’s low-cost high-speed camera achieves filming at up to 1000 frames per second, all for just around 200,000 yen. We offer both monochrome and color options, both at the same price.

There’s often a misconception that if color is available, monochrome isn’t necessary. However, monochrome cameras have their own advantages. Firstly, since they don’t use RGB, their sensitivity is exceptionally high. They can even capture footage at 800 frames per second under fluorescent lighting (although flickering may occur depending on the type of fluorescent light). Additionally, monochrome footage has smaller file sizes compared to color, allowing for longer recording times.

If you absolutely need to determine the color of the subject, then color is necessary. However, if color isn’t particularly important, monochrome is recommended.

Furthermore, traditional high-speed cameras required storing footage in the camera’s internal memory, which limited recording time. Our new cameras don’t have built-in memory; instead, they use the computer’s memory for recording. This means that the more memory your computer has, the longer you can record. Additionally, we offer optional long-duration recording software, allowing for recording by the minute or hour.

We also offer demo units for lending, so if you’re interested, please don’t hesitate to contact us anytime.

Khi xem xét về việc ghi video trong thời gian dài bằng camera tốc độ cao, có hoặc không có bộ đệm trên máy ảnh sẽ quyết định nhiều.

camera tốc độ cao CHU130-EX của Matsuden có bộ nhớ ghi video tích hợp dung lượng 2GB.

Trong trường hợp camera tốc độ cao không có bộ đệm, hình ảnh từ máy ảnh sẽ được ghi trực tiếp vào RAM (Bộ nhớ) của PC, và sau đó sẽ được lưu trữ trên HDD hoặc ổ SSD.

Tóm lại, khả năng ghi video trong thời gian dài phụ thuộc vào sự cân bằng giữa dung lượng RAM của máy tính và tốc độ ghi của ổ HDD.

Nếu tốc độ ghi vào HDD chậm, bộ nhớ có thể bị tràn.

Đối với các giải pháp, bạn có thể:

– Tăng dung lượng RAM trên máy tính.
– Sử dụng ổ SSD thay vì HDD.
– Để ý rằng, việc thử nghiệm cùng với máy tính là cần thiết để đánh giá thực tế.

Thông tin thêm, về việc ghi video với độ phân giải 130 vạn điểm ảnh (1280×1024) trong 15 phút sẽ tạo ra một tập tin có dung lượng 120GB.

When recording for extended periods like 24 hours, using a hard disk recorder with a video microscope makes it straightforward to achieve long-duration recordings.

For example, with a 2TB (terabyte) hard disk, you can record for more than 10 days continuously.

The terminals compatible with attaching to the hard disk include BNC connectors as well.

It is also possible to convert the video terminal to USB and directly save the video to a PC. In this case, as a guideline, the file size will be approximately 1MB per second for VGA (640×480) resolution. Therefore, you will need to prepare an HDD or SSD with a capacity that accommodates the required recording time. We can also assist you with recommendations for suitable hard drives. Please feel free to contact our technical support for assistance.