FAQ: GigE Vision 関連
Q: GigE Visionカメラにはどんなケーブルが必要ですか ?A: Cat5eも使えますが、Cat6を推奨します
Q: GigE Visionを使った場合、トリガの遅延が発生しますか?A: 遅延を避けるためにはハードウエアトリガをご利用ください。JAIのGigE VisionカメラはHirose12ピンコネクタからハードウェアトリガの入力が可能です。
Q: カメラは何台接続可能ですか?A: 理論的には無限です。とは言え実際に接続されるカメラの数は、伝送されるデータレートによって制限されます。伝送データレートは撮像される映像の解像度とフレーム数の乗数から計算できます。1秒に伝送できるデータレートは最大125Mバイトです。
Q:GigE Visionカメラ用スイッチャの仕様に制限はありますか? A: スイッチャを使う場合にはGigE Vision用をご利用ください。また、ジャンボパケットを使う場合スイッチャは1.5kbパケット以上の伝送能力が必要です。
Q: ジャンボパケットとは何ですか?A: Ethernetデータパケットが1440kバイトを越える場合ジャンボパケットと称されます。ジャンボパケットを使うとオーバーヘッド（packet headers）が減る分データ伝送能力が改善されます。
Q: JAIはカメラ用にソフトウエアも供給するのですか?A: はい、供給します。JAIはカメラ用にWinXP対応のドライバとDLLファイルを開発しました。また、SDK（Software Development Kit）の開発も完了しています。SDKを使うことでJAIのカメラを使用したシステムの開発が容易になります。
Q: GenICam（ジェニカム）とは何ですか?A: GenICamはGigE Vision規格を準拠し、XMLファイルを使って接続されたカメラのインターフェイスを容易にします。
Q: XMLファイルとは何ですか?A: 個々のカメラの機能をシステム内で有効にするために使われる標準ファイルフォーマットです。XMLファイルはカメラに内蔵され、カメラがホストコンピュータに接続されるとコンピュータにダウンロードされます。ダウンロードされたXMLファイルはホストコンピュータのソフトウエアにより自動認識され、個々のカメラの機能を使える環境が整います。
FAQ: General questions
Q: How do I get HD/VD output from Analog cameras? A: This can be done by internal SW setting, please consult the user's manual.
A: Unlike the CV-M10BX/RS, the CV-M10SX does not support an interlaced mode. It is therefore not possible to view the image on a video monitor.
Q: Does JAI manufacture cameras for infrared light? A: The EXview sensor used in CV-M50IR is sensitive in the near infrared and therefore useful using artificial light with a high amount of infrared light. In general, CCD sensors are sensitive to near infrared light and can be used for e.g. surveillance. JAI Camera Solutions does not make cameras sensitive to mid- and far infrared light.
A: No. You need to use the WEN pulse (pin no.: 6) on the 6 pin Hirose plug.
Q: How can I control the long time exposure in analogoutput cameras? A: By applying external VD pulses. The exposure time is the time span between two VD pulses. It is recommended that the maximum exposure time of two seconds is not exceeded.
A: By synchronizing the trigger pulse to HD.
Q: What is the minimum and maximum duration for the trigger signal? A: A trigger pulse greater than one HD (i.e. 64 µsec.), with a maximum duration of 1 msec can be applied to the camera.
Q: What is the minimum and maximum duration for the trigger signal? A: A trigger pulse greater than 2µsec., with a maximum duration of 1msec can be applied to the camera
Q: How do I get access to the pixel clock output? A: This can be done by internal jumper setting, please consult the user manual.
A: In principle the delay can be long, but it is recommended not to exceed two seconds. The stored image is distorted by the "dark current" image caused by leakage in the pixels.
A: Some cameras have a separate video output signal, which can be used directly for controlling an external auto iris lens system. For other cameras, a modification is needed either internally or externally. Please note that this will only work in continuous mode. Make sure to buffer this output, as it may otherwise affect the overall image quality.
A: For most JAI cameras the IR-cut filter is mounted in a filter ring. This filter ring is mounted in the C-mount thread of the camera.
A: Normally interlaced cameras (TV-standard) will only allow one field to be captured when triggered. It is, however, possible to capture both fields in trigger mode when a strobe light (LED flash, Xenon flash) is used as illumination. The shutter must be set to OFF, and the camera set to frame mode. Contact JAI for an application note on how to operate in this mode.
A: Yes. There are eight pre-defined steps from 2-16 fields (1 field equals: EIA: 1/60 sec., CCIR: 1/50 sec.). This only works in continuous mode.
A: An RGB camera provides 3 primary colors on three different channels, thus no information is lost. The result is superior color reproduction at full resolution.
A: Quite simply, progressive scan means that the picture information is accumulated simultaneously and then output line-by-line or sequentially. The result is a non-interlace image with full vertical and horizontal resolution captured in a single rapid shutter event.Traditional interlace CCD cameras are only capable of capturing one field, or half the vertical information, per shutter event because the scan function breaks the integration period into two sequential field scans. In dynamic image capture, by the time the second field of information is stored and scanned the subject already has moved. The result is a ghosting or blurring effect once the two scan periods are combined to create the whole, interlaced picture. Interlaced images of even static objects can introduce some noticeable "jitter". This is successfully eliminated with progressive scanning.
A: A multiple shutter function allows multiple exposures within the same image frame. It can be used for studies of very fast movements. The multiple exposures are done by adding the charge from triggered accumulations into the stopped vertical CCD register. After last exposure the resulting image with multiple exposures on top of each other is read out.
A: "An IR-cut filter is a color filter blocking the infrared light. There are several good reasons for using an IR-cut filter. All JAI color camera include an IR-cut filter in order to achieve proper white balance and realistic colors. Monochrome cameras are sometimes equipped with an IR-cut filter, to block out unwanted energy from light sources inclucing longer wavelengths (typically above 600 nm). Such light sources may be halogen tungsten lamps or even the sun. Reducing the IR contents in monochrome cameras helps improve the MTF (Modulation Transfer Function) which results in sharper images, allowing cameras to visualize finer detail."
A: If the accumulation starts immediately on the leading edge of the trigger without any delay, it is called asynchronous accumulation.
A: Binning is a read-out method where the charge from more adjacent pixels are added together and read out as a single pixel. In horizontal binning adjacent pixels in the same line are added together. In vertical binning adjacent pixels in the same column are added together. In some JAI cameras, a combination of both is used. The advantage of binning is a higher read-out frame rate, and a higher sensitivity. With both H and V binning, the image aspect ratio is correct. The resolution for a two-to-one binning will be 50%.
A: Frame-delayed readout makes it possible to make a triggered accumulation and delay the resulting image readout. A trigger pulse will initiate the accumulation, and an externally applied VD will start the readout. It can be useful in applications with more cameras triggered at different time and readout at the same time. Or if more cameras are triggered at the same time, and the resulting images are read out in sequence to a single input frame grabber.
A: If the accumulation in triggered mode does not start immediately at the trigger leading edge, but starts at the first HD pulse hereafter, it is called H synchronized accumulation. If the trigger and HD are not synchronized, a delay (or jitter) of < =1H can be expected
A: Smear is caused by an unwanted charge build-up in the CCD vertical registers during the time before the actual shutter time and during the readout time. In smearless mode the smear level can be reduced, if the CCD is read out with a high speed just before the actual triggered shutter time. It will reduce the smear effect above the highlighted areas. Below there is no reduction. In smearless mode, the trigger will start this dummy readout before the accumulation starts, causing a small delay.
A: In analogue cameras a limited bandwidth and propagation delay can cause a reduction in the image quality. It is not sure that the content from a sensor pixel is placed in the display byte without any cross talk from the adjacent pixels. In a digital camera the contents from the sensor pixels are transferred to the display bytes without any distortion.
A: When talking about 3CCD cameras, "chromatic shading" generally means unequal color reproduction from top to bottom. Please use a F-number higher than 4.0. Furthermore, avoid using high shutter speeds (i.e., short shutter times).
A: For these C-mount cameras the X, Y axis direction is < ±0.1mm (i.e. the center of the sensor in relation to the center of the C-mount).
A: With internal synchronization the delay can be up to one HD.
A: Use only lenses specially designed for 1/3" 3CCD cameras. Please contact your local dealer.
A: As the video output is AC coupled, a random video output will cause a difference between the fields if the connected systems lack DC-restoration. The output can be modified to DC output. Please contact JAI.
A: Partial scan is a readout mode, whereby only a part of the CCD is read out. The remaining lines are "fast dumped" out of the image sensor and ignored. This results in a higher frame rate, with reduced vertical resolution. Typically, partial scan is defined as 1/2, 1/4, 1/3, 1/8, etc. of the full resolution, located in the middle of the imager. Some camera models have user selectable start position and number of lines in partial scan. CMOS imagers also allow partial scan, where a region of interest can be defined both in the vertical and horizontal direction. This is normally referred to as windowing.
A: This is the definition of modes of operation, whereby the readout (scanning) of the image sensor deviates from the standard operation. Examples of readout modes are "binning", "partial scan", "frame-delay readout", "readout inhibit"
A: Use the search function of the web site. E.g. type in an image sensor, for instance ICX285, and all cameras built around this imager will be listed.
A: Smear refers to an unwanted artefact in the image, showing up as a vertical stripe (vertical streak) from the top down to the bottom of the image, emanating from the bright parts of the image. The reason for smear in interline transfer CCD sensors is the scattering of light into the vertical shift register during the readout phase. Shorter shutter times make smear more obvious. Using strobed light sources can eliminate smear, so that no light is hitting the image sensor during readout. Implementing special readout modes can reduce smear.
A: Under conditions where a CCD is exposed to very strong light, the storage capacity of the pixels may be exhausted and subsequently become saturated. The excess charge that cannot be held within the pixel spills over to neighbouring pixels. When bloomed, bright spots in the image show up as completely white blobs.
Q: What is PIV (P.I.V.)?A: PIV stands for Particle Image Velocimetry. It is a technique for measuring and recording instantaneous velocity vectors in a cross-section of a flow. Two velocity components are measured. By using a stereoscopic approach all three velocity components can be recorded, which results in 3D velocity vectors for the whole area. CCD cameras capable of capturing two images with extremely short inter-frame time (in the range of a few microseconds). Used together with specialized computer tools, the images result in real-time velocity maps.
A: The so called flange focal distance is 17.526 mm for C-mount lenses. This is the distance from the reference shoulder to the CCD image sensor surface. The actual distance from the last lens element to the CCD varies depending on lens design and focal distance.
A: All network switches designed for Gigabit Ethernet can be used. When using Jumbo packets, make sure to use a switch that can handle more than 1.5kB packets