Please Note: This blog post is part of a series of five posts altogether.
The posts include: Part 1, Part 2, Part 3, Part 4 and Part 5.

Introduction

The quality of an image is determined by many things: Illumination, lens and camera parameters. In the following text, we are going to take a look at how to set camera parameters for optimal image quality.

Shutter (Exposure Time)

The shutter determines the CCD‘s exposure time. It may be adjusted manually or automatically. The three first sample images show a key ring (the LED is initially off) with correct exposure time, one which is too short and another which is too long:

Switching on the LED, the image is overexposed in such a way that it only shows a big, white spot. The LED is correctly represented, if we decrease the exposure time. There is, however, a vertical line which disturbs the image. This is a typical CCD problem and is known as “smear”. To avoid this, we close the diaphragm and increase the exposure time:

(To be continued…)

I am delighted to announce that we have just published the following press release:

Bremen, (July 10, 2008) - The Imaging Source - a multi-national manufacturer of industrial cameras - has just announced a new series of cost effective LED lighting modules, which seamlessly integrate with The Imaging Source USB, FireWire and GigE camera.

• Very bright LEDs
• Direct connection to the camera
• All parameters can be set via the shipped software, IC Capture and IC Imaging Control or by custom built software
• Compatible with The Imaging Source USB CCD cameras
• Compatible with The Imaging Source FireWire cameras
• Compatible with The Imaging Source GigE cameras

All cameras manufactured by The Imaging Source ship with IC Capture and IC Imaging Control. The former is an end-user application, with which it is possible to set all cameras parameters, save singular images and image sequences and display live video streams. IC Imaging Control is an SDK, which consists of a .NET component, ActiveX control and C++ class library for Windows XP and Windows Vista.

Please do not hesitate to contact us for more information.

I am very happy to announce that we have been able to dramatically reduce the price of most of our cameras, which ship with a 1024×768 resolution.

For more details, please take a look at the products’ web site:

• FireWire and USB 2.0 Cameras

Please do not hesitate to contact us, if you would like a quotation for any of the above cameras, or indeed, would like to talk to us about any matter related to image processing or machine vision.

Please Note: This blog post is part of a series of five posts altogether.
The posts include: Part 1, Part 2, Part 3, Part 4 and Part 5.

Typical mistakes

The bewildering variety of optical components, as well as “historical legacy issues” originating from the world of picture tubes, lead to different mistakes when selecting these components. In the following you will find the three most basic misunderstandings:

Incorrect: The lens format and the camera format have to be identical.
Correct: The lens format should preferably be larger than the CCD format since optical flaws appear at the rim of the lens.

Incorrect: If the lens format is larger than the CCD format it has to have a larger/smaller focal length.
Correct: The focal length exclusively depends on the CCD format, the working distance and the
object size.

Incorrect: Extension rings increase/decrease the depth of field.
Correct: Extension rings decrease the minimal working distance.

Fixing blurred images

There are two basic reasons for blurred images:
• The lens quality is lower than the quality of modern CCD chips. The Pentax M Series recommended in this white paper has been especially designed to work with modern CCD chips. Wide-angle lenses, however, have weaknesses due to their construction.
• The lens setup is incorrectly arranged. This usually leads to extremely blurred images. In such cases please proceed as follows:

C Mount lens / CS Mount camera:
Please check whether a 5 mm extension ring has been screwed between the camera and the lens. The Imaging Source exclusively manufactures CS mount cameras. Each of the cameras is shipped with a 5 mm extension ring.

CS Mount lens / CS Mount camera:
If you have accidentally screwed a 5 mm extension ring between the camera and the lens, you will only be able to focus on close objects.

CS Mount lens / C Mount camera:
This configuration only allows to focus on very close objects. If this is not your aim, then you have to use a CS mount camera. The Imaging Source exclusively manufactures CS mount cameras.

“Sticking” extension rings:
If you previously have used the camera or the lens with a thin extension ring, it often “sticks” to either of them. In such cases you are not able to focus to infinity for no apparent reason.

(The End.)

Our Japanese reseller Argo exhibited at the Vision Show (Spring 2008) in Yokohama, Japan last week. Below are some photos of the event and in particular of their stand: