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Chasys Draw IES Help:


Scanner & Camera
 

Introduction

To acquire images from an imaging device such as a digital camera or scanner, use the Scan / Acquire option under the File > Devices and More menu. The application will show a dialog box where you can select the device to use:

Chasys Draw IES will then attempt to acquire an image from the device, displaying dialog boxes with options if and when necessary. Just follow the prompts. Below is a sample "Scan" dialog:

NB: "HP DeskJet" is a trademark of Hewlett Packard , which is in no way affiliated to or endorsed by John Paul Chacha's Lab.

 

Choosing Devices

For imaging devices, go for the high end. A 14 mega-pixel camera will produce better images than a 5 mega-pixel camera, and a VGA camera will be insufficient for most purposes. The same goes for scanners, if you can get a 2400 PPI model, go for it. You'll hardly ever use a photo or scanned image the way it is, you'll almost always end up cropping and rotating it. You'll lose some quality in the process, which is why you need the extra pixels.

Generally, you'll need a higher resolution for your camera than your scanner, the reason being that the "pixels" quoted by the manufacturers are usually not full pixels as such. Most digital cameras use a color filter mask over the light sensor matrix (Charge-Coupled Device or CMOS sensor). The most popular pattern is the Bayer mask though other patterns are also used (e.g. the RGBE mask). In the Bayer mask, each square of four pixels has one filtered red, one blue, and two green (the human eye is more sensitive to green than either red or blue). The result of this is that luminance information is collected at every pixel, but the color resolution is lower than the luminance resolution.

Bayer Filter Matrix
RGBE Filter Matrix

Secondly, the JPEG/EXIF formats used by digital cameras are lossy - they achieve image compression by throwing away some of the information. Your eyes tend not to notice a lot of things, which allows us to throw away a lot without you noticing it's missing. Exactly how much is thrown away depends on the JPEG encoder settings. Furthermore, most digital cameras use digital zoom, which works by reducing the area of the CCD (Charge-Coupled Device) used in image capture, hence the number of pixels used. A scanner, on the other hand, uses a line sensor instead of a matrix, and gives you the option of transferring image data to your image editor directly without any loss, therefore you'll only need crazy resolutions if you are scanning small items like projector slides.

 

Camera Phones

When cameras first started appearing on mobile phones, they were mostly seen as toys, and nobody took them seriously. However, with the coming of multi-mega-pixel phones, they've now become very popular, and it is now common to have hundreds of phone-shots on one's hard-disk. 12 mega-pixel cameras have started appearing on phones, and will soon become very popular. When that happens, the usual (read amateur) digital camera market will suffer a serious reorganization.

Cameras on phones tend to have very small apertures (out of necessity - size is always an issue with phones), therefore they tend to pick up a lot of noise, especially in poor lighting. Due to processing constraints, artifacts like blocking are also common. However, because this is an ever-growing segment of the digital photography industry (I must admit that I have a camera phone, and yes, I have hundreds of photos taken with it), it has now become necessary to include it in the world of image editing, and Chasys Draw IES Artist isn't lagging behind - I have effects targeted at this segment of the market, and the super-resolution feature will undoubtedly be very popular here.

That said, I still insist that a 6 mega-pixel dedicated digital camera will out-perform a 12 mega-pixel camera phone on any day. If your intention is to get the best possible quality, get a dedicated digital camera, preferably a professional-class dSLR.

 

Best practices

To get the most out of your digital imagery, you need to know how to get quality - and how to retain it. Sticking to these golden rules should keep you ahead of the game:

  Avoid JPEG if you can. JPEG saves space, but it destroys detail.
  Scan images from within Chasys Draw IES Artist. Don't scan images to intermediate files using the scanner software.
  Work at reasonable resolutions. Too much will prevent you from working efficiently, too little will get you nowhere (3~9 mega-pixels for A4 will do).
  Invest in image capture devices of a reasonable quality. A 1200ppi scanner should suffice for most applications, and a 12 mega-pixel camera is a good compromise for general use.
  Where possible, take multiple shots and merge them using super-resolution.
  Avoid resizing images unnecessarily. Any resize, be it an expansion or reduction, degrades the image somewhat.

 

Copyright © John Paul Chacha, 2001-2017

Opinions expressed here are the personal opinions of the author and/or other parties and neither bear legal weight nor indicate the future plans, direction or intention of John Paul Chacha's Lab, which is free to adopt any technologies criticized here.