Practical aspects of adjusting digital cameras.
This chapter introduces the adjustment of digital camera settings using the tools found within image acquisition software and discusses measuring gray-level information such as (1) the histogram, (2) line scan, and (3) other strategies. The pixel values in an image can be measured within many image capture software programs in two ways. The first is a histogram of pixel gray values and the second is a line-scan plot across a selectable axis of the image. Understanding how to evaluate the information presented by these tools is critical to properly adjusting the camera to maximize the image contrast without losing grayscale information. This chapter discusses the 0-255 grayscale resolution of an 8-bit camera; however, the concepts are the same for cameras of any bit depth. This chapter also describes camera settings, such as exposure time, offset, and gain, and the steps for contrast stretching such as setting the exposure time, adjusting offset and gain, and camera versus image display controls.
Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
Joshua J
JJ
Nordberg
Greenfield
G
Sluder
D000818:Animals; D002478:Cells, Cultured; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D008853:Microscopy / Q000295:instrumentation / Q000379:methods; D010781:Photography / Q000295:instrumentation / Q000379:methods*; D012984:Software
Differential interference contrast; Digital cameras; Gray-level information; Histogram; Line-scan plot