Chapter 2.5 - Digital Photography Flashcards
Since approximately 2010, the acquisition and analysis of digital aerial photographs has virtually replaced what type of film-based methods?
Analog film-based methods
The fundamental differences between digital and film-based photography begin with the use of _____________ instead of ______________ to capture images.
Photosensitive solid state sensors; Silver halide crystals present in film
Typically, digital cameras incorporate a two-dimensional array of silicon semiconductors consisting either of which detectors?
Charge-coupled device (CCD) or Complementary metal-oxide semiconductor (CMOS)
Which part of the sensor array senses the energy radiating from one pixel in the image field?
Detector or photosite location
What is produced when the energy strikes the surface of the detector?
Small electrical charge
After the small electrical charge is produced, the magnitude of the charge becomes ____________ to the scene brightness within the pixel
Proportional
The charge is converted to a voltage value, which is in turn converted to a digital brightness value. This process results in the creation of ___________ for each photosite pixel in the array.
Digital brightness value
Which is more sensitive to brightness variations from the image field?
A. CCD/CMOS semiconductors
B. Silver halide crystals in film
A. CCD/CMOS semiconductors
The many advantages of digital photography over analog methods begin with:
- Improved sensitivity
- Linearity
- Dynamic range of data capture
These image sensors are monochromatic
CCD and CMOS
To obtain the full-color data of the CCD and CMOS sensors, it is typically covered with what?
Blue, green, or red filter.
Photosites are square, with alternating blue-, green-, and red- sensitive sites arranged in what pattern?
Bayer pattern
In the bayer pattern, how much of the filters are allocated to green, blue, and red?
Blue and red - one-quarter each
Green - one-half
What is the reason for the overweighted allocation of green-sensitive pixels as shown in the bayer pattern?
It takes advantage of the green peak of solar radiation and the increased sensitivity of the human eye to the color green
How much is the typical color depth or quantization level of CCD/CMOS sensors?
Typically 8 to 14 bits (256 to 16,384 gray levels per band)
What is the alternative sensor to the Bayer pattern sensor arrays?
Foveon X3 CMOS sensor
What are the major advantages that digital photography provides relative to analog or film-based photography?
1.Enhanced image capture capabilities;
2. Reduced time and complexity of creating primary data products;
3.Intrinsic compatibility with complementary digital technologies
True of False: Aerial photographs should be taken only by specialized cameras
False. It can be made with virtually any type of camera.
