Lesson 2 Flashcards
(44 cards)
What is a digital image composed of?
A large array of discrete dots called pixels.
What is the neighborhood of a pixel?
The pixels surrounding a given pixel.
What does greater spatial resolution mean?
More pixels are used to display images.
How can you halve the size of an image?
By taking out every other row and every other column.
What is the purpose of the preprocessing step in digital image processing?
To correct defects and enhance contrast for better feature analysis.
What are the three different color models mentioned?
- RGB color model
- CMYK color model
- HSV color model
What is a point operation in image processing?
Applying a simple function y=f(x) to each gray value in the image.
What is the formula for calculating grayscale pixel value in scikit-image?
Y = 0.2125R + 0.7154G + 0.0721B.
What is the significance of the weights used in grayscale conversion?
They better represent human perception of red, green, and blue.
What are the effects of poor technical image quality?
- Low contrast
- Noise
- Blurring
- Aliasing
What does top-1 accuracy refer to?
Accuracy by comparing the top prediction with the correct class.
What types of noise can degrade an image signal?
- Salt and pepper noise
- Gaussian noise
- Speckle noise
What is aliasing in images?
Occurs when a signal is sampled at slightly less than the period of the original signal.
What does image enhancement aim to achieve?
To make the result more suitable for a specific application.
What are the two main domains for image enhancement?
- Spatial Domain
- Frequency Domain
What is histogram equalization?
Mapping a roughly equal number of pixels to each intensity level for a flat histogram.
What is Otsu’s Method used for?
To determine the optimal threshold for separating background and foreground pixels.
What is adaptive thresholding?
Calculating local thresholds with fixed block size surrounding each pixel.
What type of intensity transformation can improve image appearance?
Gamma transformations.
What is the effect of contrast stretching?
Improves the appearance of images for better segmentation and recognition.
What is the function of a grayscale image to binary image conversion?
A pixel becomes white if its gray level is greater than T, black if less than or equal to T.
What is the purpose of smoothing in image processing?
To reduce noise and improve image quality.
What are the two types of blurs mentioned?
- Motion Blur
- Out of focus Blur
What is the formula for contrast stretching?
Using percentiles to rescale intensity within a specified range.