IMAGE PROCESSING
Presented By :-
Lovely Soni
Chartered Institute of Technology, aburoad.
WHAT IS IMAGE ?Image is an Artifact that reproduce the
likeness of some subjects usually a physical object.
IMAGE ENHANCEMENT Improving Quality of Image Two types of Work Area:
I) Special DomainII)Frequency Domain
In Special Domain enhancement achieved by processing on the actual pixels of image.
In Frequency Domain it is achieved by processing on a frequency or intensity.
HISTOGRAM
HISTOGRAM is graph of color intensity value v/s no. of pixels with that intensity in image.
HISTOGRAM is Blueprint of image. How to construct HISTOGRAM? Working with RGB image of 24 bit image ,
HISTOGRAM is prepared for each color . Working with Grayscale image of 8 bit
maximum 256 shades ,single HISTOGRAM is prepared.
FILTERS FILTERS FOR IMAGE PROCESSING: Brightness Filter Smoothing Filter Noise Reduction Filter Contrast Filter
Brightness Filter To increase BRIGHTNESS of image, move its HISTOGRAM
towards high intensity. It is achieved by adding some fixed value in each pixels
of image. It means HISTOGRAM is shifted by that value and
BRIGHTNESS increased by the same.
BRIGHTNESS FILTER For eg. To increase BRIGHTNESS in RGB image, we have
to add K value in each color that is, RED, GREEN & BLUE. Processed pixel= source pixel + Brightness constant
Brightness Filter
Smoothing Filter To apply SMOOTHNESS, mask of 9 pixels is used
Target pixel
This mask is applied on all pixels to smooth image. To apply this mask we have to move from upper left corner to lower
right corner one by one each pixel. The Target pixel is replaced by the MEAN of mask pixels.
Smoothing Filter
Noise Reduction Filter In image any spike (point or itch) comes during scanning called NOISE. To remove NOISE, in some methods, mask of 5 pixels of “ + “ sign
shape is used. Target pixel
This mask is applied on all pixels of image. Image results in reduced image or low noise image. To apply this mask we have to move this mask from upper left corner of
image to lower right corner one by one on each pixel. The MEDIAN of mask pixels replaces the Target pixel.
Noise Reduction Filter
Contrast Filter To increase CONTRAST of image, spread up its HISTOGRAM over X-axis. It means HISTOGRAM is spread up by a constant value and
CONTRAST increased by the same. For eg. To increase CONTRAST in Gray image, for each pixels , we
have to subtract mid intensity from pixel intensity then increase or decrease it by contrast constant and then add mid intensity value to it.
Processed pixel = (source pixel-128) *(( contrastpercent+100)/100) +128
Contrast Filter
Operations• Euclidean geometry transformation• Color correctness • Digital compositing• Image registration• Image recognition• etc…
Applications• Computer Vision• Face Detection• Feature Detection• Medical Image Processing • Remote Sensing• etc…
Thank You….