ImageWarp supports a variety of image types including all standard Windows bitmaps. Image types differ by the pixel format and the way ImageWarp processes them.
The following table lists the standard Windows types that ImageWarp supports.
Image Type
Bits Per Pixel
1-bit palettized
1
4-bit palettized
4
8-bit palettized
8
16-bi tRGB
16 (5 bits per color)
24-bit RGB
24 (8 bits per color)
32-bit RGB
32 (8 bits per color)
In an RGB image each pixel contains a triplet of values representing the levels of intensity of the red, green and blue colors of light. The number of levels in each color channel depends on the bit depth of an image. When the processing operations are applied to an RGB image, the way in which it will be processed depends on the Processing space option in the Preferences. If the RGB space is selected for processing, an image will be processed in its own space, each color channel to be treated independently. When a different color space is selected for processing, an image will be converted to a selected color space, processed, and then converted back to the RGB type.
Palettized images use the palettes to store color information. Unlike all other image types, the pixel value in a palettized image does not represent a brightness value. Instead, the value within the pixel is an index to an entry in the image's palette. When an entry in the palette is changed, all pixels having the same index will change their color accordingly. The palettes of palettized images can be edited with the Palette Editor. When the image processing functions are applied to palettized images, the images are automatically converted to 24-bit RGB type.
ImageWarp also supports non-standard formats including those with extended pixel depths. Below is the table of the additional image types.
Image Type
Bits Per Pixel
Description
Multiphase
8
256-band palettized image
8-bit grayscale
8
Standard grayscale image
16-bit grayscale
16
High-depth grayscale image
32-bit grayscale
32
High-depth grayscale image
48-bit RGB
48 (16 bits per color)
High-depth color image
Floating point
32
Floating point grayscale image
Complex
64 (32 bits per component)
Floating point complex grayscale image
A standard grayscale image (sometimes referred to as "monochrome") is a subset of the 8-bit palettized type whose palette contains 256 steps of the gray color, ranging from completely black to completely white. When loading an image from a file, ImageWarp identifies a grayscale image by analyzing its palette. If an image is loaded or captured as a grayscale one it will be processed much faster than a palettized image, since no color conversion is involved. You can display a grayscale image in pseudo-color by applying Palette operations to it. ImageWarp will still treat such an image as a grayscale one, processing it in the 8-bit intensity space and transferring the color palette to the resulting images. A pseudo-colored grayscale image can only be saved in the IWD, TIFF, and FITS formats.
A multiphase image is an 8-bit indexed image, each index of which represents a separate class (phase) of objects. Multiphase images are used in logic, morphology and measurement functions They are usually produced from grayscale or true-color images by performing Segmentation in order to separate objects of interest from the background. Multiphase images utilize a special identification palette with steep color differences between adjacent indexes. A special case of the multiphase type is the binary image.
16-bit grayscale, 32-bit grayscale, 48-bit RGB, floating point and complex images represent high-depth formats. The number of pixel levels in these images exceeds the number of gradations supported by conventional video cards. To map the specific levels in such images to the display luminance scale (256 levels), use the Display Range boxes located at the bottom of high-depth image frames.
A complex image is a special type of a floating point image that consist of two components. Each pixel of a complex image is a complex number, i.e. it is represented by two floating point values. If a complex image is in the Cartesian mode, those values will correspond to the real (Re) and imaginary (Im) parts of a pixel. You can picture a complex pixel as a point in a two-dimensional Cartesian plane with the X and Y coordinates equal to the Re and Im components of the pixel. If a complex image is set to the Polar mode, the pair of values for each pixel will correspond to the amplitude (Amp) and phase (Ph) of the complex number. The amplitude equals to the distance between the current point and the origin of the coordinate system and the phase is the angle between the radius-vector of the point and the X-axis. Even though one and the same pixel is defined by different values within the Cartesian (Re, Im) or polar (Àmp, Ph) systems of coordinates, they represent the same point on a number plane. You can switch the mode of a complex image by selecting one of the components you want to display in the Mode box located at the bottom of the complex image frame. If the new mode you selected belongs to a different system of coordinates, the image will be automatically converted to the new system.
An image of a standard or extended type can be converted into another type with the Convert commands. However, you don't have to convert your image into certain types to perform drawing or image-processing operations: ImageWarp can work directly with any image type it supports.
Not all image types can be stored in all formats. Certain image file formats support certain image types. If you save an image into an incompatible file format, ImageWarp will automatically convert the image to the closest image type that matches the selected format. See Image File Formats for more details.
Besides the types listed above, ImageWarp supports the following internal types:
Image Type
Bits Per Pixel
Description
HLS24
24
Standart HLS image
HLS48
48
High-depth HLS image
YIQ24
24
Standart YIQ image
YIQ48
48
High-depth YIQ image
LPRGB32
32
RGB image with luminance channel
LPRGB64
64
High-depth RGB image with luminance channel
ImageWarp uses these internal types in processing functions to perform operations in certain color space. If the color space for processing differs from the input image type, ImageWarp will convert the image to the corresponding internal type, process it and then convert back to the original type. You can select the color space for processing functions in Preferences.
