@thi.ng/pixel-analysis/hues.d.ts

Image color & feature analysis utilities

import type { ReadonlyVec } from "@thi.ng/vectors";
import type { TemperatureResult } from "./api.js";
/**
 * Iterator consuming HSV colors and only yielding those matching given hue
 * range and minimum saturation (all normalized in [0,1] range).
 *
 * @remarks
 * If given a pixel buffer as input, it MUST be in `FLOAT_HSVA` format.
 *
 * If `minHue` is greater than `maxHue`, the range will be interpreted to wrap
 * around at 1. E.g. the range `[0.8, 0.2]` selects hues >= 0.8 and hues
 * < 0.2.
 *
 * @param colors
 * @param minHue
 * @param maxHue
 * @param minSat
 */
export declare function selectHueRange(colors: Iterable<ReadonlyVec>, minHue: number, maxHue: number, minSat: number): Generator<ReadonlyVec, void, unknown>;
/**
 * Similar to {@link selectHueRange}, but only yields indices/IDs of matching
 * colors.
 *
 * @remarks
 * See {@link selectHueRange} for details about hue ranges.
 *
 * @param colors
 * @param minHue
 * @param maxHue
 * @param minSat
 */
export declare function selectHueRangeIDs(colors: Iterable<ReadonlyVec>, minHue: number, maxHue: number, minSat: number): Generator<number, void, unknown>;
/**
 * Similar to {@link selectHueRange}, but only returns a count of inputs
 * matching given hue range and minimum saturation (all normalized in [0,1]
 * range).
 *
 * @remarks
 * See {@link selectHueRange} for details about hue ranges.
 *
 * @param colors
 * @param minHue
 * @param maxHue
 * @param minSat
 */
export declare const countHueRange: (colors: Iterable<ReadonlyVec>, minHue: number, maxHue: number, minSat: number) => number;
/**
 * Takes a list of HSV colors, a list of min/max hue ranges and a min saturation
 * (all normalized in [0,1] range). Computes the normalized area of all matching
 * colors.
 *
 * @remarks
 * If given a pixel buffer as input, it MUST be in `FLOAT_HSVA` format. Also see
 * {@link temperature}.
 *
 * See {@link selectHueRange} for details about hue ranges.
 *
 * @param colors
 * @param hueRanges
 * @param minSat
 */
export declare const hueRangeArea: (colors: Iterable<ReadonlyVec>, hueRanges: [number, number][], minSat?: number) => number;
/**
 * Takes a list of hue ranges and computes the area-weighted mean intensity of
 * matching pixels in the given image. Also see {@link temperatureIntensity}.
 *
 * @remarks
 * If given a pixel buffer as input, it MUST be in `FLOAT_HSVA` format.
 *
 * Intensity here means the product of HSV `saturation * brightness`.
 *
 * See {@link selectHueRange} for details about hue ranges.
 *
 * @param colors
 * @param hueRanges
 * @param minSat
 */
export declare const hueRangeAreaIntensity: (colors: Iterable<ReadonlyVec>, hueRanges: [number, number][], minSat?: number) => number;
/**
 * Computes the average intensity of given HSV colors. Intensity here means the
 * product of `saturation * value` (ignoring hues).
 *
 * @remarks
 * If given a pixel buffer as input, it MUST be in `FLOAT_HSVA` format.
 *
 * @param colors
 */
export declare const meanIntensity: (colors: Iterable<ReadonlyVec>) => number;
/**
 * Constructs a min/max range of given normalized `hues` around given `mean` hue
 * (also normalized), considering circular wrap-around. If `min > max` in the
 * result `[min,max]`, then the hue range is crossing zero.
 *
 * @param hues
 * @param mean
 */
export declare const hueRange: (values: import("@thi.ng/api").NumericArray, mean: number) => import("@thi.ng/metrics").Range;
/**
 * Computes an abstract measure of a normalized "color temperature" of the given
 * HSV `colors` (also normalized in [0,1] range). Results closer to 1.0 indicate
 * a prevalence of warmer (red/orange) colors, results closer to -1.0 mean more
 * colder/blue-ish colors present.
 *
 * @remarks
 * Computation is as follows:
 * - Discard colors with lower saturation than given `minSat`
 * - Compute normalized area (percentage) of qualifying saturated colors
 * - Compute the histogram for 12 evenly spread hues
 * - Produce a weighted list of hue angles, based on histogram
 * - Compute circular mean of hue angles
 * - Use {@link hueTemperature} to compute normalized temperature in [-1,1] range
 * - Scale temparature by normlized area
 * - Return object of the various result metrics
 *
 * If given a pixel buffer as input, it MUST be in `FLOAT_HSVA` format.
 *
 * Also see {@link temperatureIntensity}.
 *
 * @param colors
 * @param minSat
 * @param coeffs
 */
export declare const temperature: (colors: Iterable<ReadonlyVec>, minSat?: number, coeffs?: typeof DEFAULT_TEMPERATURE_COEFFS) => TemperatureResult;
/**
 * Default temperature curve hues/coefficients for {@link hueTemperature}.
 *
 * @remarks
 * The four values (all in [0,1] range) are to be giving in this order:
 *
 * - A: start hue of warm falloff
 * - B: end hue of warm falloff
 * - C: start hue of warm rise
 * - D: end hue of warm rise
 *
 * Note: The hot point is fixed at 0 (aka red) and the cold point is fixed at
 * 2/3 (= 0.666... aka blue), meaning C & D MUST be greater.
 */
export declare const DEFAULT_TEMPERATURE_COEFFS: [number, number, number, number];
/**
 * Computes an abstract measure of a normalized "color temperature" ([-1,1]
 * range) for the given `hue` (in [0,1] range). Red/orange/yellow hues produce
 * results close to 1.0, cyan/blue/purple-ish hues produce results closer to
 * -1.0.
 *
 * @remarks
 * Uses one of two smoothstep curves for non-linear interpolation, depending on
 * input hue.
 *
 * @param hue
 * @param coeffs
 */
export declare const hueTemperature: (hue: number, [a, b, c, d]?: [number, number, number, number]) => number;
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