# applyPolynomial(coefficientSegments:boundaries:destination:) Applies a set of piecewise polynomials to a 2-channel, 32-bit interleaved buffer and writes the result to a 2-channel, 8-bit interleaved buffer. ``` func applyPolynomial(coefficientSegments: [[Float]], boundaries: [Float], destination: vImage.PixelBuffer) ``` ## Parameters `coefficientSegments` An array that contains the polynomial coefficient array. Each polynomial must be of the same order. `boundaries` An array of boundary values, in increasing order, that separates adjacent ranges of pixel values. `boundaries` must contain `coefficientSegments.count + 1` elements. `destination` The destination pixel buffer. ## Discussion The following code shows an example of applying three polynomials to a [`vImage.InterleavedFx2`](/documentation/Accelerate/vImage/InterleavedFx2) buffer: ```swift let src = vImage.PixelBuffer( pixelValues: [0.25, 0.5, 0.75, 1.0], size: vImage.Size(width: 2, height: 1)) let dest = vImage.PixelBuffer( size: src.size) let factor = Float(255) src.applyPolynomial(coefficientSegments: [ [1 * factor, 0, 0], [0, 1 * factor, 0], [0, 0, 1 * factor] ], boundaries: [0, 1/3, 2/3, 1] as [Float], destination: dest) // Prints: // 255 ≅ factor * 0.25⁰ // 127 ≅ factor * 0.5¹ // 143 ≅ factor * 0.75² // 255 ≅ factor * 1.0² print(dest.array) ``` ## See Also --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)