Patent ID: 8768085

Claim:
A Hadamard transform-based image compression method, comprises: selecting a first mode or a second mode of a Hadamard transform; when the first mode is selected, performing the Hadamard transform on 2 k pixel values according to a 2 k ×2 k Hadamard matrix to generate 2 k first transformed values, with k being a positive integer, and quantizing at least one first transformed value of the 2 k first transformed values; and when the second mode is selected, performing the Hadamard transform on the 2 k pixel values according to a product of the 2 k ×2 k Hadamard matrix and a 2 k ×2 k adjustment matrix to generate 2 k second transformed values comprising at least one second transformed value of zero, wherein, the adjustment matrix satisfies a condition that, when the 2 k pixel values are divided into G pixel groups each comprising 2 k /G adjacent pixel values, where G is a positive integer, and the adjustment matrix is multiplied by a 2 k ×1 first matrix composed of the 2 k pixel values to convert the first matrix to a 2 k ×1 second matrix, each pixel value of the first matrix is converted to an average pixel value of a pixel group comprising the pixel value to form the second matrix, and under the second mode, the first mode or the second mode of the Hadamard transform is selected according to a difference between each pixel value of the 2 k pixel values and the average pixel value of the pixel group comprising the pixel value.