Modify Histogram Based on Embedded Watermark Values

Modify histogram based on embedded watermark values by first applying wavelet transform to convert the image into multiple frequency subbands, then extracting the histogram from one selected subband. This process enables detailed analysis and processing of images, facilitating more precise watermark embedding and extraction operations. The implementation typically involves using wavelet decomposition functions (like wavedec2 in MATLAB) to obtain LL, LH, HL, and HH subbands, followed by histogram calculation using imhist or custom functions for the targeted subband. By comparing histograms across different subbands, we can identify image characteristics and variations at various frequency levels, providing valuable information and additional options for subsequent image processing and analysis tasks. This frequency-domain approach allows developers to implement adaptive watermarking algorithms that consider both spatial and frequency characteristics of the image data.