Image compression device, image compression method, and image compression program

An image compression method comprising the steps of:

• when compressing second image data, which is obtained by subjecting first image data to an image process affecting frequency characteristics, acquiring a first integrated value by integrating a high-frequency component of the first image data;
• acquiring a second integrated value by correcting the first integrated value in accordance with a change in the frequency characteristics;
• determining, in accordance with the second integrated value, the number of bytes resulting when the second image data is compressed;
• calculating, in accordance with the determined number of bytes, a quantization scale for compressing the second image data to a predefined number of bytes at once;
• and
• compressing the second image data by using the calculated quantization scale.

A non-transitory computer readable medium storing a program causing a computer to execute a process for image compression, the process comprising:

• when compressing second image data, which is obtained by subjecting first image data to an image process affecting frequency characteristics, acquiring a first integrated value by integrating a high-frequency component of the first image data;
• acquiring a second integrated value by correcting the first integrated value in accordance with a change in the frequency characteristics;
• determining, in accordance with the second integrated value, the number of bytes resulting when the second image data is compressed;
• calculating, in accordance with the determined number of bytes, a quantization scale for compressing the second image data to a predefined number of bytes at once;
• and
• compressing the second image data by using the calculated quantization scale.