JPEG in PyTorch

Buy Me a Coffee

*Memos:

• My post explains OxfordIIITPet().

JPEG() can randomly apply JPEG compression to an image as shown below:

*Memos:

• The 1st argument for initialization is quality(Required-Type:int): *Memos:
  • It’s the range of the quality [min, max] so it must be min <= max.
  • It must be 0 <= x <= 100.
  • A tuple/list must be the 1D with 2 elements.
  • A single value means [quality, quality].
• There is the 1st argument(Required-Type:PIL Image or tensor(int(uint8))). *A tensor must be 3D.
• v2 is recommended to use according to V1 or V2? Which one should I use?.

<span>from</span> <span>torchvision.datasets</span> <span>import</span> <span>OxfordIIITPet</span>
<span>from</span> <span>torchvision.transforms.v2</span> <span>import</span> <span>JPEG</span>
<span>jpeg</span> <span>=</span> <span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>100</span><span>)</span>
<span>jpeg</span>
<span># JPEG(quality=[100, 100]) </span>
<span>jpeg</span><span>.</span><span>quality</span>
<span># [100, 100] </span>
<span>origin_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>None</span>
<span>)</span>
<span>q100origin_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span> <span># `q` is quality </span>    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>100</span><span>)</span>
    <span># transform=JPEG(quality=[100, 100]) </span><span>)</span>
<span>q1_100_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>[</span><span>1</span><span>,</span> <span>100</span><span>])</span>
<span>)</span>
<span>q1_50_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>[</span><span>1</span><span>,</span> <span>50</span><span>])</span>
<span>)</span>
<span>q50_100_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>[</span><span>50</span><span>,</span> <span>100</span><span>])</span>
<span>)</span>
<span>q50_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>50</span><span>)</span>
<span>)</span>
<span>q10_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>10</span><span>)</span>
<span>)</span>
<span>q5_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>5</span><span>)</span>
<span>)</span>
<span>q1_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>1</span><span>)</span>
<span>)</span>
<span>import</span> <span>matplotlib.pyplot</span> <span>as</span> <span>plt</span>
<span>def</span> <span>show_images1</span><span>(</span><span>data</span><span>,</span> <span>main_title</span><span>=</span><span>None</span><span>):</span>
    <span>plt</span><span>.</span><span>figure</span><span>(</span><span>figsize</span><span>=</span><span>[</span><span>10</span><span>,</span> <span>5</span><span>])</span>
    <span>plt</span><span>.</span><span>suptitle</span><span>(</span><span>t</span><span>=</span><span>main_title</span><span>,</span> <span>y</span><span>=</span><span>0.8</span><span>,</span> <span>fontsize</span><span>=</span><span>14</span><span>)</span>
    <span>for</span> <span>i</span><span>,</span> <span>(</span><span>im</span><span>,</span> <span>_</span><span>)</span> <span>in</span> <span>zip</span><span>(</span><span>range</span><span>(</span><span>1</span><span>,</span> <span>6</span><span>),</span> <span>data</span><span>):</span>
        <span>plt</span><span>.</span><span>subplot</span><span>(</span><span>1</span><span>,</span> <span>5</span><span>,</span> <span>i</span><span>)</span>
        <span>plt</span><span>.</span><span>imshow</span><span>(</span><span>X</span><span>=</span><span>im</span><span>)</span>
        <span>plt</span><span>.</span><span>xticks</span><span>(</span><span>ticks</span><span>=</span><span>[])</span>
        <span>plt</span><span>.</span><span>yticks</span><span>(</span><span>ticks</span><span>=</span><span>[])</span>
    <span>plt</span><span>.</span><span>tight_layout</span><span>()</span>
    <span>plt</span><span>.</span><span>show</span><span>()</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>origin_data</span><span>"</span><span>)</span>
<span>print</span><span>()</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q100origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q100origin_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q1_100_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_100_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q1_50_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_50_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q50_100_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q50_100_data</span><span>"</span><span>)</span>
<span>print</span><span>()</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q100origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q100origin_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q50_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q50_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q10_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q10_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q5_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q5_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q1_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_data</span><span>"</span><span>)</span>
<span># ↓ ↓ ↓ ↓ ↓ ↓ The code below is identical to the code above. ↓ ↓ ↓ ↓ ↓ ↓ </span><span>def</span> <span>show_images2</span><span>(</span><span>data</span><span>,</span> <span>main_title</span><span>=</span><span>None</span><span>,</span> <span>q</span><span>=</span><span>100</span><span>):</span>
    <span>plt</span><span>.</span><span>figure</span><span>(</span><span>figsize</span><span>=</span><span>[</span><span>10</span><span>,</span> <span>5</span><span>])</span>
    <span>plt</span><span>.</span><span>suptitle</span><span>(</span><span>t</span><span>=</span><span>main_title</span><span>,</span> <span>y</span><span>=</span><span>0.8</span><span>,</span> <span>fontsize</span><span>=</span><span>14</span><span>)</span>
    <span>for</span> <span>i</span><span>,</span> <span>(</span><span>im</span><span>,</span> <span>_</span><span>)</span> <span>in</span> <span>zip</span><span>(</span><span>range</span><span>(</span><span>1</span><span>,</span> <span>6</span><span>),</span> <span>data</span><span>):</span>
        <span>plt</span><span>.</span><span>subplot</span><span>(</span><span>1</span><span>,</span> <span>5</span><span>,</span> <span>i</span><span>)</span>
        <span>jpeg</span> <span>=</span> <span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>q</span><span>)</span>
        <span>plt</span><span>.</span><span>imshow</span><span>(</span><span>X</span><span>=</span><span>jpeg</span><span>(</span><span>im</span><span>))</span>
        <span>plt</span><span>.</span><span>xticks</span><span>(</span><span>ticks</span><span>=</span><span>[])</span>
        <span>plt</span><span>.</span><span>yticks</span><span>(</span><span>ticks</span><span>=</span><span>[])</span>
    <span>plt</span><span>.</span><span>tight_layout</span><span>()</span>
    <span>plt</span><span>.</span><span>show</span><span>()</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>origin_data</span><span>"</span><span>)</span>
<span>print</span><span>()</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q100origin_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>100</span><span>)</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_100_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>[</span><span>1</span><span>,</span> <span>100</span><span>])</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_50_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>[</span><span>1</span><span>,</span> <span>50</span><span>])</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q50_100_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>[</span><span>50</span><span>,</span> <span>100</span><span>])</span>
<span>print</span><span>()</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q100origin_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>100</span><span>)</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q50_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>50</span><span>)</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q10_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>10</span><span>)</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q5_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>5</span><span>)</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>1</span><span>)</span>
<span>from</span> <span>torchvision.datasets</span> <span>import</span> <span>OxfordIIITPet</span>
<span>from</span> <span>torchvision.transforms.v2</span> <span>import</span> <span>JPEG</span>

<span>jpeg</span> <span>=</span> <span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>100</span><span>)</span>

<span>jpeg</span>
<span># JPEG(quality=[100, 100]) </span>
<span>jpeg</span><span>.</span><span>quality</span>
<span># [100, 100] </span>
<span>origin_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>None</span>
<span>)</span>

<span>q100origin_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span> <span># `q` is quality </span>    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>100</span><span>)</span>
    <span># transform=JPEG(quality=[100, 100]) </span><span>)</span>

<span>q1_100_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>[</span><span>1</span><span>,</span> <span>100</span><span>])</span>
<span>)</span>

<span>q1_50_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>[</span><span>1</span><span>,</span> <span>50</span><span>])</span>
<span>)</span>

<span>q50_100_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>[</span><span>50</span><span>,</span> <span>100</span><span>])</span>
<span>)</span>

<span>q50_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>50</span><span>)</span>
<span>)</span>

<span>q10_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>10</span><span>)</span>
<span>)</span>

<span>q5_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>5</span><span>)</span>
<span>)</span>

<span>q1_data</span> <span>=</span> <span>OxfordIIITPet</span><span>(</span>
    <span>root</span><span>=</span><span>"</span><span>data</span><span>"</span><span>,</span>
    <span>transform</span><span>=</span><span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>1</span><span>)</span>
<span>)</span>

<span>import</span> <span>matplotlib.pyplot</span> <span>as</span> <span>plt</span>

<span>def</span> <span>show_images1</span><span>(</span><span>data</span><span>,</span> <span>main_title</span><span>=</span><span>None</span><span>):</span>
    <span>plt</span><span>.</span><span>figure</span><span>(</span><span>figsize</span><span>=</span><span>[</span><span>10</span><span>,</span> <span>5</span><span>])</span>
    <span>plt</span><span>.</span><span>suptitle</span><span>(</span><span>t</span><span>=</span><span>main_title</span><span>,</span> <span>y</span><span>=</span><span>0.8</span><span>,</span> <span>fontsize</span><span>=</span><span>14</span><span>)</span>
    <span>for</span> <span>i</span><span>,</span> <span>(</span><span>im</span><span>,</span> <span>_</span><span>)</span> <span>in</span> <span>zip</span><span>(</span><span>range</span><span>(</span><span>1</span><span>,</span> <span>6</span><span>),</span> <span>data</span><span>):</span>
        <span>plt</span><span>.</span><span>subplot</span><span>(</span><span>1</span><span>,</span> <span>5</span><span>,</span> <span>i</span><span>)</span>
        <span>plt</span><span>.</span><span>imshow</span><span>(</span><span>X</span><span>=</span><span>im</span><span>)</span>
        <span>plt</span><span>.</span><span>xticks</span><span>(</span><span>ticks</span><span>=</span><span>[])</span>
        <span>plt</span><span>.</span><span>yticks</span><span>(</span><span>ticks</span><span>=</span><span>[])</span>
    <span>plt</span><span>.</span><span>tight_layout</span><span>()</span>
    <span>plt</span><span>.</span><span>show</span><span>()</span>

<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>origin_data</span><span>"</span><span>)</span>
<span>print</span><span>()</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q100origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q100origin_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q1_100_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_100_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q1_50_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_50_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q50_100_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q50_100_data</span><span>"</span><span>)</span>
<span>print</span><span>()</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q100origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q100origin_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q50_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q50_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q10_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q10_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q5_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q5_data</span><span>"</span><span>)</span>
<span>show_images1</span><span>(</span><span>data</span><span>=</span><span>q1_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_data</span><span>"</span><span>)</span>

<span># ↓ ↓ ↓ ↓ ↓ ↓ The code below is identical to the code above. ↓ ↓ ↓ ↓ ↓ ↓ </span><span>def</span> <span>show_images2</span><span>(</span><span>data</span><span>,</span> <span>main_title</span><span>=</span><span>None</span><span>,</span> <span>q</span><span>=</span><span>100</span><span>):</span>
    <span>plt</span><span>.</span><span>figure</span><span>(</span><span>figsize</span><span>=</span><span>[</span><span>10</span><span>,</span> <span>5</span><span>])</span>
    <span>plt</span><span>.</span><span>suptitle</span><span>(</span><span>t</span><span>=</span><span>main_title</span><span>,</span> <span>y</span><span>=</span><span>0.8</span><span>,</span> <span>fontsize</span><span>=</span><span>14</span><span>)</span>
    <span>for</span> <span>i</span><span>,</span> <span>(</span><span>im</span><span>,</span> <span>_</span><span>)</span> <span>in</span> <span>zip</span><span>(</span><span>range</span><span>(</span><span>1</span><span>,</span> <span>6</span><span>),</span> <span>data</span><span>):</span>
        <span>plt</span><span>.</span><span>subplot</span><span>(</span><span>1</span><span>,</span> <span>5</span><span>,</span> <span>i</span><span>)</span>
        <span>jpeg</span> <span>=</span> <span>JPEG</span><span>(</span><span>quality</span><span>=</span><span>q</span><span>)</span>
        <span>plt</span><span>.</span><span>imshow</span><span>(</span><span>X</span><span>=</span><span>jpeg</span><span>(</span><span>im</span><span>))</span>
        <span>plt</span><span>.</span><span>xticks</span><span>(</span><span>ticks</span><span>=</span><span>[])</span>
        <span>plt</span><span>.</span><span>yticks</span><span>(</span><span>ticks</span><span>=</span><span>[])</span>
    <span>plt</span><span>.</span><span>tight_layout</span><span>()</span>
    <span>plt</span><span>.</span><span>show</span><span>()</span>

<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>origin_data</span><span>"</span><span>)</span>
<span>print</span><span>()</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q100origin_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>100</span><span>)</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_100_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>[</span><span>1</span><span>,</span> <span>100</span><span>])</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_50_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>[</span><span>1</span><span>,</span> <span>50</span><span>])</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q50_100_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>[</span><span>50</span><span>,</span> <span>100</span><span>])</span>
<span>print</span><span>()</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q100origin_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>100</span><span>)</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q50_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>50</span><span>)</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q10_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>10</span><span>)</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q5_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>5</span><span>)</span>
<span>show_images2</span><span>(</span><span>data</span><span>=</span><span>origin_data</span><span>,</span> <span>main_title</span><span>=</span><span>"</span><span>q1_data</span><span>"</span><span>,</span> <span>q</span><span>=</span><span>1</span><span>)</span>
from torchvision.datasets import OxfordIIITPet
from torchvision.transforms.v2 import JPEG

jpeg = JPEG(quality=100)

jpeg
# JPEG(quality=[100, 100]) 
jpeg.quality
# [100, 100] 
origin_data = OxfordIIITPet(
    root="data",
    transform=None
)

q100origin_data = OxfordIIITPet( # `q` is quality     root="data",
    transform=JPEG(quality=100)
    # transform=JPEG(quality=[100, 100]) )

q1_100_data = OxfordIIITPet(
    root="data",
    transform=JPEG(quality=[1, 100])
)

q1_50_data = OxfordIIITPet(
    root="data",
    transform=JPEG(quality=[1, 50])
)

q50_100_data = OxfordIIITPet(
    root="data",
    transform=JPEG(quality=[50, 100])
)

q50_data = OxfordIIITPet(
    root="data",
    transform=JPEG(quality=50)
)

q10_data = OxfordIIITPet(
    root="data",
    transform=JPEG(quality=10)
)

q5_data = OxfordIIITPet(
    root="data",
    transform=JPEG(quality=5)
)

q1_data = OxfordIIITPet(
    root="data",
    transform=JPEG(quality=1)
)

import matplotlib.pyplot as plt

def show_images1(data, main_title=None):
    plt.figure(figsize=[10, 5])
    plt.suptitle(t=main_title, y=0.8, fontsize=14)
    for i, (im, _) in zip(range(1, 6), data):
        plt.subplot(1, 5, i)
        plt.imshow(X=im)
        plt.xticks(ticks=[])
        plt.yticks(ticks=[])
    plt.tight_layout()
    plt.show()

show_images1(data=origin_data, main_title="origin_data")
print()
show_images1(data=q100origin_data, main_title="q100origin_data")
show_images1(data=q1_100_data, main_title="q1_100_data")
show_images1(data=q1_50_data, main_title="q1_50_data")
show_images1(data=q50_100_data, main_title="q50_100_data")
print()
show_images1(data=q100origin_data, main_title="q100origin_data")
show_images1(data=q50_data, main_title="q50_data")
show_images1(data=q10_data, main_title="q10_data")
show_images1(data=q5_data, main_title="q5_data")
show_images1(data=q1_data, main_title="q1_data")

# ↓ ↓ ↓ ↓ ↓ ↓ The code below is identical to the code above. ↓ ↓ ↓ ↓ ↓ ↓ def show_images2(data, main_title=None, q=100):
    plt.figure(figsize=[10, 5])
    plt.suptitle(t=main_title, y=0.8, fontsize=14)
    for i, (im, _) in zip(range(1, 6), data):
        plt.subplot(1, 5, i)
        jpeg = JPEG(quality=q)
        plt.imshow(X=jpeg(im))
        plt.xticks(ticks=[])
        plt.yticks(ticks=[])
    plt.tight_layout()
    plt.show()

show_images2(data=origin_data, main_title="origin_data")
print()
show_images2(data=origin_data, main_title="q100origin_data", q=100)
show_images2(data=origin_data, main_title="q1_100_data", q=[1, 100])
show_images2(data=origin_data, main_title="q1_50_data", q=[1, 50])
show_images2(data=origin_data, main_title="q50_100_data", q=[50, 100])
print()
show_images2(data=origin_data, main_title="q100origin_data", q=100)
show_images2(data=origin_data, main_title="q50_data", q=50)
show_images2(data=origin_data, main_title="q10_data", q=10)
show_images2(data=origin_data, main_title="q5_data", q=5)
show_images2(data=origin_data, main_title="q1_data", q=1)

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原文链接：JPEG in PyTorch